Wendt Corporation Ex. 1003, P. 1 Wendt Corporation Ex

Wendt Corporation Ex. 1003, p. 1 Wendt Corporation Ex. 1003, p. 2 Wendt Corporation Close Dec., Ex. A HANDBOOK OF .· RECYCLING TECHNIQUES Alfred Arn. Nijkerk and Wijnand L. Dalmijn

The Hague, March 1998 Fourth printing .. Wendt Corporation Close Dec., Ex. A First printing, November 1995 Second printing, February 1996 Third printing, September 1996 Fourth, revised and expanded printing, March 1998

The Royal Library of The Hague Cataloguing-in-Publication Data

Nijkerk, A.A

Handbook of Recycling Techniques I A.A. Nijkerk. - The Hague Nijkerk Consultancy. - Ill. Published at the request of NOVEM/NOH. - With bibliography and index ISBN 90-802909-2-0 NUGI 841 Keyword: recycling

© copyright: Nijkerk Consultancy 1998 All rights reserved. No part of this book may be reproduced and/ or transmitted, by means of print, photocopy, microfilm or otherwise, in total or in part, without the written permission of the copy right holder or the publisher.

Cover photo: Demolition of a 25-year-old Sabena Boeing 747 at Brussels Zaventhem airport. The airplane was scrapped by a hydraulic LaBounty MSD 116 crane-attached shear of 650 tonnes cutting force, with a Verachtert/ Veratech connecting arm and a Verachtert/Veratech, crane-attached shear. The excavators are Hitachi EX 400s. PHOTOGRAPH BY COURTESY OF VAN LEEUWEN RECYCLING, ROTTERDAM, THE NETHERLANDS.

-· Wendt Corporation Close Dec., Ex. A Handbook of Recycling Techniques

Alfred Arn. Nijkerk

and

Wijnand L. Dalmijn

This book was written within the framework of the Dutch National Reuse of Waste Research Programme (NOH). Project number: NOH/353293/0710

Management and co-ordination of the NOH programme rest with:

NOVEM Netherlands Agency for Energy and the Environment

RIVM National Institute of Public Health and Environmental Protection

The authors can give no guarantee of the accuracy and/ or comprehensive nature of information, designs, constructions, products or production methods arising or described in this book, nor of their suitability for any given specific application.

Published by Nijkerk Consultancy, Ruychrocklaan 202, NL-2597 EC The Hague, The Netherlands. Tel: +31 70 324 33 34 - Facsimile +31 70 324 29 92

Distributed in North America by 'Scrap', a bi-monthly magazine published by ISRI, the Institute of Scrap Recycling Industries, 1325 G-Street NW, Washington DC 20005-3104. Tel.: +(202) 662 8540, Facsimile: +(202) 626 0940.

-· Wendt Corporation Close Dec., Ex. A 'Design for Recycling' in practice. The Dutch Ministry of the Environment, equivalent of the US EPA, moved to new premises in The Hague in 1990. The building is fully recyclable and contains among other things 2000 tonnes of recycled concrete, derived from six demolished viaducts around Rotterdam. The internal walls are fire-resistant and made from paper stock mixed with gypsum and fly-ash from a power station. A total of 3100 civil servants work in this building.

Wendt Corporation Close Dec., Ex. A I Table of contents

Foreword 8

Methodology 10

Chapter I Cycle of materials 11 1 Primary and secondary materials 11 2 Complexity threatens the cycle 11 3 Design for recycling can restore the cycle 13

Chapter II Concepts and terminology 14 1 No uniformity - primary or secondary 14 2 Recovery, recycling, reclamation or re-use 14

Chapter III Recycling through the ages 18 1 Eleven thousand years of melting 18 2 Metals for warfare and knives 18 3 Recycling and the seven wonders of the world 21 4 Was the Roman Empire ruined by (old) lead? 21 5 The nineteenth century 23 6 Ships, a new source for recovery 25

Chapter IV Early techniques 27 1 De-riveting and beating, nineteenth century dismantling 27 2 Dismantling with fire and frost; hacking 28 3 Remelting 29

Chapter V Current processing techniques 31 1 Introduction 31 2 Drop-ball breaking or 'tupping' 32 3 Cutting torches 34 A Ring conduit, batteries or a tank 36 B Limitations 37 C Gas cutting - the technique 38 D Pros and cons of cutting torches 38 E Powder, plasma and laser-beam torches 40 1 Powder torches 40 2 Plasma torches 40 3 Laser cutting of metals, plastics etc. 41 4 Water-jet cutting 42 5 Abrasive-disc cutting 43 6 Shears 44 A Alligator shears 45 1 Hydraulically-driven alligator shears 47 B Special shears 47 C Crane-attached shears 48 1 Variations in crane-attached shears 49 D Hydraulic guillotine shears 53 1 Cut-throat history 53 2 Concrete and steel foundations or trailer mounted 56 3 Push, hold-down, side-compress and cut 59 4 Variations in hydraulic guillotine shears 63 7 Balers 65 A From horizontal to vertical and back again 65 B Metal balers and loggers 66

Wendt Corporation Close Dec., Ex. A 1 Metal baling, the system 67 C Balers for paper stock, textiles, plastics, cans and drums 69 1 Essential differences from metal presses 69 2 Downstroke balers 71 3 Horizontal paper balers 73 4 Single-ram and two-ram balers 75 5 The closed-end baler 76 6 Accessories 76 7 Safety 77 8 Manufacturers 77 D Briquetters 77 8 Car flatteners 79 9 Cable strippers 80 10 Rotary shears I shredders 82 11 Shredders 85 A Types of shredder 85 B History and development 87 1 Ore and turnings crushers first' 87 2 1958, the year of the first automobile shredders 88 3 Complete automobile and non-ferrous yield as a bonus 92 4 Shredders, mainly from the US, Germany and Japan 93 C Method 95 D The automobile shredder 95 1 Feed and types; costs and personnel 98 2 Automobile shredder-process description 99 a The input or feed 99 b Shredding 101 c The dust collection system 105 d The heavy metallic fraction 106 e The non-magnetic fraction and shredder waste/fluff 107 E Other types. Zerdirators, Kondirators and Mills; HD and SHD shredders 108 1 The Zerdira tor 108 2 The Kondirator 110 3 The Henschel Mill 110 F 'Wet' shredders 111 1 Advantages 112 2 Disadvantages 113 G Accessories and peripherals 114 H Pre-shredders/rippers 117 1 Return after 25 years 117 2 Advantages 117 3 Disadvantages 120 4 Considerations 120 5 Three kinds of ripper 121 I Cryogenic shredders 122 J Cable shredders and wire choppers 123 1 Various types 123 2 Burning, stripping or shredding 124 3 Shredding is fast, but not without problems 125 4 Shredding of plastic-sheathed cable 126 5 Shredding of armoured cable, 'warm' or 'cold' 127 K Aluminium shredders 127 L Rubble crushers 129 1 Not real shredders 129 2 Crushing in two stages 129 3 Fixed or mobile installations 131 4 High throughput 132

Wendt Corporation Close Dec., Ex. A 5 The infeed 132 6 Pre-crushing 133 7 Types of rubble crusher 134 8 Cleaning the material 135 9 Microwaves assist rubble crushing 135 M Paper shredding 137 1 Safety 140 N Tyre shredding 140 0 Shredders for 'green' waste 142

Chapter VI Ancillary equipment 144 1 Introduction 144 2 Aids to collection 145 A Collection from citizens 146 B Collection at offices, catering establishments and institutions 150 C Collection - and internal transport - at companies 151 3 Aids to storage at companies 154 4 Ancillaries for transport of secondary raw materials 156 A Special containers 156 B Loading and unloading 157 1 Magnets 158 2 Grapples for loading and unloading 161 5 Ancillaries for motor vehicle dismantling 163 6 Weighing aids 165

Chapter VII Identification, sorting and separation 168 1 Increasing complexity demands additional action 168 2 Sorting and separation - the essentials 170 3 Identification and sorting 171 4 Visual identification; colour, weight, shape and application still reveal too little 171 5 Mechanical identification - radiation detection 175 6 Mechanical processing by sorting/separation 178 A Dismantling 179 B Processing by dry separation 181 1 Gravity separation 181 a Industrial screening 181 b Centrifuges and cyclones 182 c Air classification 182 d Friction separators and shaking tables 185 2 Dry separation with electro magnetics 187 a Magnetic separation 187 b Eddy current separation 188 3 Electrostatic separation 194 4 Particle for particle sorting 196 a Metal detection 196 b Sensing systems based on light 198 5 Image processing 202 C Processing by wet separation 204 1 Rising current and hydro-cyclone methods 204 2 Sink-float method 205 3 Jigging 207 4 Flotation methods 207 D Melt separation 208

Bibliography 211

Index 212

Wendt Corporation Close Dec., Ex. A Foreword

" ... And they shall beat their swords into ploughshares, and their spears into pruning hooks ... " (Isaiah 2:4)

Recycling techniques, even in their most simple forms, are at least 50 centuries old, but scientific interest in them remained limited. Literature on the subject is exceedingly scarce, even today.

In the light of the overwhelming interest which recycling has enjoyed in recent years, this is very surprising. It is possibly a consequence of the fact that hardly any where are there organised courses on recycling and recovery techniques, let alone at academic levels.

Over the last decade recovery techniques have taken off - particularly identification, sorting, processing and separation - un doubtedly stimulated by political and economic factors.

Political stimulus came mainly from gov ernment authorities, which saw that only through prevention and re-use would it be possible to counteract the growing moun tain of waste. 'From swords to ploughshares.' On the economic/technical side the recy This sculptural interpretation of the Biblical text cling sector took the lead. It was compelled stands in front of the United Nations building in New to develop new techniques to be able to York. A gift from the Russian people, it is the work of recycle the fast-growing stream of ever Yevgenii Vuketich. more complex consumer goods, which furthermore had ever shorter economic and technical life-spans. Here the almost total In this book, the authors aim to give lack of 'Design for recycling' in the past took a readable account of the historical and its toll. existing recovery and recycling techniques.

Knowledge of existing recycling techniques Perhaps there will be surprise at the multi is important to recyclers themselves, but is tude of already available and often fascinat also becoming of vital importance to every ing techniques which can be used for the manufacturer of consumer goods, whether reclamation of raw materials. large or small. Yet the emphasis here is still on the process ing of metals. There, thanks to their great With Germany in the lead, government variety, differences in weight and bulk and authorities are to an ever-increasing extent their relatively high strength, a wider range forcing industrial companies to take back of techniques has grown than those used their products when they are discarded - for e.g. paper, textiles and plastics, where whether packaging, electronics, or old cars. sorting by hand is generally still essential. It is, then, of great importance to these industries to know which reclamation Recycling installations were visited by the techniques can be applied. authors in almost all West European coun-

Wendt Corporation Close Dec., Ex. A 1

Recycling of bronze, in 1778. A cracked bronze cannon is remelted at the Royal Brass Foundry in Woolwich, UK. PICTURE BY COURTESY OF DR J. T. SEMEIJNS DE VRIES VAN DOESBURG.

tries, the United States, Latin America, the The authors - see back cover -, owe the P.R. of China and Japan. above persons and bodies a large debt of gratitude for their support. The same Advice and corrections came, among others, thanks go to the many companies now from M. Adolph Dpl.Ing. of Svedala Linde involved in the design and realisation of mann Dlisseldorf (D), ir. A. Ansems of TNO new machines and techniques and which National Research Institute (NL), Ian Cooper supplied the author with much in the way (UK), ing. H. van Doorn of MBH Helmond of valuable data, photographs, flowsheets (NL), Jim Fowler of ISRI's 'Scrap' (USA), and the like. professor dr. ir. Ch.HF. Hendriks of Delft Technical University (NL), ing. D.R.J. Lafebre • of Hoek-Loos/Holox (NL/USA), RF. Mur Alfred A. Nijkerk, ray of Svedala Hammermills, Cedar Rapids Wijnand L. Dalmijn (USA), Scott Newell of Newell Industries March 1998 Inc., San Antonio (USA), Sam Proler, Miami (USA), Jim Schwartz of Texas Shredder Inc., This fourth printing is a considerably revised San Antonio (USA) and M. de Weerd of and expanded edition, now in co-authorship RIVM (NL), and were most welcome. with Professor ir. W.L. Dalmijn.

This book has come about partly at the request of NOVEM/NOH, The Netherlands Agency for Energy and the Environment and thanks to the financial support of this Agency.

-· Wendt Corporation Close Dec., Ex. A Methodology

Recycling, the cycle of new I old/ new, is mention of hand tools such as hammer, a complex process often comprising a num chisel and tongs, although these are used by ber of successive actions. These are aimed at almost every metals recycler. Torch-cutting bringing used or discarded consumer pro is described in detail, however, since this is ducts, industrial by-products and residues, an important, specific and indispensable and capital goods back into the cycle. technique for the processing of scrap, especially for larger objects such as ships. The following distinction is made between these actions: Recycling and recovery are on an upward A. - Processing: Chapter V trend; new and varied techniques are B. - Collection and transport: Chapter VI continually being developed. Therefore this C. - Identification, sorting and separation: book can never be quite complete. How Chapter VII ever, this updated (1998) version will D. - Remelting and pulping hopefully give a systematic insight into what is currently available and possible in The last item is left outside the scope of this the field of what the author regards as the book: remelting - in the widest sense, and important techniques. also the pulping of paper stock and card board - covers such an extensive field that in Please note that when tonne(s) is mentioned in our view it would require a separate book. this book, it will refer to metric tonne(s).

The chapters in this Handbook of Recycling • Techniques fall into three divisions. After an introduction (Chapter II) and a brief review of the history of recycling, the earlier and current processing techniques are discussed (in Chapters IV and V respectively). Then in Chapter VI the ancillaries of recycling and finally, in Chapter VII, the techniques for identification, sorting and separation.

The reader will notice how diverse are the technical aids which the recoverer and recycler have available to them. In recent decades, a whole industry has arisen which specializes in the fast-growing recycling market. The products of this in dustry, such as shears, balers and shredders, and equipment for loading, analysis and sorting, are described here as far as possible.

As already mentioned in the Foreword, most attention is paid to the techniques concerned with recycling of metals. It is in this sector that most mechanical processing takes place, and therefore here considerably more technical developments are to be seen than, for example, in the processing of paper stock and textiles.

The authors have deliberately omitted 10 .. Wendt Corporation Close Dec., Ex. A r Not only scrap is briquetted, but also materials such as wood chips, tobacco, reject bank notes, and other security-sensi tive products. In the last two cases, the main reason is to render them unusable. In the latter instances, briquetting is carried out continuously in contrast to the turn ings. The extrusions are easily cut to the desired length, and are almost always used as fuel. Various timber companies and security printers use them to fire their heating boilers.

As a test, hundreds of thousands of British banknotes were delivered - in an armoured vehicle and under heavy police escort - to Fig. V-8-3 Flattening with a beam fabrication driven one of the producers of these machines in down hydraulically. The Netherlands, to be permanently 'de PHOTO BY COURTESY OF AL-JON, OTTUMWA, USA. faced' by shredding and subsequent bri quetting. But in the US the idea of crushing hydrauli cally soon arose. In the first machines, Domestic and/ or industrial waste is also a steel beam was pulled down on the car briquetted, usually into pellets which make by a hydraulic cylinder at either end a very good fuel and are sold as such. (Fig. V-8-3).

8 Car flatteners Then Al-Jon, of Ottumwa, Iowa, produced an ingenious but simple system in which Flattening or crushing old automobiles the old automobile was pushed in stages makes them suitable for economic transport under a stepped lid, flattened progressively to the shredder; this is a preparation for under the axle of the lid, and ejected. The shredding. heavy lid, in the shape of inverted steps, was pulled down by two hydraulic cylin Flattening was originally achieved by ders. (Fig. V-8-2) dropping a heavy steel plate or block of concrete on the vehicle's roof from a crane. The step shape had the advantage that the automobile first passed under the highest 'step', with the least pressure, which only had to crush the roof. The deeper the car Fig. V-8-2 The typical stepped lid of the Al-Jon was pushed under the steps the greater flattener, which progressively renders the scrap car into were the forces exerted upon it. a pancake. PHOTO BY COURTESY OF AL-JON, OTTUMWA, USA. Fig. V-8-4 Mobile flattening: the flattener is attached to a loader. PHOTO BY COURTESY OF HAWKFAWK, U.K.

.. 79 Wendt Corporation Close Dec., Ex. A l'

Fig. V-8-5 Sea-borne car flattening. This barge with its two (MBH) car flatteners, serves the towns along the more than 2000 miles long Norwegian coast. On the left, is a stack of white goods waiting to be processed and a pile of flattened car wrecks which will be transported to shredders around Oslo. PHOTO TAKEN AT SEVERIN EILERTSEN, NORWAY.

It was finally ejected as a 'pancake' some Electric cables are often very complex 20-30 cm thick. (Fig. V-9-3): a copper or aluminium core - Soon many variations on this principle sometimes with steel strengthening wires emerged, a convincing success being the inside - surrounded by various layers, Mosley /MBH (Bronneberg) system which including lead, impregnated or oiled paper, had a hydraulically pulled-down 'lid' (see rope, textiles or plastics. Furthermore these Figs. V-8-1 and V-8-5). cables are often sheathed in galvanized and/ or tarred steel. Also other, baler-like, crushers came on the Various techniques are available to free the market, some with one or two 'wings' - just valuable copper, lead, or aluminium from like a scrap shear's side wings - which electric cable. simply flattened the old automobile. Other They can be divided into: designs resembled the fingers of two hands - stripping clasping together to flatten the vehicle. - shredding/chopping (described in Section 11-J) 9 Cable strippers - burning

The process described here must not be Nowadays, cables sheathed only in plastic confused with the 'stripping' - dismant are mostly shredded. The usually thicker ling - of old automobiles. By 'stripping' we paper-insulated 'underground' or 'sub mean here the splitting-open or 'peeling' of marine transatlantic' cables however are old electric cables, a technique that has usually stripped after being cut into con been around for many decades. venient lengths (Figs. V-9-1 and 2).

-- Wendt Corporation Close Dec., Ex. A ·---,

permissible in the open, or even in a fur nace, in developed, environmentally conscious countries, unless measures have been taken to counteract emissions of smoke or chlorine and dioxins. See also Section 11-J-2. This requires expensive modifications.

The water curtains often used in the past to absorb the greasy smoke no longer comply with stricter environmental requirements. After-burners can sometimes be used to achieve an acceptable result, but this re quires fairly substantial investment. There are also problems when melting armoured cables with aluminium cores. The melting point of aluminium lies only some 325°C above that of lead, so there is a danger that the aluminium will turn to slag if the temperature is not accurately controlled. This is difficult because of the presence of the often unknown amounts of com bustible materials, which are commonly used in underground cables.

Of course cutting the cable to an appro priate length for burning is an additional laborious process. Cable cutters have already been dealt with in Section V-6-B, Special Shears. Fig. V-9-1 Cable stripper for manual feeding. Machines to strip cables were developed

Burning of heavier, underground, cable was carried out in stages. First cables were Fig. V-9-2 Operation of a mobile cable splitter/ cut to lengths of about 1 metre, then laid on stripper. SKETCH BY COURTESY OF EUROPARTS a slightly tilted curved steel plate, and set RECYCLINGTECHNIK, SCHENKLENGSFELD, GERMANY. afire. Once the fire was lit, the cable easily gene rated enough heat to propagate the flame, thanks to the abundant presence of mastic, impregnated (bituminous) paper, oils, grease or jute. On reaching a temperature of 327°C, the melting point of lead, the liquid metal flowed from the cable. Once the lead had flowed away, the copper wires and the remaining steel sheath could be withdrawn from the ashes with relative ease. The lead was usually captured in casts to make ingots, which could be sold for further refining or as ballast blocks. There is a still a fairly large market for the latter use, particularly among elevator (lift) manufacturers and for the keels of yachts.

Understandably, burning is no longer .. 81 Wendt Corporation Close Dec., Ex. A For old cables which consist only of a copper or aluminium core in a plastic Aluminium sheath, shredding or granulating is a con siderably faster method. See Section V-11-L PVC cable shredders. Copper Shredding is often unsuccessful where so-called paper insulated and underground cables containing protective grease are Filler concerned, for which manual stripping is still used.

PVC Aluminium cables used for high-voltage transmission often have one or more steel carrier wires in their core. Removing these by conventional methods is difficult be cause the aluminium wires are wrapped around the core in spirals. Copper/plastic Stripping offers no real solution because the spiral wires would constantly need to be unwound.

PVC There is a very simple method of removing the steel core quickly, first by feeding it through a small hole drilled or torched in Fig. V-9-3 The recycler's concern: an underground a vertical steel plate. The steel wire is now cable is a conglomerate of raw materials. attached to a winch, so that the aluminium is pulled against the steel plate.

even before the Second World War and are The aluminium wires will 'bunch up' usually described simply as cable strippers, against the plate, as they are obviously Fig. V-9-2. Most of these machines are on unable to pass through the small hole. wheels. In this way, steel wire ends up on one side They slice open the cable which has been of the steel plate, and a thick bunch of cut to a manageable length, after which the aluminium on the other. copper and aluminium wires can be pulled out by hand and the open lead sheath In some scrapyards an old automobile is subsequently removed. used to power this process, the engine driving one of the rear wheels as a winch. A cable stripper or splitter usually consists Recycling with a recycling item. of two feed rollers which pass the cable between finely-ground rotating cutting Something similar has been seen previously disks, or under a fixed hard steel plough. in the use of a dismantled ship's winch to The distance between upper and lower pull a vessel up the breaking slipway. disks, or beneath the plough is adjustable Cryogenic shredding of cables is described to the cable thickness. in Sections 11-1 and J.

However, this stripping method is slow, for 10 Rotary shears/shredders only a few metres of cable can be processed per minute. Besides, the cables must have These are not really shears in the sense of a minimum thickness of about 1 cm. alligator ('kitchen scissor') or guillotine So these strippers are for instance too crude shears, the 'cutting' being more a matter of to cope with domestic appliance cables. ripping and shredding. Furthermore, the hard steel sheaths of many underground cables present con The name rotary or rotor shear can therefore siderable problems in stripping. cause confusion, and some manufacturers

Wendt Corporation Close Dec., Ex. A Fig. V-10-1 A slow speed, high torque rotary shear/shredder. This machine works with two horizontal counter rotating shafts. PHOTO BY COURTESY OF KUSTERS/MOCO, VENLO, THE NETHERLANDS.

prefer to use the terms granulator, grinder, Processing in big automobile shredders has shear-type shredder, or low-speed high torque the disadvantage that the cans are 'rolled shear or shredder, or simply rotary shredder. up', after which removal of paint is more The rotary shear consists of two or four difficult. Another objection is that cans horizontal counter-rotating shafts, to which which contained thinners or other highly round disks with hard steel teeth are attached. Electrical or hydraulic power may be used. Some, however, have only Fig. V-10-2 Rotary shear/shredder chewing-up one shaft and the material is shredded a wooden pallet. against the wall. PHOTO BY COURTESY OF ABT, HENGELO, THE NETHERLANDS.

Rotary shears have a wide repertoire - from smaller objects such as cans, to larger items such as motor tyres, which are hard to cut because of their elasticity. They are also commonly used for the reduction of wood - boxes and pallets, for example - and plastic objects such as old garden chairs, and even to rip apart agri cultural sheet etc. Of course cans could also be pressed - they are often too small for normal cutting - but in that case it is generally no longer possi ble to remove any residual contents such as paints that may be hazardous. 83

Wendt Corporation Close Dec., Ex. A make normal shredders look like entire factories - such as the large dedusting cyclones, trammels, magnets, many con veyor belts etc. (Fig. V-11-1)

A rotary shear is usually driven by one or two relatively small - 10-100 hp - electric motors. It processes some 5-50 tonnes per day, depending of course on the type of material. Some very large domestic waste rotary shears come outside this range and also the pre-shredders or rippers described in 11-H. An automobile shredder of say 2000 hp will process considerably more scrap in an hour than an average rotary shear will manage in a day. Rotary shears are often found in combina tion with other recycling equipment. Fig. V-10-3a This rotary shear/shredder works with British banknotes, referred to earlier, were briquet four horizontal counter-rotating shafts. PHOTO BY processed in a rotary shear before COURTESY OF UNTHA, AUSTRIA AND NIDO, THE NETHERLANDS. ting to render them completely unusable, Section 7-D. flammable substances, may cause an explo sion in the shredder. Wooden pallets are also first ripped up by This is why cutting/ripping with low-speed a rotary shredder before being made into high-torque rotary shears is preferable. chipboard or another product. (Figs. V-7-7 Furthermore, it is simple to introduce an and V-10-2) inert gas into the rotary shear to minimize the risk of explosion. · It is interesting to note that the main pro duct of some wood recyclers is often new Old paint cans for example, are cut up or pallets, this time pressed from wood chips. ripped apart in the rotary shear, after This may be seen as the cycle of materials which further cleaning - possibly cryogen via a detour, or if preferred, the 're-use for ic, see V-11-I - or de-tinning, for example, is the same purpose' described in Chapter II; possible. perhaps one can even speak of the 'second ary recycling' also described there. Rotary shears, or rotor shredders, are particularly useful for processing alumini Fig. V-10-3b This rotary shearing system has two um foil. In a normal shredder the soft foil is main rotors (H) which can give way if unshearable raw likely to become wrapped around the fast material is fed into the machine; the rotation is then turning rotor, as happens with aluminium automatically reversed. or steel wire. The two support rotors (N) will assist when bulky Waste processing plants now also use very material is to be processed. large rotary shears to reduce bulky items of SKETCH BY COURTESY OF UNTHA AND NIDO. domestic refuse like mattresses and furni ture.

Main differences between a shredder and a rotary shear are: In a rotary shear the blades - discs with teeth - are fixed to the shafts. In a shredder the blades, known as 'hammers', swing freely from a rotor which will often be many times heavier than an entire rotary shear. Of course, rotary shears do not have all the accompanying paraphernalia which

Wendt Corporation Close Dec., Ex. A 11 Shredders material and drive it through sizing grates, further reducing this scrap to the desired 11-A TYPES OF SHREDDER size and density. A medium-size shredder uses between 10 Although the word shredding primarily to 12 or up to 36 reversible hammers, each brings to mind the big automobile shredders, weighing some 125 kg or more, to pound or fragmentizers, which first came on the and chop automobile hulks and domestic market around 1958, there are many types appliances to fist-size pieces. in use. Shredders are often classified in four rather special categories: They can range from the small, often por table, paper shredders in offices, with 1- Mini-shredders generally have two rotors motors of less than lhp, of which tens of turning in opposite directions in the hori thousands have now been sold, to the zontal plane, with fixed cutting/ripping mighty 'super heavy duty' (SHD) or 'mega', discs, i.e. small rotary shears/shredders. shredders of more than 7000hp, which can They range in size from less than lhp to easily cost well over $5 million each. around 350hp. The production (input Between these extremes there is a wide weight) of these shredders varies from spectrum of shredders, including the rotary several hundred kilos or a few tonnes shears or shredders of the previous chapter. a day, to some hondreds or thousands of tonnes per year. An automobile shredder is based on the principle of a fast-rotating rotor equipped N.B.: Similar to this category, but many with hammers which cut - shred - the raw times larger, are the 'pre-shredders' - also

Fig. V-11-1 An automobile shredder is a complete factory. Note the huge dust collection system - dedusting unit - on the left. The rotor housing is in the middle of the photograph; on the right, the control cabin and inclined feed conveyor. PHOTO BY COURTESY OF SVEDALA LINDEMANN, GERMANY.

Wendt Corporation Close Dec., Ex. A r

Fig. V-11-la Shredder schematic. SKETCH BY COURTESY OF NEWELL INDUSTRIES INC., SAN ANTONIO, USA.

known as 'rippers' - as described separately Europe, the input 1 capacity ranging from in section 11-H. Their capacity, however, is 40,000 tonnes to 150,000 tonnes per year. in the range of the next category. In North America, however, autoi:nobile shredders are classified by the diameter of 2- Medium-size shredders operate with the hammer circle inside the shredder - i.e. a rotor turning in the horizontal or vertical rotor with hammers extended - and by the (mills, turnings crushers) plane. nominal shredder width. For instance a These shredders usually have free-swing '80104' shredder indicates a rotor diameter ing hammers attached to the main rotor by of 80 inches and an effective inside width a shaft. of 104 inches; the actual feed opening may . The mills, or vertical shaft crushers/ grind be less. ers, often have impact rings instead of The 'large' American shredder is, in gene hammers, see 11-E-3. Shredding power ral, somewhat bigger than its European ranges from around 350 to lOOOhp. counterpart. Production (input weight) ranges from 10,000 to 40,000 tonnes per year. 4. Very large shredders are generally des cribed as heavy duty (HD), super heavy duty 3. Large shredders differ from the medium (SHD) or mega shredders. These are gene sized mainly in their power in Europe, or rally from 4000hp to 7000hp - if that is the rotor size in North America. limit. In North America they are classified Large shredders form the majority of in the 98 104 to 122-108 range (122in ham automobile shredders, of which there are now mer circle, 108in effective width of the (1998) over 800 in the world, including shredder opening). more than 220 in North America, 100 in Input capacity can be over 600,000 tonnes Japan (of a total of 185) and over 40 each in per year. See also 11-E. A large shredder UK and Germany. can have a lower hp and be very succesful. In Europe shredders are in general con sidered to be large when their shredding 1 Input refers to the gross weight of material fed into power - of the main driving motor - is the shredder. Output generally refers to the net between 1000 and 3000hp. Currently the production of metals - excluding non-metallics such 1250hp shredder is very popular in West as glass, plastics, rubber etc.

-- Wendt Corporation Close Dec., Ex. A Zulilhrplatttnband II MagneHrommel Stoei·be/lfef/dingC011veycr If Maf)flelicdrvm 1 ConvoyE1Ur1fahmen1a1,on~ec:aines Tambou,magnit1,que Zulilhrschurt& 12s1ahlsonierband Fdedingchu/e 12 S1tJelsarti11gll81t 2 Goulot!ed·a~men1a1,on Convoyeurdelnagepourl"ac,er ZEROIRATOR"' 13S!ahlabwurRland .-:;RD/f/ATOR 13 S1-1eldi$c:harge1Je// 3 ZEAOIAATOA·~ Convoyeurorien1abled·bacua~on Hauptantriebsmotc.r 14S!aubbaM Maindlivllmotor 14 Dust/Jeff 4 \4011;1urpn.ic;ipaJd"en1rainemen! Convcyeu,.llste11les Vib1ationsdampfung ISSlaubvorladeband Vibralionabs0lb6r 15 Dusldischarga/Jell 5 Amonisseursdevrtlta!ions Convoyeu1dechargemenlsdess!!!riles Hammerausbau•Vorrich1ung 16 NE·Metalf.Sanie,band Hammer dismantling device l6Non•f&rrousme1atsanmgllelt 6 Oisposit1lpou,ledtmon1agedesmanea111 Bandede1ria9epourlesnon-lerreux Sleuerkabine 17Entstaubungsanlage Ccmrolc:a/Jin 17 Ouslox/ra/ionoquipmenl 7 Cabinedecommande lnstallalicndedi!pouss1erage Vibrationsl6rde1er 18 Metmal!en·Bandwaage Villratingconveyar IBMu//l•ro/lBrbBllw&igher 8 Convoyeu1vibl"an1 Basculemu11,.roul&aux Gurtl01dere1 19 Sieblrammel B111/convsyor 19 Scresningdn;m 9 Coiwoyeur~tapis Tambou1c1ible Silparlen,om!Tltll 20 Oberband·Magnelscheider Separatingd11Jm 20 Overbiind magnetic separa1ar 10 Tambourdenenoyage Sep,arateu1magndr,que"overband"

Fig. V-11-lb Scheme of a Svedala Lindemann Zerdirator - with upper and lower grate - plant. See also Fig. V-11-3 sketch B

For example, in Montreal, Canada a 98 104 Rapids whose product is the Svedala Ham processes 70-90 tph with a 2000hp motor. mermills shredder. In Europe three German manufacturers are Any of the shredders in categories 2, 3 and market leaders, namely: Svedala-Lindemann 4 can be constructed as a TD or a TBD, or Maschinen Fabrik GmbH of Dtisseldorf, a SHD, with the following meanings: TD = Henschel GmbH of Kassel and Svedala-ORT, Top Discharge, TBD = Top and Bottom Dis Oberlander GmbH of Dortmund. charge, or SHD meaning Super Heavy Duty. In Japan Kawasaki Heavy Industries Inc, Fuji According to US shredder manufacturers Car and Morita are the main manufacturers. a Super Heavy Duty machine is not desig nated by the horsepower, but its construc 11-B HISTORY AND DEVELOPMENT tion. In general, it means that the shredder housing is constructed from 4in (100 mm) 11-B-1 ORE AND TURNINGS CRUSHERS FIRST plate and that the rotor bearings are very large. It also means that the rotor features L.A. By-Products in Los Angeles was the a design with larger pin shafts and special first to shred steel scrap and did so in the ly-designed hammers. It is only in this way 1920s. It prepared ferrous scrap for use as that very heavy scrap can be processed leaching material for copper production. without damage to the equipment. The terms SHD and Megashredder were Turnings crushers were already popular in first used by Newell to describe the new the 1930s having been developed from ore generation of shredding equipment. and stone crushers. Well-known at the time were the Swedish Arboga crushers, which Main builders of automobile shredders are looked much like large coffee grinders, in USA: Newell Industries Inc, San Antonio, some 2-3 metres in height and 1-2 metres in Texas Shredder Inc, San Antonio and Sveda diameter. These Arboga crushers are still la-Universal Engineering Inc. of Cedar widely used in the recycling business. 87

Wendt Corporation Close Dec., Ex. A Unlike automobile shredders, turnings concept of 'shredding' was hardly known r crushers operate on a vertical axis. in the recycling sector before that time. When these devices have to break normal carbon steel turnings, alloy steel swinging 11-B-2 1958, THE YEAR OF THE FIRST rings are generally used. However, break AUTOMOBILE SHREDDERS. ing alloy steel turnings often requires the greater impact-force of hammers. It was not a coincidence, but a necessity Because of the great elasticity of steel that the automobile shredder appeared at turnings, baling is not an appropriate the end of the 1950s. method. Steel turnings are, however, often briquetted after being crushed. The first batch of post-war automobiles was ready to be scrapped and, further Turnings crushers and shredders are gene more, the steel industry wanted a higher rally used only by specialized scrap compa quality of scrap than that provided by the nies, with the emphasis on the crushing of 'automobile bundles' with which they had alloyed - stainless steel and chromium been supplied in hundreds of thousands of steel - turnings. The idea of scaling-up tonnes. These consisted of complete auto these shredders or crushers to automobile mobiles compressed or logged into a single shredders seemed impossible until the end large, heavy bundle. These bundles, of of the 1950s. Partly because of this, the U.S.-made automobiles in particular, not uncommonly weighed more than a tonne.

Fig. V-11-2 Development of shredding techniques. In The increasing proportions of glass and 1958, when the first automobile shredders were built, synthetic materials used in automobiles at the car wreck was just dropped on to the rotor, creating that time, and particularly the large a heavy strain on it and on the motor (sketch 1 and 2). amount of chromium being employed, The early shredders all discharged through bottom made these bundles less and less attractive grates only. The second generation of shredders (3) in to the steel industry. the 1970s had side feeding plus one or more feeding! Furthermore quite a lot of tin was used for flattening roll(s). Hammermills, however, introduced a filling dents in car bodies, and tin is compression feeder (4) of the crawler-tractor tread type. a particularly harmful element in steel Newell designed a top (and top/bottom) discharge making, especially if the mill is producing system which was licensed to Lindemann and certain thin sheet. other shredder manufacturers. Added to that was the start of the replace ment of the slow open-hearth (Siemens Martin) furnaces, based on a 40-60 percent scrap charge and a melting time of four to six hours per batch, by the much faster LD (Linz-Donawitz) process, also known as the BOF - Basic Oxygen Furnace - or Oxystee/ process.

With the BOF process the melting of a batch takes only half-an-hour to an hour. There was now great pressure on the time required to melt and remove the impurities from the steel bath; solid or compressed scrap often has too little time to melt to the core in an oxysteel furnace. Furthermore - and partly because of this - the BOF furnac es use far less scrap than open-hearth furnaces, varying from around 10 to 35 percent input of scrap metal, the balance being liquid iron from the blast furnaces which are almost always present at this type of integrated steelworks.

-· Wendt Corporation Close Dec., Ex. A 1. Vertical Reject Door - Hydraulically controlled expul sion of unshreddables to help prevent damage to the shredder.

2. Tie Bolts - Exclusive reinforcing tie bolts give secure support to the housing to prevent expansion of walls. 3. Outer Top Breaker Bar - A one-piece dropped wall casting directs the material more efficiently. 4. Rotor - Massive spider type, precision machined and balanced rotor features spherical self-aligning roller bearing to absorb shock, radial en thrust loads. Replaceable capped rotor assembly protects wearing area of the spiders. The caps are changed less frequent ly because of their size. Exclusive reinforcing tie bolts give secured support to the rotor to prevent expansion of the side end discs. Sleeves in the spider protect hammerpins and spider bores.

5. Top Grate - Provides additional throughput for TOP SECTION increased efficiency. 6. Fixed back Open Grate - This casting has openings for the product to pass and the tie bolts provide additional mid-section strength.

7. Upper front Breaker Wall - Utilizes an additional cutting edge in combination with the cutter bar. The castings are precision fit and tie bolted for additional structural support.

8. Housing - A thick reinforced extra heavy-duty housing provides a durable shell that is maintenance friendly. The sections are machined to give a precise fit. If a section wears, one has to replace only the worn section instead of replacing the whole housing. The sections are bolted together to eliminate welding and keep maintenance time to a minimum.

9. Hammers - The "Low Profile" design reduces ineffi cient counterbalancing weight. The result produces greater inertia and impact force throughout the life of the hammer.

10. Hydraulic Opening for Mid- and Top-section - These sections of the shredder hydraulically open for fast, BASE SECTION easy inspection and maintenance.

11. Hinged Arm Locking Link - Locks into position for safety when doing maintenance procedures or inspection. 12. Rugged Grate Design - Deep-section tangential manga nese steel grates are designed for longevity and the fast discharge of material. The unique design eliminates excess grate and hammer wear, while minimizing horsepower requirements. Consistent material density is achieved throughout the wear life. 13. Intake Spreader - It is positioned at the entrance of the shredder. The intake spreader bar absorbs the shock and abrasion of incoming material.

14. Anvil Backup - Provides a combination of one piec~ lower breaker bar, filler bar and six degree solid grate.· 15. Reversible Cutter Bar - The wide, thick cutter bar is designed to increase shredding efficiency by shearing the material in combination with hammers. The cutter bar is reversible for maximum life. Fig. V-11-2a A Svedala Hammermills shredder.

Wendt Corporation Close Dec., Ex. A r

Fig. V-11-2b. Isometric cross section view of a TSI 122/108 shredder

Fig. V-11-2c. The 122/108 disc rotor of a TSI shredder with recappable end discs.

SKETCHES BY COURTESY OF TEXAS SHREDDER INC., SAN ANTONIO, USA

Wendt Corporation Close Dec., Ex. A Fig. V-11-2d A 98104 TS[ Super Heavy Duty Shredder. Rotor speed is 475rpm and output 70-BOtph. PHOTO TAKEN AT FERS & METAUX, MONTREAL, CANADA, BY COURTESY OF TEXAS SHREDDER INC., SAN ANTONIO, TX, USA.

During the late 1950s Newell started to States later passed the 'Highway Beautifica shred steel scrap material to leach low tion Act', stimulated in particular by First copper containing ores for the copper Lady 'Ladybird' Johnson who supported mines using acid and steel scrap. One or a national campaign to make the U.S. two years later, Mr. Proler from Proler landscape wreck-free. Steel in Houston, Texas, began to sell some of his shredded steel scrap to Armco Steel Shortly after this, Luria Brothers, then the in Houston. major company in the U.S. scrap industry, Sam Proler was taught the shredding busi produced its own shredder; the product ness by LA.By-Products during World War was named 'Lurmet'. II at the request of the U.S. government, to Unlike current shredders, those early ma help the war effort. In 1955 Proler built a chines were not fed with flattened or other huge shredder and began to process vari wise prepared vehicles. Rather, the wreck ous types of material exclusively for the was dropped on to the rotor by a crane, as steel industry, producing what was then depicted in Fig.V-11-2. This put a heavy called 'Prolerized' scrap. strain on the rotor and the electric drive In that year, according to the calculations motor had to cope with large current surges. of the U.S. Environmental Protection Agency, there were no fewer than 14 million aban Therefore the earliest Proler and Luria doned automobile wrecks in the country. shredders needed extremely powerful They were dumped beside the roads or lay, motors, of around 4000hp, and production almost unsalable, in automobile junk yards. did not run smoothly. A fresh wreck had to Scrap values were low then, so the return wait until the previous one was fully was insufficient to cover transport and processed, and this led to huge variations processing costs. In short, no-one wanted in use of electric current. these wrecks. The shredded scrap was ejected through The federal government of the United a grate placed under the rotor; these first

Wendt Corporation Close Dec., Ex. A machines were therefore called bottom possible to shred complete automobiles discharge shredders. with their very strong - sometimes alloy Original shredders introduced in the early steel - components; for example, engines, 1960s used squirrel-cage AC motors gleaned gearboxes, springs, axles and differential from retired World War II merchant marine gears. vessels and diesel engines from submarines. It was an advantage that the non-metallics Universal Engineering Inc., now Svedala, were separated at the same time. This manufacturer of Hammermills shredders also compared with baling and shearing in produced a mobile shredding plant with which harmful dirt, but also the valuable a 1800hp diesel drive. non-ferrous metals, were often locked into the processed scrap. In 1959, Newell Industries built its first automobile shredder and began to sell The advantages of the shredder were made shredded scrap to the steel industry. possible by the combination of a fast This machine was the first to utilize the rotating heavy mass - rotors of perhaps limited feed feature and was a side feed, 25 tonnes each - and hard, wear-resistant top-discharge type of shredder, which was material in the hammers and wear plates or later patented. liners. Sceptics had declared that it would Subsequently Newell developed its own never be possible to shred an entire auto top and bottom grate arrangements, and mobile, but they were certainly proved introduced a reject door which is now wrong. a must for every such machine. It was a prerequisite that the shredder In the early 1960s, Universal Engineering Inc. 1 housings and rotors they contained, were sought a licence to build a Newell-type extremely strong and well-constructed. In shredding plant, but the negotiations were one well-known case, the wear plates had not fruitful. Then the company produced not been properly bolted inside a brand their first side-feed type of Hammermills new shredder. At the official inauguration shredder. of this machine, around 5 tonnes of scrap Hammermills licensed their bottom-dis was fed in but some 10 tonnes came out. charge system to Mitsubishi in Japan. However, this was not a 'miracle shredder', neither was there a 'miraculous catch of Newell Industries licensed Lindemann scrap', but rather the machine spat out the Maschinenfabrik GmbH 1 of Diisseldorf, quickly-loosened wear plates causing Germany, to build Newell-Lindemann a great deal of damage. shredders, an agreement which lasted for 13 years. An advantage of these heavy shredders was also that they could process the then Newell also licensed Fuji-Car Mfg. Co. Ltd - still - common automobile bundles, though to build its plants in Japan in the 1980s. with difficulty and as long as they were not Fuji-Car and Kawasaki Heavy Industries Ltd. too large or too densely compressed. and Morita, former Tezuka, are now the major Japanese shredder manufacturers. At the same time a few rippers or pre shredders were being built, machines de 11-B-3 COMPLETE AUTOMOBILES AND NON signed especially to tear apart the heavy FERROUS YIELD AS A BONUS (automobile) bundles; to avoid undue strain on the rotors (see Section 11-H). The achievement of the early shredder builders was that they showed it was It should be noted that the rippers of the time, which were still driven by a chain, 1 Note: Universal Engineering Hammermills of USA, were far less effective than the current Lindemann Maschinenfabrik and ORT, Oberlander of hydraulically driven machines, which have Germany were taken over by Svedala Industri A.B. of the additional advantage of being able to Sweden in 1996, 1997 and 1998 respectively. They are be stopped immediately and have their referred to in this book by their trade names Hammer direction of rotation changed when over mil/s, Lindemann and ORT, Oberlander. size material is fed in.

92 1111111111 Wendt Corporation Close Dec., Ex. A In Japan, where many automobiles are still Later there was the development of the baled or logged to facilitate transport from grate systems - top or bottom grates, some often cramped cities to distant shredders, times in combination, as in the Lindemann use of pre-shredders is common practice. 'Zerdirator'. The early shredders all dis charged through bottom grates only. Alton 11-B-4 SHREDDERS MAINLY FROM THE US, Newell designed a top discharge which GERMANY AND JAPAN was the original patented feature that differentiated Newell equipment from After building a few shredders, Proler and others. Until that patent ran out during the Luria stopped production, but soon other 1980s, every top discharge or top and companies applied themselves to the con bottom discharge shredder in the world struction of these machines and, in particu was licensed by Newell. lar, their improvement. They wanted in Most shredders built nowadays are TBD particular to dispense with extremely large - Top and Bottom Discharge - types. machines and also the system of dropping the wreck on to the rotor. Normally, the horizontal shredder rotor turns against the inflow of material and Lindemann, Henschel and (ORT) Becker (now chops it into pieces. ORT,Oberlander) in Germany, Newell In the 'Kondirator', developed by Linde Industries and Universal Engineering, as mann (Section 11-E-2), however, the rotor prominent producers of scrap processing turns the other way - along with and not machines in the Western World, could not against the scrap, as it were. lag behind in making shredders. They quickly applied themselves to the In this way long and/ or heavy scrap can be design of their own machines and regis cleaned without necessarily chopping it tered various patents which signified into pieces. After receiving hard knocks a considerable advance in technology and which remove dirt and concrete among efficiency. others, the long scrap passes from the rotor Shredders were also manufactured by, housing through a special kick-out door. among others, BJD in the UK - which later stopped production - Texas Shredder Inc. in Further improvements followed. One of the US, as well as Kawasaki and Fuji Car in the most important was the hydraulic Japan. Tezuka was also a major manufac 'clamshell' opening of the hood of the rotor turer of shredders, etc., but ceased produc housing (Figs. V-11-6a and V-11-9), com tion in 1994; it restarted operations in 1996 bined with alloy steel caps on, for example, under the name of Morita. the rotor discs (Fig. V-11-9). This made the continual nightly welding-on of worn Soon specialist manufacturers emerged to hammers and support discs no longer produce down-stream equipment, accesso necessary. Furthermore, axle-pullers made ries and spare parts. the replacement of hammers a simple task Some companies concentrate on complete of a few hours, whereas it took one or two dust collection or dedusting systems - e.g. days with the first generation of shredders. Osborn Engineering Inc. in USA, Venti-Oelde and Mikropul in Germany. Others produce Also, 'wet' shredders - see 11-F - were intro special conveyor belts, hydraulic drives duced, with the aim of precipitating the such as those for the feed roll(s) (Hagg dust of the crushed, non-metallic parts and lunds drives for instance), electric motors, removing it wet. This allowed the expen magnetic separation equipment, sieves, sive, energy-guzzling dust collection units shakers and oscillators. Then there are the to be dispensed with and reduced the manufacturers of non-ferrous sorting chance of explosions. systems, weighing equipment, and com puters for the control and automatic re An intermediate form - 'semi-wet' shredders cording of the performance of shredders. - also came on to the market, with the hope Spare parts producers provide a vast array of of removing problems with wet shredders, components including replacement ham such as water nuisance, frost sensitivity, mers, wear plates or liners, grates, breaker more wet waste disposal and loss of non- bars, rotor caps and complete rotors.. . ferrous metals. · Wendt Corporation Close Dec., Ex. A -

A 6---- l

6----

1 Feed rollers for controlled feed of 1 Treibrollen zur dosierten Rouleaux entraineurs pour dosage charged scrap Ma terialzufiihrung automatique de l'alimentation 2 Anvil for first tearing-off and 2 Ambol.s zum erstrnaligen 2 Enclume pour premier arrachement fragmentizing Zerreil.sen und Zerkleinern et dechiquetage 3 Baffle plate edge for further 3 Prallkante zur weiteren 3 Coin de rebondissement pour fragmentizing and pre- Zerkleinerung und Vorver- dechiquetage et compactage ulterieur compaction dichtung 4 Paroi de rebondissement pour 4 Baffle plate for controlled 4 Prallwand zur gezielten densification controllee compaction Verdichtung 5 Grille superieure pour sortie de la 5 Top grid for material discharge 5 Rostplatte zum Materialaustrag ferraille dechiquetee 6 Connection of dust extraction 6 Entstaubungsanschlul.s 6 Raccordement depoussierage system 7 Auswurftiir zum Auswurf nicht 7 Porte d'ejection pour grosses pieces 7 Ejection door for non-shreddable zer kleinerungsfahiger Grobteile imbroyables parts 8 Vibrationsforderer zum Material- 8 Convoyeur vibrant pour evacua- 8 Vibration conveyor for evacua- abzug tion de la ferraille dechiquetee tion of shredded material 9 Rostkorb zum Materialaustrag 9 Grille inferieure pour evacuation de 9 Bottom grid for material 10 Rostabdeckung zur Dichteregu- la ferraille dechiquetee discharge !ierung 10 Obturation grille superieure pour 10 Top grid cover for regulation of 11 Schwenkrost zur Dichteregulier- densification controlee density ung 11 Grille inclinable pour regulation de 11 Movable grid for regulation of la densite density Fig. V-11-3 A Standard Lindemann shredder (A) compared with a Lindemann Zerdirator, top-bottom discharge (B), installation. SKETCH BY COURTESY OF SVEDALA LINDEMANN . 94 .. Wendt Corporation Close Dec., Ex. A 11-C METHOD The hulks and other bulky scrap are placed on the conveyor by a front end loader, Like a coffee grinder, but usually in the a crane, or an excavator. The infeed conveyor horizontal plane, a shredder consists of is mechanically driven, generally at a fixed a clamshell casing, the rotor housing, with speed, or hydraulically driven at a variable a heavy rotor turning fast - usually around speed, see Fig. V-11-12 key number 2. 500-600rpm - inside it. First, the very fast swinging hammers 2 - A 'dosing' system, to feed the raw mate attached on an axle to the heavy steel discs rial gradually into the shredder. This is or spider arms of the rotor pulverise the a heavy feed roll or sometimes a multiple metal object against an alloy steel breaker (double or triple) feed roll. bar or anvil causing it to be fragmented or The earlier shredders had only a top roll to chopped into pieces. push the thereby flattened· car hulk gra Then the hammers drag the pieces of scrap dually into the machine. around the housing for as long as it takes to Later came a top plus a bottom roll, be become small enough to pass through the tween which the car hulk was crushed. holes in the grates. Newell Industries introduced a double1eed In the meantime the fragments of scrap roll system to overcome the problem of the · have been rubbed small and fine, cut or top /bottom roll twisting the car .hulk into grated between the hammers and the wear a 'banana' form. The feed roll or rolls are resistant inner plates of the rotor housing. now almost always driven hydraulically. If a piece of scrap does not immediately Hammermills originally introduced its own fragment, the hammer can deflect back and completely different system using an ward, away from the scrap. It might even apron-type compression feeder of the bounce all the way around 360 degrees, but crawler-tractor tread type, see Fig. V-11-3a. will always return to the extended position as long as the rotor revolves at high speed, 3 - The shredder or rotor housing, equipped thanks to centrifugal forces. inside with one or more anvil(s) or breaker The power is almost always provided by bar(s) and lined with alloy steel wear plates. electricity. But here the comparison with There is always a breaker bar positioned at the classic hand-driven or electric domestic the mouth of the shredder to absorb the coffee grinder ends, for the shredders used shock of the incoming material, generally in the recycling sector are giants. combined with a cutter bar (Figs. V-11-2 at The shredder rotor turns around a horizon 15 and V-11-3a at 6 and 7). tal axis, except in the case of the 'Henschel Furthermore there are grates and an emer Mills', of which only a few dozen are in use. gency - reject or kick-out - door for un Turnings crushers also often rotate around shreddables, thus eliminating potential a vertical axis, as do some cone rubble damage to the machine; and of course the crushers, see Section 11-L. massive rotor with its free swinging - often 360 degree reversible - alloy steel hammers. 11-D THE AUTOMOBILE SHREDDER The main electric motor, with a mechanical or hydrodynamic coupling - as is used widely in The modern autgrnobile shredder is Europe - drives the rotor but is installed a complete factory and in fact consists of outside the shredder housing. a group of connected machines. Beneath the shredder is a vibratory pan or Its product, shredded scrap, is highly oscillator, which receives the shredded regarded as, at around one tonne bulk material discharged through the grates and weight per cubic metre, it is compact, provides a uniform flow of scrap for down reasonably uniform in composition and stream processing. clean. In broad outline we can distinguish The shredder housing is of heavy construc the parts of the shredder as (see Figs. tion, of some 4 inches - or even thicker - V-11-lb, 2a, 3, 3a and 4): steel plate, and special liner plates. The liners in the main shredding area can 1 - A sloping loading/feeding chute, or 'feeder also be around 4 inches thick. device' often preceded by a slatted steel, hinged supply belt, or infeed conveyor using 4 - A double pressure-resistant shredder dust tracked or toothed rollers and chains. collection or dedusting unit. Initial dedusting

Wendt Corporation Close Dec., Ex. A Fig. V-11-3a An inside view in a 'Hammermills' shredder (the openable top of the rotor housing removed). 1. Compression feed device with crawler tractor tread type flights and ample hydraulic power combine to flatten automobiles or bulky scrap. 2. Capped rotor assembly. Cast steel end caps protect the wearing ends of the rotor spiders. 3. Reversible hammers. Following wear on one side, the hammers are reversed. When the second side wears, the hammer is moved to a new position and both sides are used again. No welding is ever required. 4. The massive rotor features over-sized anti-friction roller bearings to absorb shock, radial and thrust loads. 6. Intake breaker bar. Positioned at the mouth of the shredder, the intake bar absorbs the shock and abrasion of incoming material. 7. Reversible cutter bar. When one edge wears, the bars are simply turned upside down. When the second edge wears, the bar is reversed, and both sides are used again. 8. Deep-section manganese steel grates. SKETCH BY COURTESY OF SVEDALA HAMMERMILLS, CEDAR RAPIDS, USA.

often takes place in the top, - or also at the unit works with 'wet' and 'dry' dedusting bottom, Fig. V-11-4 - of the rotor housing, cyclones and venturi scrubbers. and generally has a capacity of between The light particles, removed from the scrap 25,000 and 80,000 cubic metres per hour. in the shredding process, are sucked into There is usually a second dedusting system the dust collection unit and expelled above the outflow and/ or non-ferrous belt, through an airlock. Some 80 percent of the with a capacity of around 40,000-150,000 cleaned air is recirculated to the dedusting cubic metres per hour. The dust collection system and the remaining 20 percent goes 96 .. Wendt Corporation Close Dec., Ex. A to the wet scrubber so that wet dust does concrete foundations, cut wear on welds not accumulate in the separation unit. and can reduce or even avoid vibrations that might otherwise be transmitted through 5 - Outflow (outfeed) belts with vibratory the ground over extended distances. screen(s) and/ or oscillator and/ or screening Some shredders stand on rubber blocks or drum, as well as vibrator or conveyor-fed hydraulically dampened springs. drum magnet(s), overband magnet(s), for magnetic separation, non-ferrous sorting 7 - An elevated control cabin - with pro belts and a swivelling radial stacker of va tected, impact-resistant, windows - and rious lengths for storage or direct loading including the command console with the of the ferrous scrap, Fig. V-11-lb at 13. various control instruments and operating buttons. This shredded scrap will be delivered into containers, trucks, railway wagons or ships As mentioned above, almost all shredder or stockpiled on a hard (concrete) surface. rotors are driven electrically. But there are Several of these accessories are described in also 20 to 35 electric motors incorporated in Chapter VI, or as sorting/separating equip the total concept, which drive compaction ment in Chapter VIL rolls, the many conveyor belts, drum magnets and dust collection unit. 6 - Vibration dampeners installed under the shredder (see for instance Fig. V-ll-9c) will Shredders are generally classified by make significantly reduce the need for expensive and by horsepower or kilowatt-hours of

Fig. V-11-4 The Kawasaki shredder has a slightly different concept and is available in five types varying from 325 to 2500hp. 1. Long hammer. 2. Short hammer. 3. Bottom discharge grate with oblique openings. 4. Top grate. 5. Bottom dedusting channel. 6. Hollow wear plate generating ball-shaped shredded scrap. 7. Emergency ejection door. 8. Two independent hydraulically-driven feeder rolls. ILLUSTRATION BY COURTESY OF KAWASAKI HEAVY INDUSTRIES, TOKYO/KOBE, JAPAN.

-- Wendt Corporation Close Dec., Ex. A the main motor. Remember that 1 hp = generally far smaller, often consist of little 0.7355 kWh. more than a cutting rotor within its hous In the US, however, they are generally ing, and a hopper. classified by size, see 11-A. 11-D-1 FEED AND TYPES, COSTS AND It must be added that the above enumera PERSONNEL tion of the parts of the shredder (1-6) applies particularly to automobile/metal When members of the recycling industry shredders and some rubble crushers, speak of shredders they often mean the although the latter often lack the otherwise automobile shredder. Given that these characteristic dust collection cyclones, and machines can swallow complete auto generally in the 300 to 700hp range of mobiles in one go and chop them into driving power. See Section 11-L. small, fist-size, chunks of metal, they are very large, integrated machines which The remaining shredders and crushers, must be constructed to be extremely such as office paper shredders, which are strong.

Fig. V-11-5 The TBD - Top/Bottom Discharge - Zerdirator. A special feature of the Zerdirator is the lid (7) which can close the top grate so that the scrap remains in the rotor housing longer and thus becomes more dense. 1. Feeder roll(s). 2. Rotor housing. 3. Anvil. 4. Baffle plate edge for further fragmentation and pre-compression. 5. Baffle plate, an important means of achieving the required density. 6. Top and bottom grates. 7. Top lid can be closed if required. 8. Emergency ejection door. 9. Duct to dust collection unit. ILLUSTRATION BY COURTESY OF SVEDALA LINDEMANN.

98 .. Wendt Corporation Close Dec., Ex. A In practice, feedstock consists not only of Modern shredders also have automatic old automobiles, but also of much light recording systems, mostly for input and scrap such as bicycles, office furniture, soft output weights and power consumption. drink vending machines - especially in The total operating personnel, including Japan! - and many domestic appliances maintenance, but excluding administration consisting of so-called 'white' goods and truck drivers, varies between around (refrigerators, stoves, washing machines five and fifteen people. etc.) and sometimes also 'brown' goods (TV sets and radios). 11-D-2 AUTOMOBILE SHREDDER-PROCESS By scaling-up, applied particularly since DESCRIPTION the 1980s, much heavier (# 1) scrap, such as rolled sections and truck scrap, can now The route which an object to be shredded also be shredded. follows, can be traced with the help of the The smallest types of automobile shredders diagram (Figs. V-11-la and lb). generally do not process complete, but rather pre-cut, automobile wrecks and start a The input or feed at around 500hp. The most common shredders in Europe are After being weighed, incoming old auto in the range of around 1000 to 2000hp, in mobiles are usually stacked in large piles. the US over 2000hp. With a capacity of an automobile per The largest types are classified differently, minute or more, modern shredders clearly but especially in Europe, operators discern require a continuously replenished stock of 'heavy-duty' shredders as between 2000 raw material. and 3000hp. The area above that is custom arily described as 'super heavy-duty'. Inspection prior to shredding has become However, it is generally the shredder increasingly necessary, even mandatory, manufacturers themselves who introduce particularly when the following items have and use these concepts. In the US the not been removed by the dismantler or largest machines are also known as 'mega' shredders. Fig. V-11-6a A smaller type of shredder opened for A complete automobile shredder installa inspection. tion, with dust collection unit, motor A: Driving belts connecting motor to main shaft. housing, conveyor systems, foundations B: Hydraulic - Hagglunds - drive for the feed roll (C). etc. weighs several hundred tonnes and D: Hydraulic cylinder for 'clamshell' opening of the averages between $2.5 million and (some rotor housing. times well over) $5 million in cost. E: Upper part of the rotor housing. In addition, hundreds of thousands, if not F: Hydraulic drive for operating the emergency door millions, of dollars are often spent on feed (G). conveyors, noise abatement and environ H: Wearplates behind the side grate (I). mental measures, on non-ferrous and J: The spider-type rotor. rubber separation systems, front-end K: Hammer wear-caps. loaders or shovels, excavators, cranes and trucks.

Then there are the infrastructural elements, such as non-permeable surfaces and storage floors with oil separation and/ or waste water treatment installations (for 'wet' shredders), rail connections, embankments, maintenance warehouses, pre-inspection installations (to remove gasoline and avoid explosions), weighbridges, axle pullers (hydraulic feederdrive - headshaft and hammerbolt - puller) and spare parts. A further enumeration is to be found in 11-G, 'Accessories and peripherals'

Wendt Corporation Close Dec., Ex. A owner (as shredder operators in the US and It has also been shown that murderers various other countries require): sometimes even use automobile wrecks to ensure the total disappearance of victims. - easily flammable and explosive sub In various other countries this has proved stances: particularly gasoline in the tank to work only too well. In a 'shredder liqui and possibly LPG or LNG tanks. Some dation' case in The Netherlands a few years times also the airbag inflation capsule. ago, the police could not trace more of the victim than his gold teeth. - other liquids, such as anti-freeze or ammonia (in the air conditioner) which can Inspection consists of the opening of the cause environmental problems trunk/boot and emptying the gasoline tank by sucking or punching a hole in it; to this - excessively heavy parts which could end there is a special 'tank piercer' (see Fig. damage the rotor, the liners and their Vl-5-3) which also ensures that the gasoline housing or diesel fuel is collected.

- 'hidden' irregularities - whether delibe If gasoline and other fluids are to be tapped rate or not - in the automobile wreck, such off, the bottom of the vehicle must be made as old tyres, old batteries, domestic and accessible. So the automobile is either other waste (to avoid dumping and remo simply lifted by crane or front-end loader, val costs, but more importantly, to add or set on a rising platform - comparable to weight). the hydraulic lift in a garage - or else posi-

Fig. V-11-6b Anna Kroesemeijer is proud of this new SPIDER ROTOR, with a weight of 20 tonnes. Note the 10 PIN PROTECTORS lying between two bell-shaped hammers. The spider arms are protected by hard steel or manganese steel caps (13 here). The small ears welded on the caps are for lifting purposes only. PHOTO BY COURTESY OF PAMETEX, THE HAGUE, THE NETHERLANDS .

100 .. Wendt Corporation Close Dec., Ex. A tioned on a hydraulic ramp or a 'tilting shredders have double top rolls, which platform'. See also Figs. VI-5-1 and 2 and a hydraulic system keeps in position as if VII-6-A. on a spring. They steadily flatten the wreck and project it into the shredder. In some The separate tapping-off of all the liquids newer shredders the rolls, which naturally by the dismantler or by the shredder opera turn very slowly and often at a variable tor is quite a task, for there are generally speed, are driven hydraulically. many different fluids which cannot be The direction of rotation can usually be mixed if they are to be re-used. reversed.

The various automobile liquids include: The input roll system has two advantages:

- cooling water with anti-freeze - the squashing action means that the - windscreen spray, with cleaner and/ or infeed opening of the shredder can be anti-freeze relatively small, reducing the risk of lumps - gasoline/diesel/LPG/LNG of scrap being flung from it. - gearbox oil - with its free-swinging hammers, the rotor - brake oil will have less difficulty in 'nibbling off' the - suspension oil (in the shock-absorbers) wreck. - differential gear oil - hydraulic oil, for power braking and Hammermills introduced a special compres steering sion feed device. It has rugged, crawler tractor tread type devices which flatten It is also possible that liquid - usually automobiles with ample hydraulic power ammonia and CFCs - has to be tapped from (Fig. V-11-3a). the air conditioner. Those who deliver refrigerators to shred b Shredding der plants are expected to have removed any CFCs from the cooling system and the The shredder rotor shown in the diagram insulation. (V-11-3) rotates against the scrap being fed. Thus the hammers on the rotor tear pieces The automobile or other object to be shred of scrap from the raw material as soon as it ded, is lifted by crane on to an often tiltable enters the shredder housing. loading chute. The hammers first rip the flattened auto Many current shredders, however, have an mobile against the breaker bar or anvil inclined infeed or apron feeder conveyor positioned at the mouth of the shredder. belt around 2 metres wide, on which the Hammermills also has a reversible hydrauli automobiles are placed by loader or crane. cally moved cutter bar. Normally this belt is made of hinged steel slats, and brings the wrecks on to the The breaker bar is usually bolted fast to the loading chute. Fig. V-11-la. shredder housing. However, a modern variation is for the anvil and/ or breaker The supply belt sometimes has a horizontal bar - or multiple breaker bars as in the section before rising at an angle, especially Kondirator - to be movable in the shredder when pre-shredders are being used, or housing. The anvil or breaker bar can then with very large shredders, where four or be hydraulically moved in and out, thus more cranes or shovels may be necessary to varying the distance to the scrap, which feed sufficient material. obviously has an effect on the dimensions From the control or command cabin the speed of the raw material. of the input belt (especially those with The anvil/breaker bar absorbs the shock hydraulic drive) can be varied. and abrasion of incoming material.

Shredders generally have a hydraulic feed The scrap is subsequently dragged deeper roll (or double or triple rolls) which flatten into the rotor housing by the hammers, and the raw material and literally propel it into the fragments are further reduced in size the rotor housing. between the hammers and the rotor housing As described earlier, Newell Industries Inc. wall and cast steel grates until they are

101

Wendt Corporation Close Dec., Ex. A Fig. V-11-7 The size of these 12 hammers - weighing Fig. V-11-8 The same hammers, worn-out after 190kg each - for a 5000hp Zerdirator can be judged shredding some 5000 tonnes of steel scrap. Note the from the safety helmet placed on one of them. protective caps top left. PHOTOS 7 AND 8 TAKEN BY THE AUTHOR AT THE MPR SHREDDER AT WILLESDEN, LONDON.

small enough to be knocked through the which weigh between 50 and 400kg each. holes in the grates. These items are general The hammers are made of manganese or ly made of manganese or other alloy steel. other alloy steel, but due to heavy impact on the scrap, they are still susceptible to An interesting feature can be seen in the heavy wear and tear. Figs. V-ll-6b, 7 and 8. Kawasaki shredder (see Fig. V-11-4) where the wear plates beside the lower grate are Newell Industries has calculated that 'hollow' - mountains and valleys, so to hammer wear is in direct correlation to the speak - thus causing the scrap to be rubbed amount of production. Newell estimates to a ball shape, which is particularly dense. that half a pound - about 225 grams - of wear occurs per tonne of scrap produced. Pieces which are too large and might block A hammer is usually worn out after the shredder are ejected via a kick-out or processing some 2000 to 3000 tonnes of emergency door. This vertical door, usually scrap. located on the upper rear hood of the shredder, is activated hydraulically by the Newell states that in its shredders the total operator. Hammermills shredders, how amount of casting that must be purchased, ever, have a horizontal kick-out door. will be about 2.2 lb per gross tonne shred It is also possible for the kick-out door to be ded (stated another way, it will take about opened automatically whenever over 1kg to shred one metric ton of finished steel weight scrap is fed in. scrap). While the wear rate is almost the An experienced operator instantly recog same in all shredders, some are designed nizes by the 'rattling' of the shredder that with a view to reducing the amount of an oversize or too solid piece of scrap casting that is worn away. threatens to block the rotor. Newell also remarks that the wear rate of a hammer has more to do with the total There are mainly two types of rotors: weight of the hammer than with the horse (capped) disc design rotors, see Figs. power of the unit. For example, in the V-ll-2c and 9, and (capped) spider type 80104 SHD shredder the hammer weighs rotors, see Figs. V-ll-2a, 3a, 6a and 6b. about 330 lb and a set of 10 lasts for about 3000 to 3500 tonnes of production when The rotor consists of a heavy shaft with a producing normal densities of shredded number of very thick steel discs or arms scrap. A further example is that the 98104 (spider rotor) on it. There are holes in these SHD has a hammer that weighs about twice through which pass the steel axles to which as much and a set of 10 produces about the hammers are attached. They are gene twice as many tonnes before they wear out. rally called hammer pins. There are often 12 of these, but sometimes Following wear on one side, the hammers up to 36, generally bell-shaped, hammers are reversed. When the second side of the 102 ... Wendt Corporation Close Dec., Ex. A bell-shaped hammer wears, it is moved to The many wear plates forming the inner a new position and both sides can be used lining of the shredder housing, the grates again. and the breaker bar, and/ or other anvils, can also be changed. The socket-head bolts The discs or arms, between which the which secure these parts are recessed so hammers are freely suspended, are often that they cannot be damaged by scrap protected by alloy steel caps, which prevent being pounded in the mill. excessive wear to the outer rims. In the past, the disc rims and hammers had to be In various Newell shredders, the axles - or rebuilt by regular welding almost 'pins' - between the heavy discs are guard nightly; nowadays this is no longer neces ed by toothed wheels called 'pin-protectors' sary (Figs. V-11-6a, 6b and 9). (Fig. V-11-6b). Newell Industries Inc. and TSI use pin The caps are changed after a certain protectors on all their disc design rotors and number of hours of operation; so are the on all spider types they build. The pin protec hammers or, as mentioned above, they are tors are used wherever hammers can be turned round. fitted, but where they are not being fitted in the particular hammer arrangement. This allows hammers to be moved around the Fig. V-11-9: A look into the 5000hp SHD Zerdirator rotor to new positions as the rotors wears. in Willesden, London. If the rotor is a 'capped disc' type, such as Note the man working at the wear plates, and the top that made by Lindemann, the pin protector grid, now in vertical position. At X, a hammer hanging is not used. In capped spider type rotors, from its axle (pin); Y, the rotor discs are invisible as however, the pin protectors can be used. they are protected by disc-caps as at Z. This rotor weighs no less than 58 tonnes and has a diameter of As mentioned earlier, there is a whole 250cm. The width of the rotor housing is 286cm. range of different types of rotor available. PHOTO TAKEN AT MPR IN WILLESDEN UK. Newell Industries, for instance, offers at least four alternatives: a 'battle' rotor, a 'disc' rotor, a 'capped disc' rotor with 4in thick discs, and a 'spider' type rotor with so-called 'football-helmet' type caps. The Japanese Kawasaki shredder features long and short hammers alternately (Fig. V-11-4 at (1) and (2).

In many modern shredders the heavy axles or 'pins' from which the hammers are suspended, can be removed from the rotor with the aid of a heavy hydraulic drive, hammerbolt or axle puller, so that changing the hammers can be achieved in a matter of hours (Figs. V-11-la and lb).

Many common rotors have six axles with two to four hammers each. Usually two or three axles with their hammers are re placed per 'session'; in the next session the other three or four axles are changed. An experienced team changes a set of six hammers in an hour to an hour and a half.

Newell medium-size shredders, and other types that are similar to the Newell design, use 10 or 12 hammers. Hammermills' machines usually use up to 34 hammers. The rotor, with the main shaft protruding

103

Wendt Corporation Close Dec., Ex. A from the rotor housing, is supported in two In the Henschel mill the direction of rota heavy bushes. The Newell 'Mega' shredder tion can be reversed by changing the pola has 18-inch rotor bearings. rity of the drive.

If the rotor is blocked its bearings are in Shredded scrap is discharged through the danger of being lifted or even snapped off. grates under the rotor to a vibratory outfeed Lindemann has recently solved this prob located beneath the discharge hopper. lem by making the bearings hydraulically This can be of the oscillator type or an movable. When a blockage is imminent the eccentric weight vibratory unit. bearings are lifted upward and backward, The whole shredder housing is mounted on giving extra space for the threatening piece anti-vibration devices, consisting of springs of scrap to pass. and/ or a hydraulic damper system to reduce shock and vibration, which are Since its housing consists of two hinged major causes of wear and fatigue. main parts - top and bottom - the shredder An important reason, however, why shred can be opened up like a clamshell, giving der operators install a spring and damper access to the rotor. system is to prevent vibrations from travel All modern shredders have a hydraulic ling through the earth and affecting nearby system allowing the upper housing to be structures or people. So this is done for lifted open for easy inspection and mainte environmental considerations. nance, as can be seen on Figs. V-11-6a and 9. Sometimes only rubber dampers or just Powerful hydraulic rams open the upper steel coil springs are used. back section in minutes to expose the complete rotor and hammer assembly. The vibratory outfeed, or feeder, under the shredder has to be reinforced with robust In this way, the alloy steel liners or wear impact- and abrasive-resistent liners, as it plates lining the inside of the rotor housing, must withstand explosions in the shredder can also be changed. Hammers, grates, housing, and as shredded scrap is ejected breaker bar or anvil and wear plates are through the grate system at speeds of over usually made of manganese steel (12-14 150mph and distances of 5-lOft. percent manganese); this is generally further alloyed with chromium, nickel, The space above the upper grate (see vanadium and molybdenum, for example. Figs. V-11-3, 4 and 5), also known as the 'hood' of the shredder, will be occupied An additional advantage of being able to by two essentially different material open the upper housing is that the rotor can fractions. be lifted out in its entirety, after the bearings First there is the heavy fraction consisting of of the main shaft have been loosened. Thus shredded ferrous and non-ferrous metals the rotor can be swiftly replaced, and liners and some heavy non-metallic materials and grates can be inspected, repaired, or such as larger pieces of tyre. renewed. Second is a light fraction consisting of paint, plastics, road dirt, glass fragments, rubber, Many shredders, in Japan in particular, have textiles, wood splinters, etc., as well as the a bridge crane over the rotor housing to lift smoke/ steam of burned or evaporated out the rotor or smaller parts such as ham liquids. This is the fraction which will be mers and grids. Rotors can be very heavy; sucked-off in the dust collection. system. that of a SHD SOOOhp Lindemann Zerdira If there is only a lower grid this material tor - as can be found in Willesden, near must be sucked-off after leaving from the London, for example - weighs no less than shredder. 58 tonnes, having a diameter of 2.50 metres; it rotates in a housing 2.86 metres wide. With TBD (Top Bottom Discharge) shredders, The shredder housing's all-welded plate Section 11-E-1, of which the Zerdirator is - up to 6 inches thick - construction is an example, the scrap is knocked through sometimes, as in the TSI, Texas Shredder Inc. the upper and lower grates, the perfora unit, stress-relieved by high-frequency tions in the lower grate sometimes being vibration so that it will be free from any smaller than those of the upper. In the tendency to warp or suffer cracked welds. 2500hp Zerdirator the 'mesh' of the upper 104 .. Wendt Corporation Close Dec., Ex. A grid is 180 x 160mm wide, that of the lower There are various means of capturing the grid 100 x 150mm. Dedusting occurs above emissions which are given off as particulate the upper grid, sometimes also beside or and blue smoke generated from water below the lower grate. vapour and hydro-carbons.

c The dust collection system Friction generated in the mill can ignite oil and gasoline residues. In fact the tempera The shredder dust collection system is the ture in the rotor housing can rise to about first unit of the downstream process. 60°C and higher. This is the largest part of a shredder instal Mixtures of gasoline vapour and dust can lation with its high cyclones, which is what and sometimes do explode, and to prevent the visitor notices particularly when seeing this shattering the dust extraction unit a shredder for the first time. - which has occurred many times in the past - there are now various explosion relief Dust collection systems are added to ex hatches in the system. tract dust and smoke and small, light non Furthermore, modern cyclones are built to metallic particles, and to guard against be pressure-resistant. explosions. They draw out most of the dust generated throughout the machine, starting The shredder itself is strong enough to with the infeed beneath the feed rolls. absorb these explosions, although the housing is sometimes equipped with Thus all emissions will be captured and air explosion relief hatches. pollution requirements met. Additionally, it is possible to inject water The dust extraction unit often includes I into the shredder housing to suppress dust, a cyclonic or venturi scrubber using water see Section 11-F, 'wet shredders'. to 'scrub' the dust and fumes, the residue

Fig. V-11-9a The 98104 Newell shredder in Sweden. The diameter of the hammer circle inside the shredder is 98in, the effective width of the shredder opening is 104in. PHOTO BY COURTESY OF NEWELL INDUSTRIES INC., TAKEN AT STENA BILFRAG IN SWEDEN. l {

105

Wendt Corporation Close Dec., Ex. A Fig. V-11-9b The feed roll crushes and flattens bulky scrap. PHOTO BY COURTESY OF NEWELL INDUSTRIES INC.

then being transferred to a sump often metals slide back to the feed end for dis located in an adjacent pit. charge. This rotating metal cleaning trammel Sometimes nitrogen capsules were used as screen can be used before or after magnetic explosion dampers in the upper housing. separation (Fig. V-11-lb at 10 and 19). Usually the trommel has an internal helical There are also high speed explosion sensors flange to ensure the efficient separation which activate water injection into the dust and transfer of material to the outlet. collection system may be used to suppress or avoid explosions. The same principle applies to the cascade or zig-zag separator or cleaner using an upward d The heavy metallic fraction air flow in the opposite direction of the material flow. The heavy fraction which is deposited on As the scrap drops, the lighter waste mate a vibratory or oscillating outfeed conveyor rial is entrained in, the air stream and under the shredder housing, continues on removed. its way via a, usually upward, conveyor belt which brings this metal/non-metal mixture In most cases this system employs a cy into the cleaning system. clone, a fan and a rotary valve. The metals Generally, there are two air-powered can be fed directly to the magnetic separa closed loop systems to remove lightweight tor unit via a cascade chamber. debris, dirt and dust contamination from Newell Industries Inc. has designed a new ferrous and non-ferrous metals. zig-zag unit that features a drop-out chamber immediately next to the separation cham One system works with a large rotating ber known popularly as a Z-box cleaning trammel screen that is mounted at an incline scrap with forced air, while reducing of roughly 10 percent. emissions and horsepower requirements. A stream of air passes through the trommel, The waste material is removed from the air picks up the lightweight debris and blows it stream and does not have to travel through upwards to the opposite end. The heavier the ductwork and cyclones.

106

Wendt Corporation Close Dec., Ex. A Sometimes a special cooling scrap1 separa Sometimes a belt scale is installed on the tion drum is interposed to make this highly radial stacker to weigh the product before specific type of premium scrap. it is discharged. Also some shredders still incorporate a rubber separation device which uses friction Subsequent sorting of this scrap reduces the to separate rubber from glass, metal and critical copper content, for combinations of stone. These vibration sorters are, however, ferrous and non-ferrous metals may be now gradually being replaced by modern picked up by the magnet and mixed with eddy current separators (Chapter VII). the ferrous material. There are many electric motors in an automobile - starter, When the shredded scrap has been pro dynamo, windshield wiper motor, auto cessed through the trommel (drum) or matic door and window openers, for in cascade cleaning system, the heavy fraction stance - in which the soft iron armatures is discharged to a transfer conveyor for are wound with copper wire. This bond is delivery to the magnetic separation unit. so strong and the electric motors are often This can consist of one or two permanent so small, that the copper may not have or electro-magnetic drum units. been separated from the iron in the shred der. As copper is one of the worst contami An eddy current separator - as described in nants of steel scrap and can make it unac chapter VII-6-B - can be placed here as well ceptable to the steel mills, these motors or to eliminate non-metallics, but this ma armatures and other iron-copper combina chine is mostly employed away from the tions must be fished out by hand. main shredder installation. European integrated steel mills do not generally wish to receive scrap in which Drum magnets draw iron and steel scrap the copper content is above 0.20 percent; from the heavy fraction and deposit it on for many the limit is 0.15 percent, a propor a ferrous picking conveyor or straight to tion that cannot generally be reached when a radial stacker conveyor. This elevated shredding automobiles and post-consumer conveyor is mounted on an undercarriage, goods. In countries where the primary sometimes with motorized wheels, and product is reinforcing steel for concrete in pivots through, usually 180, degrees low-rise construction, a copper content of (Figs. V-11-la and lb). around 0.25 percent is usually considered acceptable. At many shredder installations the scrap is fed directly from this stacker into rail wa There can be other undesirable combina gons or gondolas, ships, containers or trucks. tions .of magnetic/non-magnetic materials, Alternatively it may be stacked on the such as pieces of tyre in which steel has ground, as shown on. Figs. V-11-la and lb. been bonded tightly to the rubber and attracted to the magnet. These items are The latest shredders incorporate sensors on sorted by hand-picking on the final ferrous this final conveyor, which control motor belt, by means of a gangway alongside this ized hydraulic raising and lowering cylin radial stacker, or, as stated above, on ders that keep the delivery height as low as a special ferrous picking conveyor. possible, minimising noise and dust. e The non-magnetic fraction and shredder waste/ Most shredder operators employ one or fluff more workers to handpick on the ferrous picking conveyor or on the radial stacker The heavy non-magnetic fraction is left for the purpose of removing entrapped untouched by the drum magnets and is non-ferrous material, mostly copper wiring often removed laterally for further separa entangled in the ferrous fraction, or other tion on the non1errous sorting belt. waste material, such as carpeting, uphol stery, tyre pieces etc. Newell Industries calculates that non-ferrous metals recovery in North America amounts to around 2 to 3.25 tonnes per 100 tonnes of 1 Cooling scrap is used as a high-quality feed in BOF shredded steel scrap produced. furnaces as it' is very dense and generally very clean. In Europe, Newell indicates, 4 tonnes of

107

Wendt Corporation Close Dec., Ex. A non-ferrous metal is generated per But it must not be too wet, as this would 100 tonnes of shredded steel. make the transport and dumping costs Our experience, however, is that these even higher, and further complicate the percentages depend on the thoroughness of possible separation of any remaining the vehicle dismantlers' work, as they often fragments of metal in the dust. remove batteries, radiators and catalytic converters. In brief: items with a high non The shredder fluff conveyor transfers this ferrous or precious metals content. Besides, material to a bunker or directly into con the composition of the shredder infeed has tainers for removal to a landfill site, or for materially changed in recent years. some other purpose eg, as fuel. Emphasis is more and more on domestic Any residual iron is often removed from appliances discards - 'white' and 'brown' the shredder fluff with the aid of overband goods in general - and light steel construc magnets. Non-ferrous metals still present tions. are recovered with the aid of an eddy current installation. In countries where coins are non-magnetic - as for instance in Germany - shredder The dust collecion unit is driven by fairly operators may recover the equivalent of powerful electric motors and the entire more than DM 1 in copper or silver coins dedusting system requires a relatively per car shredded. Bearing in mind that large amount of energy, sometimes more a big automobile shredder can process tens than 500hp. of thousands of old cars a year, this can provide the shredder operator with But one should bear in mind that thousands a welcome bonus. of tonnes of light fraction have to be sucked This sorting of coins used to take place by away over quite a considerable distance. hand, but is now usually done mechani Furthermore the aim is that ultimately no cally. more than 20-30mg of dust remains per cubic metre of air after separation. First, the non-ferrous fraction is screened, often into four different streams: under Note that the power of a shredder installation, 12mm, 12-50mm, 50-lOOmm and over expressed in horsepower or kilowatt-hours, 100mm. The 12-lOOmm fraction is some only represents the power exerted on the rotor. times replaced by an over-65mm fraction. Thus the total power of a '1250hp shredder' is All this is achieved with trammels. considerably higher, thanks to the many other In Japan, that part of the glass fraction electric motors - from 15 to 40 - involved in the which has not been drawn off by the dust whole installation. collection systems, is also often screened off separately. 11-E OTHER TYPES. ZERDIRATORS, The separation of the non-ferrous fraction KONDIRATORS AND MILLS; HD AND is further described in Chapter VII, where SHD SHREDDERS identification, sorting and separation with 'dry' and 'wet' techniques are discussed. 'Zerdirator' and 'Kondirator' are brand names of Lindemann, Diisseldorf. The Finally there is the shredder dust or waste 'Henschel Mill' is the small vertical shredder fraction, also called 'shredder fluff. of Henschel in Kassel. The terms 'Heavy As described, this is generated at the two Duty' (HD), 'Super Heavy Duty' (SHD) or dedusting units, in the shredder housing, 'Mega' shredder can be freely used to above the conveyor belt just before the describe the larger types of shredder. separation drum, and possibly at the non Note also that a Zerdirator can be an HD or ferrous sorting stage. SHD shredder, too, as in the case of the The shredder fluff which has been extracted previously mentioned 5000hp Zerdirator at and collected in the cyclones falls from the Willesden, London. dust collection unit on to a special conveyor belt. 11-E-1 THE ZERDIRATOR

This dust fraction has been dampened in Top-bottom discharge (TBD) shredders are the cyclones so that it does not blow away. now common types and are distinguished

108

Wendt Corporation Close Dec., Ex. A by grates both above and below the rotor. This can be clearly seen from the two small Lindemann call these shredders a 'Zerdira Zerdirators in The Netherlands. There is tor', which are available in the range of 500 a 750hp Zerdirator at the Hoogovens to 750 and up to 6,000hp. steelworks in IJmuiden to process its own Typically, a Zerdirator has a tilting lid 'home' scrap in the form of chips to cooling above the upper grates. When closed the scrap. It is run by Heckett, which also re shredded scrap will leave the shredder processes the steel slag and pig skulls of housing only via the lower grate and thus this large steel company. It will be clear will remain in the mill for a longer period. that the mesh-size of the grates of a 'cooling When a Zerdirator is used for aluminium scrap shredder' is kept relatively small. shredding, the top grate is closed for this purpose. A lOOOhp Zerdirator can be found at A VR, the world's largest waste incinerator, in the The double grate of TBD shredders enables western dock area of Rotterdam. From scrap to be passed out a little more easily. 1 million tonnes of domestic and industrial Of course the manufacturer can make the waste burned there annually, around mesh size of the grates as large or as small 200,000 tonnes of incinerator slag is passed as it likes. through the Zerdirator for the iron to be removed, after which this ferrous fraction, It should be clear that a smaller mesh will with many cans, bottle tops, nails, etc., is keep the scrap in the machine somewhat shredded, yielding some 20,000 tonnes per longer, with the consequence that it will be annum. This Zerdirator was installed at the smaller, denser, and generally cleaner. In end of the 1980s and still works satisfactori short, the mesh can be adjusted to the type ly. In the meantime five other operators of of product desired or to the type of product incineration plants in The Netherlands have being processed . bought similar, but smaller units, of 500hp. . . . l Fig. V-11-9c The Kondirator. 1. The tilting feeder chute is a machine in itself 2. The toothed upper feeder roll . 3. The lower roll. 4. A hydraulically operated lid compresses the bulky scrap. 5. Anvil. 6. Rotor with hammers. 7. Emergency ejection door with anvil in closed position. 8. Grate. 9. Movable anvil. After compression by the feeder rolls, the complete feeder unit is lowered (5 lowers to 6), the scrap is caught by the rotor which turns anti-clockwise, is impacted against the anvils and ripped apart. Note: the vibration dampeners beneath the frame. ILLUSTRATION BY COURTESY OF LINDEMANN.

109

Wendt Corporation Close Dec., Ex. A 11-E-2 THE KONDIRATOR ward but upward, the first anvil or breaker bar which has to absorb the initial shock is A real departure from the norm is the attached to the top of the loading chute concept of the Kondirator, another Linde rather than to the shredder housing, like mann product. Kondirators can also be a normal shredder or Zerdirator. found in the range of 1000 to 4000hp, but But a Kondirator has another two anvils, i.e. the system and application are completely one on the kick-out door I grid and a third different. at the bottom of the rotor housing. All three of these anvils can be moved hydraulically. The Kondirator was developed from the desire to shred scrap other than the tradi In two earlier, smaller, types of Kondirator tional old automobiles and white and there was a side-press installation attached brown goods, but particularly longer and to the loading chute with its integrated heavier objects, such as beams and pipes. input rolls. The chutes are now so wide, however, that this is no longer necessary. Long heavy beams or alloy steel (drilling) They can also be tilted into the vertical pipes cannot be fed into normal automobile position (see Fig. V-ll-9c). shredders or Zerdirators. If the hammers do not shred this material immediately it enters 11-E-3 THE HENSCHEL MILL the shredder house, the consequences could be disastrous. The Henschel mill employs the principle of A heavy, oversize object blocks the rotor, the turnings crusher, adapted for larger as it cannot pass between this and the rotor scrap. Henschel builds these machines with housing, so something has to give way. power ratings of 250-750hp. Complete The kick-out emergency door cannot yet be automobiles cannot be processed in these reached, as it is on the other side from the mills, but must first be cut into pieces of at input, so there is no relief there. most 150cm length by 100-120cm width. Understandably the 20-25 tonne rotor Usually this cutting is by a hydraulic guil rotating at roughly 400-600rpm cannot be lotine shear, but a ripper or pre-shredder, stopped abruptly. Even if it does not break, Section 11-H, will also suffice. there is a strong possibility it will be lifted As mentioned earlier, the mills can be seen from its bearings. as very large coffee grinders, with the axle The damage can easily run into hundreds of rotating in the vertical plane. thousands of dollars and the plant will be The scrap to be shredded drops from top to out of operation for some time. bottom, and is then ejected. There is no grate in these mills. The Kondirator solution is as simple as it is The rotor is slightly conical. There are three logical. The rotor turns the other way; the or four discs on the vertical shaft to which hammers do not knock 'against' the scrap, the axles of the 'hammers' are attached. but 'along with' it; the speed of the rotor is But, just as with turnings crushers, these also a little lower than in other types of are alloy steel toothed impact rings with an automobile shredder. internal diameter which is larger than the Scrap which is too iong is not shredded but axle around which they can freely rotate. receives a few hard knocks and is then These impact rings can therefore leave passed out through the comparatively large space for passing scrap. The further the kick-out door. In this short time, however, scrap drops, the smaller the space between the scrap is knocked clean, and cleared of the ring hammers and the liners or wear concrete, wood, rust and paint, etc. resistant walls becomes. At the top of the rotor housing a number of It would seem that the reversed direction of fixed 'wings' are attached to the rotor shaft, rotation, without the benefit of direct with a smaller diameter than the discs with nibbling or grating, would be at a high cost rings. The raw material is torn apart by to productivity. But that turns out not to be these wings to prepare it for the grinding the case; we have seen a 3000hp Kondirator action of the rings below. which processes more than 250,000 tonnes of scrap per year without any problem. Dedusting takes place at the bottom of the Since the input scrap is not knocked down- mill, while the kick-out door is at the top. 110 1111111 Wendt Corporation Close Dec., Ex. A A secondary dust collection unit is nowa The total weight of either of these mills is days placed on the (zig-zag) air classifica considerably less than that of the horizontal tion unit through which the scrap falls. shredder. The two motors of the 700hp Henschel mills are available in two types: machine give it a stable drive and reduce the load on the bearings.

The Henschel mill has the advantage that the scrap receives an intensive series of knocks on its way from top to bottom and is thus made fairly small, more or less rounded, and fairly clean.

Disadvantages are the fairly low produc tion rate (not much more than some 10- 20,000 tonnes per year), fairly high wear and tear, rather high energy consumption, Fig. V-11-10 Two types of a Henschel mill. Top: The fast wearing of the impact rings, and the smaller 340hp mill, driven by one electric motor. fact that pre-cutting or pre-shredding of Bottom: The 700hp mill, driven by two electric motors input material is necessary. (on either side of the mill). The main shaft is in the vertical plane. At W the hinges to open the mill, at X, Removal of the rotor takes slightly longer the 'ripper-wing', Y the milling rings, Z the manganese than in the case of current horizontal shred steel wearplates. Feed is from the top, discharge at the ders. The younger generation of mills, like bottom; a grate is unnecessary as the three layers of the shredders, can be opened hydraulically, milling rings reduce the size of the scrap efficiently. thanks to the hinges on the side of the ILLUSTRATION BY COURTESY OF HENSCHEL, KASSEL, GERMANY. housing. Another slight disadvantage is that long wire, such as steel, aluminium or copper cables, can quite easily become wrapped around the main rotor and block it.

On the other hand, the Henschel mill has proved very suitable for the re-shredding of scrap - for example, to make extra dense, super clean cooling scrap - and the shred ding of waste incineration scrap and non ferrous metals.

Worldwide this concept has not proved successful for automobile and similar types of scrap.

11-F 'WET' SHREDDERS

In these machines an amount of water is sprayed into the rotor housing (or shred ding chamber) and is then recovered from it. In the 1960s Luria Bros. in Los Angeles used mining equipment including a wet jigging table to achieve separation. The system was obviously ahead of its time.

Nowadays wet shredders are available as fally wet - with a abundance of water streaming through the rotor housing-, semi wet shedders with a reduced stream of water being injected, and damp s]:i.edders

111

Wendt Corporation Close Dec., Ex. A Fig. V-11-11 The Henschel mill in operation. Left: The feeder conveyor, below the rotor housing. Right: Inclined discharge conveyor with a drum-magnet at the top. Top: The dust collection system. PHOTO BY COURTESY OF HENSCHEL.

where a fine mist of water is sprayed into foil of the explosion hatches burst open the the housing. shredder had to be stopped to reattach. these foils. 11-F-1 ADVANTAGES Currently, this is less of a problem as the The great advantage of wet shredders is that explosion hatches are covered with plastic they can often do without dust cyclones, or rubber flaps which are attached only at saving an investment of a few hundred one side, simply flapping open and closing thousand dollars and entailing a corres again when explosions occur. ponding drop in energy consumption. In fact, the energy consumption of the Finally, an advantage of the wet shredder is entire wet shredding installation can be less that the scrap is rinsed clean, although it is than that of the dedusting unit of a 'dry' said that dirt will stick to the scrap again shredder. anyway and the stock of shredder scrap will rust more swiftly. Furthermore, the dreaded dust explosions in the rotor housing are avoided, or at least Manufacturers of wet shredders claim that greatly reduced, thanks to the presence of the loss of metals - non-ferrous in particu water. lar - in the shredder dust is lower. In the past dust explosions caused much Experience does not prove this, however, delay. When the plastic or thin aluminium for many non-ferrous fragments, e.g. from

112

-· Wendt Corporation Close Dec., Ex. A splintered aluminium sumps and pistons, 3 - In cold climates, water from the shred can remain in the wet dust. der may freeze, with all the obvious ensu ing problems. 11-F-2 DISADVANTAGES 4 - Dust is not sucked away, but immediate ly precipitated, making the shredder waste As already indicated above, wet shredding much heavier. With a landfill cost of some has its disadvantages and the number of times over $50 per tonne - a multiple of this these installations is therefore fairly limited. in places such as Japan and Germany Of the more than 800 automobile shredders nobody will want to pay for dumping the in the world, the wet type represents added water! A partial solution to this around 5 to 10 percent, but in North Ameri problem involves compression of the dust, ca they have become more popular. so that the liquid is squeezed out. However, Disadvantages of the fully wet shredder it has been found that 10-20 percent water include: still remains, which with an output of 20-25 1 - A lot of water is used which needs to be percent of shredder dust results in signifi cleaned or recycled. This is often not carried cantly higher dumping costs, and thus out continuously, however, with the water substantial cost increases. becoming dirtier and dirtier throughout A fairly new system, developed by Birotech the day. As a consequence even after the in the USA and called flip-fl.ow, may provide product has been dried, a dust 'veil' re a useful solution for dewatering and mains on it. screening various sizes of material. 2 - Soaking wet ground around the shred 5 - Small non-ferrous particles can easily der can lead to delays and environmental stick to the wet dust, with ensuing metal pollution. loss. In wet shredders a mixed stream of

Fig. V-11-12 A wet shredding plant, system Fuji-Newell. 1. Fuji Car pre-shredder. 2. Feeder conveyor. 3. Shredder with water injection. 4. Two magnetic drums. 5. Water recirculation system. 6. Shredder fluff 7. Non ferrous metals plus an extra bin for separately-recovered cullet. 8. Shredded ferrous scrap under the swivelling stacker. 9. Water 'upstream' system to separate non-ferrous metals and shredder waste/fluff ILLUSTRATION BY COURTESY OF FUJI CAR, OSAKA, JAPAN.

113

Wendt Corporation Close Dec., Ex. A ferrous, non-ferrous and dust leaves the shredder housing. In the normal, dry, shredders there are two separate streams. The separation of the ferrous/non-ferrous stream by the drum magnets can be com plicated by the damp environment. According to one supplier of wet shredders, this dampness actually helps in separation. But there is also a belief that the wet system will loosen less of the non-ferrous metal because dry air systems tend to carry away fine particles; some of the lighter pieces for instance of aluminium, magnesium etc. 6 - Opponents of wet shredding point out that the danger of explosion of LPG tanks remains.

With respect to the problem of freezing, producers of wet installations report that the heat generated in the rotor housing raises the temperature of the water, so that it takes longer to freeze. The amount of water used remains an issue: too little and Fig. V-11-13 An engine-puller mounted on an not all the dust is captured, while too much excavator (or forklift truck). The long forks rest on the water forms a dust paste and causes car's roof to facilitate the pulling action. 'waterfalls' to pour from the shredder. PHOTO BY COURTESY OF AL-JON, OTTUMWA, USA.

In the American Hydrosort system, from D.J. Wendt Corp., the closed concrete floor (Section V-11-6) can also eliminate part of below and around the wet shredder was at the metallics left in the dust. an incline, leading to a central catchment basin. In this system rainwater is also In the USA Martin Marietta Magnesium has collected - and recycled - from the entire introduced a foam injection system which floor around the shredder, providing also suppresses fires and explosions. sufficient water in areas with normal rainfall. 11-G ACCESSORIES AND PERIPHERALS

Efforts have been made to reduce the There is a wealth of upstream and down disadvantages mentioned above by stream equipment available for shredding. the introduction of 'semi-wet' or 'damp' Upstream: shredders. - engine pullers (Fig. 5-11-13) In these less water or a fine water spray is - petrol tank piercers (Fig. VI-5-3) blown into the shredder housing and the - preshredders big puddles of water found around wet - hinged slatted steel delivery conveyors shredders do not arise. The dust collection (Fig. VI-2-6), etc. plant can now often be dispensed with. and downstream (Fig. 5-11-lb): The presence of damp may however lead - drum magnets to problems of dust and/ or non-ferrous - separating and screening drums fragments sticking to the product. - sensors The SOOOhp SHD shredder of Mayer Parry - axle pullers, etc. Recycling at Willesden, London, has a com puterized damp injection system which In Chapter VI, which is concerned particu replaces the former (fully) wet system. larly with accessories for recycling in Thanks to the computer-regulated water general, more are described. stream explosions have become rare. The injection nozzles are placed under the In addition there are various other accesso kick-out door. An eddy current system ries, particularly for recording information.

114

Wendt Corporation Close Dec., Ex. A Fig. V-11-13a Briquetter for shredder waste. Shredder waste, or fluff, has to be disposed of by dumping or incineration. It is voluminous, light and often wet. Briquetting may provide a solution to the problem of what shredder manufacturer Lindemann calls CAR (Conditioned Automotive Residue). CAR can be used as a substitute for pulverized coal as in cement kilns and may serve as a reduction agent in blast furnaces. SKETCH BY COURTESY OF SVEDALA LINDEMANN.

For example: conveyor to the scrap storage - Weighing apparatus for the permanent - the containers for shredder waste, non registration of: ferrous, etc. - input material - output material: It has also proved possible to monitor what - scrap is happening inside the shredder. - non-ferrous At a Kawasaki installation in Japan we saw - shredder dust the operator able to keep a regular check on - Continuous computer-steered recording the upper grid by means of a camera posi equipment for the visual and written tioned at a tiny hole in the rotor housing. recording of consumption of: With scrap flying around at high velocities - energy and the perpetual presence of dust, a very - water (for wet and semi-wet shredders) small hole was essential if the lens was not - Monitoring by means of video cameras to be blocked or even damaged. As the enabling the operator in his control cabin interior of the shredder housing is of course to keep a permanent eye on essential dark, it was necessary to provide a source of equipment, such as: light, such as a laser beam. - the loading chute and/ or feed rolls - the delivery conveyor belt at the rotor Other examples of accessories are: housing exit - nitrogen dampers in the rotor housing to - the drum magnets extinguish fires - the sorters - sprayers to introduce water into wet or - the sorting drum(s) semi-wet shredders - the conveyor belt or ferrous stacking - de-watering apparatus

115

-· Wendt Corporation Close Dec., Ex. A Fig. V-11-13b The briquettes shown in Fig. V-11-13a are produced by this 850hp hydraulically-driven double screw press. The extrusion chamber is of sandwich-type design. The machine produces briquettes of 180mm diameter at a rate of around 5 tonnes an hour. PHOTO BY COURTESY OF SVEDALA LINDEMANN.

Fig. V-11-14 A huge 660hp Fuji Car pre-shredder or 'ripper'. PHOTO TAKEN IN JAPAN.

116

-- Wendt Corporation Close Dec., Ex. A - explosion hatches sought to break these bales apart, when - axle pullers arriving at the shredder site. - hydraulic bearing lifters Thus, as early as the 1960s, rippers or pre - hydraulically-activated 'moving' anvil or shredders were used, mainly for this pur breaker bar pose. - vibration dampers - sensors, eg on the ferrous stacking con- When the automobile bundles became the veyor exception rather than the rule, the ripper - sound insulation walls disappeared from the shredder picture in - a bridge crane installation above the Europe and the US. shredder housing for lifting the rotor and/ or hammers But in more recent years these devices have - hydraulic lifting apparatus to open the started to reappear on the market, particu shredder housing larly in Japan where automobiles are still - rotor caps frequently baled. More than 50 rippers from different makers - mainly Kawasaki, Note that pre-shredders, to_be discussed Fuji Car and Morita - have been installed below, can also be considered as an acces there, in the range from around 225 to sory. 700hp. Also in France - CFF - rippers made Naturally this list is not exhaustive, and a remarkable come-back. many shredder owners have added their In Japan rippers are placed mainly at small own accessories. er shredder installations of under lOOOhp, because these generally cannot take com There are also various installations for plete vehicles. The preference is for rippers further separation of the non-ferrous built specially for taking automobiles apart. fraction - mainly the 'wet' sink-float system In Europe smaller shredders are used to and the 'dry' system such as the 'eddy pre-cutting the automobile wrecks with current' method, image processing or colour a scrap shear and then feeding the slabs of sorting and electrostatics. These are dis scrap into the shredder. cussed extensively in Chapter VIL As far as purchase cost is concerned rippers are slightly more expensive 11-H PRE-SHREDDERS/RIPPERS than comparably powerful shears, but their production capacity is generally higher and 11-H-1 RETURN AFTER 25 YEARS can often keep pace with the appetite of the shredder. Pre-shredders, also known as rippers, work But in Japan rippers which can take com much like the rotary shears described in plete automobiles, also prepare other bulky Chapter V-10, but on a larger scale. consumer products for the heavy shredders They consist of two or three counter such as the voluminous cold and hot drink rotating axles bearing several large toothed vending machines of wich there are a few wheels or discs which tear apart bulky millions installed inside and outside scrap such as complete automobiles at buildings. Also bulky heavier scrap can be a very low speed. The toothed wheels have fed into the ripper. a diameter of around 100cm to over 160cm. The arguments in favour of this extra The largest producers of these machines investment include on the one hand the are Kawasaki and Fuji Car in Japan, and large supply of automobile bundles there, Henschel and C&G, Taurus, in Europe. but also the other advantages which These rippers were especially important in a ripper can offer. When a ripper is placed the early years of the shredder when most before the shredder then this can be old automobiles were still baled or logged, smaller, as can be seen below. in order to facilitate transport. We list the arguments for and against These large, heavy bundles could be pro pre-shredding below. cessed only in the most powerful shredders of around 4000hp. 11-H-2 ADVANTAGES But even then, a bale often weighing 1Yz tonnes or more, caused considerable 1 - A shredder with less power will suffice, problems and therefore a means was for much of the bulk of the raw material -~ 117 Wendt Corporation Close Dec., Ex. A has already been reduced. For example, ten that the peak load rates for electricity a 1250hp shredder and a 400hp pre-shred are often a multiple of the 'normal' rate, der can probably produce as much as and in Japan this is one of the main argu a 2000hp shredder alone. Newell Industries ments in favour of the ripper. calculates that to shred one tonne of nor 5 - The problem of explosions in the rotor mal steel scrap requires about 16-18 Kwh housing will be largely obviated and there of electricity. will be less contamination as most oil and 2 - Since only ripped material enters the other liquids will not enter the shredder. shredder, there will be less wear and tear 6 - Pre-shredding is a safeguard against on the hammers and liner plates. excessively large objects blocking the rotor 3 - The noise level of the shredder will be and causing severe damage. lower. The pre-shredder cannot be jammed be 4 - The shredder unit will use less energy, cause of the automatic reversal of rotation and in particular, there will be fewer power direction described below. surges which occur when a large object 7 - Compressed scrap can once again be enters the shredder. It must not be forgot- supplied. This is particularly important in

Fig. V-11-15 The Fuji Car pre-shredder system. Top left: A bundle is brought into the pre-shredder. Right: It is caught by two huge toothed wheels and ejected. Below: When the bundle is too dense to be ripped apart, the rotation direction is automatically reversed and a hydraulic wing advances to 'flatten' the scrap by pushing it against a roll. Now it can pass between the wheels and be ripped apart. ILLUSTRATION BY COURTESY OF FUJI CAR, JAPAN.

118

Wendt Corporation Close Dec., Ex. A Fig. V-11-16 Kawasaki pre-shredder. This machine is about 4 metres high and has three wheels, each with 10 teeth. ILLUSTRATION BY COURTESY OF KAWASAKI HEAVY INDUSTRIES, JAPAN.

Japan where the narrow streets of towns An extra argument in favour of the pre and cities preclude the transport of com shredder is to guard against sabotage. plete automobiles. It has happened - in Germany - a railway 8 - Savings can be made on the manpower axle was concealed in the transmission which would be necessary for the inspec tunnel of a passenger automobile and tion of the wreck for gasoline and/ or LPG a worn-out shredder hammer - a massive tanks. On the other hand in many cases the piece of alloy steel weighing 50 to 400kg - pre-shredder itself may still require an below the rear seat. operator. The pre-shredder tears the wreck apart and This would block a shredder - although not the liquids run into a collecting tank below a Kondirator! - and since the rotor cannot it (but this also entails the mixing of all be stopped immediately due to its high liquids). However, inspection will still have angular momentum, something must to take place before pre-shredding, if only break. for 'hidden' waste, discarded tyres and such. The rotor can break or run out of its bear 9 - Henschel, which manufactures pre ings; it is so to speak lifted, as has already shredders, on the contrary, adds that the been indicated above. various liquids are less mixed - so less danger of explosion - than if the complete In either case the damage will soon run wreck were to be put in the shredder. into hundreds of thousands of dollars, Henschel also believes that dioxin genera unless the aforementioned Lindemann tion in the main shredder will be reduced. bearing 'lifting' system has been installed.

119

Wendt Corporation Close Dec., Ex. A In a pre-shredder such blockages are not a problem. Its speed is far lower and fur thermore at each blockage it will change its direction of rotation automatically, causing the piece to be expelled.

11-H-3 DISADVANTAGES

The pre-shredder also has various disad vantages. We can list: 1 - Additional capital investment - a pre shredder can easily cost $500,000 to $1 million or more and naturally requires its own electricity supply. Fig. V-11-17 The interior of a Fuji Car pre-shredder. However, we have already mentioned that Note the toothed ripper wheel and the side-press wing. this can be offset by installing a smaller PHOTO TAKEN IN JAPAN. shredder, and in particular considerable savings - see 4 above - are often made on electricity (peak rate) by the elimination of If necessary the main dedusting unit could power surges and easier processing within include a branch to the pre-shredder. the shredder. 5 - It is not entirely certain that the pre The question of maintenance remains, shredder can avoid all explosions. What especially the welding-up of the teeth. will happen, for example, if an LPG tank Henschel states that this needs to be carried hidden under the rear seat comes into the out for only every 12,000 to 15,000 tonnes pre-shredder? of scrap processed. 2 - The capacity of the pre-shredder is This will probably not be too much of generally lower than that of the main a problem since the first wheel of the pre shredder. This disadvantage must be shredder usually rotates very slowly. cushioned by loading additional small 6 - The ripping process will free oil from scrap on to the supply belt between the the sump, gearbox, and other parts of the pre-shredder and the main shredder. vehicle and tend to distribute it over the The capacity disadvantage must not be metal, but also over the absorbent uphol over-estimated. Fuji Car, for example, stery. An explosion risk is therefore possi guarantees production of 40 tonnes per ble. The danger now exists that these oils hour for its 660 hp pre-shredder. will be 'sucked up' by the hygroscopic This works out at an input of around 70,000 covering of seats, floormats, etc. Later, in tonnes per year. Fuji Car claims, however, the main shredder, this could still cause an that the actual capacity lies between 40 and explosion. 70 tonnes per hour, depending on the input material. 11-H-4 CONSIDERATIONS 3 - The length of the generally slatted-steel supply belt will be greater, and this adds In weighing the pros and cons of pre expense. shredders, not only the extra investment The inter:rp.ediate length for loading small must be considered, but also the invest scrap - bicycles and cans, for example - will ment saved on the main shredder because generally be horizontal, after which the belt a smaller unit of lower horsepower can be can rise to feed the shredder. used, with consequent savings in energy But the large SHD shredders, too, have consumption. a horizontal section to their supply belts, Given the wide use of pre-shredders in simply to be able to satisfy the shredder's Japan, and the fairly recent installation of 'hunger'. The 5000hp SHD shredder at a few of them in Europe, there may be Willesden in the UK (fig. V-11-9) is loaded a good future for them. with at least four cranes simultaneously. 4 - It is open to question whether pre Lower electricity consumption by the main shredders may need some sort of dedust shredder and fewer, or even an absence, of ing; in general this does not occur. explosions could become such paramount

120

Wendt Corporation Close Dec., Ex. A environmental arguments, that they will the object is torn apart between two rotors overshadow all the other considerations. with fixed blades turning against each other in the horizontal plane. It is also interesting that in Japan, where land prices are exorbitant and the most The Fuji Car pre-shredder works according efficient use must be made of available to this principle, but is further equipped space, many pre-shredders are set at right with a hydraulic 'pressing wing'. This angles to the main shredder. The pre pushes the scrap against the toothed rotor shredded material then falls either directly wheels. In the event of jamming, the rotors on to the infeed belt of the shredder, or two are reversed and the wing pushes the scrap belts are used between the pre-shredder against them, so that fragments of scrap are and the main shredder at a 90-degree angle ripped off. to one another. The third type of ripper has three toothed 11-H-5 THREE KINDS OF RIPPER rotor wheels which rotate against each other. This system is used by Henschel for There are various types of rippers, but its 'Zerreisser' (Fig. V-11-17b) and in the three main systems can be differentiated. Kawasaki pre-shredder. In the simplest system, a single slowly In both of these the three rotor wheels are turning rotor with large fixed steel teeth hydraulically driven at slow but differing tears the scrap apart - even a complete speeds. automobile - against the side of the rotor housing (Fig. V-11-15). The hydraulic drive works smoothly, absorbs shocks, and is proof against over Another pre-shredder operates like the loading, thanks to a pressure-relief valve rotary shears described in section 10; thus and reversal of direction of rotation.

Fig. V-11-lla The 600hp Taurus pre-shredder has a production capacity of 110/120 cars, or 70/80 tonnes of bales, per hour. The two feed rolls are powered hydraulically by four Riva Calzoni hydraulic drives. PHOTO BY COURTESY OF C & G, COSTRUZIONI MECCANICHE SRL., DAVERIO (VARESE), ITALY AND TAKEN AT A CFF SHREDDER PLANT IN FRANCE.

121

Wendt Corporation Close Dec., Ex. A The diameter of the ripper wheels often varies; the largest wheels we measured had a diameter of 160cm.

Henschel makes four types, ranging from 175 to 1075hp; Kawasaki has pre-shredders from 150 to 660hp.

The smallest Henschel ripper weighs · 33 tonnes, the largest 112 tonnes, including hydraulic drive motor and electrical ancil laries. The dimensions of the pre-shredders should not be under-estimated. The popu lar 660hp Fuji Car pre-shredder is over 8 metres high, 5 metres wide and 10 metres Fig. V-11-17b The power of Henschel Rippers ranges long, see Fig. V-11-14. from 175 to 1075hp. The lower wheel of this 'Zerreisser' The low speed and automatic reversal of runs clockwise; the upper and right-hand wheels counter rotation make the danger of real blockages clockwise. minimal. So these machines are therefore often operated or supervised by the shred The speed of the three wheels varies from der operator - usually via an extra TV 2 to 14rpm. The wheels of the Henschel camera, or by the crane driver responsible Zerreisser have six teeth, those of the for feeding. Kawasaki ripper 10. The third wheel of this Henschel Ripper turns with twice the 11-I CRYOGENIC SHREDDERS speed of the first one. The cryogenic automobile shredder was introduced by George et Cie. in Liege, Fig. V-11-17c The Henschel Ripper of 520hp. Belgium, but has not proved a success. This is a pity because the advantages seemed great.

Bundled automobiles were passed through a bath of liquid nitrogen, or sprayed with liquid nitrogen or carbon dioxide in a tunnel. They were then fed into a small shredder (500hp at George). The brittle nature of the super-cooled material enabled a minimum of force to be exerted in the shredding process.

Fig. V-11-18 Cryogenic grinding process. GRAPH BY COURTESY OF HOEK LOOS/HOLOX NORCROSS, GA, USA .

122 .. Wendt Corporation Close Dec., Ex. A Furthermore, the metal split along the folds Cryogenic shredding has also been used created in the bales so that small flat pieces for old automobile tyres; this is not cheap of scrap of very high density were pro either, but the thermal recycling of these duced - good for electric furnaces! tyres poses a problem because the main Lacquer and paint flew off, but even more raw material, SBR - styrene butadene important was the positive effect of the rubber - is a thermoset, which cannot be differences in cryogenic conductivity. melted back to its original state. Differences in the degree of embrittlement allowed excellent separation of ferrous A new application of 'cold' shredding is the from non-ferrous metal. The more ductile cryogenic grinding of mixtures of various a metal, the less brittle it became when plastics which behave differently in the cooled. Non-ferrous recovery was maxim grinding process and can be separated ised and the ferrous product was particu afterwards by a classification process. larly low in copper contamination and its Air-classification, screening or a flui:dised value was therefore enhanced. bed can be used to concentrate the different qualities of plastics. To be sure, nitrogen use was high - around 600 litres per tonne of scrap. But, reasoned As burning cables becomes more widely Bobby George, in the 1960s, the early days of forbidden, and decontamination of the the then still expanding oxysteel-making smoke produced becomes more expensive, process, large amounts of liquid oxygen cryogenic cable shredding is beginning to gain would need to be produced and so the ground. nitrogen by-product could then be bought A number of companies in Europe, USA cheaply. and Japan, are applying this technique. See also the following Section, 11-J-5. However, this proved to be a miscalcula tion, for the liquid nitrogen could certainly Finally cryogenic shredding is also applied be sold, and furthermore be used to reduce for the separation of old paint and oil cans. the temperature of a new batch of air in the cascade system of producing liquid nitro 11-J CABLE SHREDDERS AND WIRE CHOPPERS gen. Damp scrap. presented particular problems, 11-J-1 VARIOUS TYPES the 'insulating' effect of water making cooling to the centre of the bundle more Electric cables account for the largest part difficult. of the world's copper consumption.

An advantage of cryogenic shredding is They can be found:' that thanks to the liquid nitrogen or carbon - above the ground in high tension and dioxide the risk of explosions in the shred overhead cables der or dust collection system is reduced to - 'on the ground', in homes, in practically all a minimum. electrical equipment, in means of trans The increased value of the metals was port - automobiles and trains insufficient to cover the cost of the high - below the ground in underground cable, nitrogen consumption, despite the fact that which is generally a composition of many the shredder was smaller than would raw materials otherwise be necessary. After several years - underwater, as the submarine cables which of experimenting and the sale of just one are laid on the sea-bed and obviously have cryogenic shredder in the US, the operation a long life expectancy. ceased. A further problem of the cryogenic Some of these cables are not recycled shredder was that the steel components of because bringing them to the surface · the shredder itself - hammers, axles, wear would be prohibitively expensive, plates, grids etc. - also became brittle, and see Section 11-J-5. developed a tendency to fracture. The use of stainless steel instead of mild steel in the If the 'above ground' cable is not insulated, shredder could have been a solution, but as in the case of the high tension type, would have made the machine considera processing is reasonably straightforward. bly more expensive. Cables 'on the ground', as found in daily life 11111111 123 Wendt Corporation Close Dec., Ex. A Fig. V-11-18a The Eldan 'Omnishredder' for cables, electronic scrap, aluminium scrap etc. On the right is the granulator, and on the left the dust collection unit. PHOTO BY COURTESY OF ELDAN, FAABORG, DENMARK/NIDO, THE NETHERLANDS.

at home, in office equipment and in indus greases, paper, plastics, etc. Furthermore, try, are of course always insulated, and can cable burning offered a fairly simple means be fairly easily processed. Shredding is the of melting the lead from old underground best method, as these types are usually too cables and separating it. This method has thin to strip. already been discussed in Chapter IV-2 However, there are real problems in ('Dismantling with fire and frost'). processing 'underground' cable which usually consists of a composite of perhaps In the same period cable stripping became ten completely different and tightly-packed increasingly popular, as discussed in V-9. materials. Its complex design makes the This was an easy method of freeing the underground or underwater cable immune plastic insulation from the copper or alu to the influence of its often inhospitable minium conductor. surroundings. Ingress of moisture must be But burning and stripping were slow. prevented and the cable must be very Burning also had the additional drawback strong since it has to withstand earth that it was extremely unfriendly to the movements, temperature fluctuations, environment owing to the smoke and chemical attack and other threats. dioxins released, see also Chapter V-9. Stripping of thin cable was not only too Here we have another instance of that slow, but failed to provide a sufficiently common problem: the more compact and clean product. complex an item, the more difficult it is to recycle. An additional drawback arose when the cable to be stripped was not uniform in diameter 11-J -2 BURNING, STRIPPING OR SHREDDING - a frequent occurrence with the hundreds of different types of cable available. Until the 1970s, it was customary to burn The distance between cutting discs, blades or the insulating materials such as oils, ploughs had to be reset for each diameter.

124

Wendt Corporation Close Dec., Ex. A 11-J -3 SHREDDING IS FAST, BUT NOT WITHOUT cable. This is because the latter contain PROBLEMS materials which cannot really be shredded, particularly lead, mastic and bitumen, - · Most cables are now chopped or shredded. and which are also difficult to separate This is a more environmentally friendly (Fig. V-9-3). method than burning, and considerably faster than stripping. These cables also contain grease, so all in But cable shredders or cable granulators, as all the output will be greasy and dirty. they are often called, are expensive. Com Furthermore, these flammable contaminants plete installations can easily cost millions can easily cause a fire in the shredder. of dollars, especially if armoured paper I The lead in the cable sheath causes prob lead cables are also to be shredded in them. lems when shredding because this metal is It would be impracticable to describe every so soft - particularly when it has been system, as there are many dozens of them. heated by friction in the shredder. The lead This is in great contrast to automobile does not break but has a tendency to come shredders, which almost all operate on the away in strips, with the danger that the same principles and differ only in details. metal will become wrapped around the rotor. However, there are two basic cable shred The best method of shredding insulated ding systems. The choice is determined by cable is to treat it cryogenically - see also the input material. 11-J-5. But this involves additional costs for the liquid nitrogen which is required in First there are the 'ordinary' cable shred fairly considerable quantities. ders, for processing simple plastic or rub ber insulated cable. There is also the problem of maintaining the very low temperature, for the insulation of Considerably different are the machines the cooling tunnel has repeatedly proved designed to shred armoured paper /lead a major difficulty. Account has also to be

Fig. V-11-18b REDOMA cable granulating system. PHOTO BY COURTESY OF MBH-BRONNEBERG, THE NETHERLANDS.

125

Wendt Corporation Close Dec., Ex. A Fig. V-11-19 This integrated electronics/cable grinding system forms a complete processing plant. ILLUSTRATION BY COURTESY OF SCANDINAVIAN RECYCLING SYSTEMS AB, MALMO, SWEDEN.

taken of the vulnerability of the shredder Separation is by no means always optimal. owing to the low temperature (-190°C) of The British Dry-Flo system of the 1970s the liquid nitrogen (as has been demon solved this problem by adding an iron strated in the previous section). powder medium which, after shredding, Whichever method of shredding is chosen, was removed magnetically. But in the end separation of metal and plastic is hardly this system did not prove fully satisfactory. ever 100 percent. All too often more than It is not unusual to shred the material more 1 percent copper remains in the granulated than once. Or the 'cascade' system can be plastic, and more than 1 percent plastic used, using successive, ever smaller, shred remains in the granulated copper. In either ders in which the cable is first granulated to case this causes problems when melting. a fraction of under 10mm, and in the next, A 'Corona' electrostat as described in for example, to an under 5mm fraction. Chapter VII-6-B may provide a solution. Separation of copper and plastics can be achieved in different ways. 11-J-4 SHREDDING OF PLASTIC-SHEATHED CABLE The mass can be fed through a sink-float installation (copper is around nine times After cable has been cut into short straight heavier than plastics, aluminium almost lengths, it can be fed into the shredder. three times). It can be air-classified, where Cutting can also be carried out in a cutting by the light plastics are blown further than mill or rotary shear (Chapter V-10). the metal, or it can be separated with the Cable shredders sometimes have fixed aid of an air table; see also Chapter VII on teeth, but often rings, similar to those used these separation techniques. in turnings crushers and the Henschel Mill Simple screening may also be an option, (Section V-11-E-3). depending on the type of cable. In all these techniques the lightest fraction, the It is a prerequisite that the cable is not too plastic(s), is removed first. thin because the shredder will then be It is also possible to remove the heavier, unable to detach the plastic from the cop metallic fraction first with the aid of eddy per effectively. current separators, Section VII-6-B, which project copper and aluminium away from There is also the risk that the heat generat other materials. ed in the shredder will cause the plastic to Many of these cable shredders have dust start melting, so some machines have filters, usually of the cloth and/ or envelope a cooling system in the rotor housing. type.

126 .. I Wendt Corporation Close Dec., Ex. A 11-J-5 SHREDDING OF ARMOURED CABLE, increase by around $0.10 to $0.25 per kg, 'WARM' OR 'COLD' see also 11-I.

The problems become far greater when The cable is sprayed with liquid nitrogen in complex, underground cables are to be a tunnel before being introduced into the shredded. There are hundreds of thousands shredder. The bituminous paper will no of tonnes of these underground or under longer burn and even more important is water and they will undoubtedly be the fact that at this low temperature the recovered for many decades to come. bitumen, grease and oil-impregnated paper Underground cables are a combination of, will become hard and brittle so that they among others, copper or aluminium, can be removed fairly easily. galvanized steel, lead, jute, bitumenised If some paper still sticks to the metals, this paper, oils, grease, chalk, bitumen, mastic may be removed by mechanical brushing and, in the more recent types, plastics or by a hot air treatment. (Fig. V-9-3). The various layers of paper are N.B.: In Chapter VII there is a further short impregnated with oils. In the past these discussion on cable processing and in Chapter were usually mineral oils with resin, but V-9 cable stripping is described. since around 1980 they have been synthetic oils. 11-K ALUMINIUM SHREDDERS Jute has mostly been replaced by polypro pylene since around 1985. Aluminium shredders are often 'adapted' automobile shredders, with most of the Initial processing is the same as for non ancillary equipment such as dust armoured cable: sorting and cutting collection, drum magnets, sieves, conveyor - usually by hand - to lengths of 25-50cm. belts, etc. This is often done with pneumatic or hy draulic hand-held or mini-shears, with Apart from size reduction, the major pur alligator shears, usually on wheels, with pose of aluminium shredding is to remove hydraulic guillotine shears or with rotary iron. If one shredding cycle is insufficient, shears. some shredders provide for it to be repeat ed (see Fig. V-11-20). After this - or instead of pre-cutting - the material is sometimes passed through Of course these will not be heavy-duty a cutting mill which shortens it to pieces of shredders, but make no mistake, too small 5 to 10mm. a unit, say under 400hp, could have prob lems. Next, any ferrous material is removed by an overband or drum magnet (Fig. V-11-19), This metal can be very hard and, further and a second reduction stage often takes more, account must be taken of extremely place in a granulator, reducing the particles· strong aluminium alloy (named 'Duralu to only a few millimetres. minium' in Europe), as used in aircraft Sieving or screening often follows, with construction. larger pieces being fed back to the granula Sometimes, particularly when it comes tor. The smaller fraction can now be sepa from supersonic military aircraft, it is rated by means of air classification - see alloyed with titanium or other metals and Chapter VII - or a shaking table. is often stronger than steel.

Copper and lead granules can be split from The wing spar of a jet fighter can be broken each other in an eddy current separator. only by the most powerful shredders, and Not all the stages in this sequence may be the same is true of the suspension of the followed, and sometimes their order may landing gear. So airplane aluminium is be changed. often shredded in standard automobile shredders; the advantage of this is their The most important of other methods is high speed of production and the removal c·ryogenic processing of the short lengths of of iron. i cable. This offers several advantages, but is l very expensive; the shredding costs will Special aluminium shredders employ l I 127 l

Wendt Corporation Close Dec., Ex. A Fig. V-11-20 An aluminium shredder. Note the special return conveyor (right, after the drum screen) to shred the aluminium for a second time if necessary. ILLUSTRATION BY COURTESY OF LINDEMANN.

various grate~ designed for specific prod closed 'capped rotors' make the danger of ucts, which can usually be changed quickly. this much smaller.

Sometimes they also have an extra provi But there are also manufacturers who sion to avoid aluminium overhead wires, specialise in aluminium shredders like usually with a steel core, becoming American Pulverizer Cy. of St. Louis, Mo. wrapped around the rotor. But the current • 128

-· Wendt Corporation Close Dec., Ex. A 11-L RUBBLE CRUSHERS Since the presence of reinforcing steel in the demolition waste is still a possibility, 11-L-1 NOT 'REAL' SHREDDERS however, there are certain minimum criteria for the strength of a rubble crusher. In terms of tonnage, building and demoli tion waste - rubble - comprises virtually the The material produced in these crushers is largest quantity of material processed by generally used as the foundation for roads. the recycling sector in many West Euro A much smaller proportion is used as pean countries. aggregate in concrete, replacing gravel. An example of this is the new building of This is clearly illustrated by the figures in the Dutch Ministry of the Environment in The Netherlands, where all demolition The Hague, completed in 1992, in which waste must - by law - be processed, inclu 2000 tonnes of recycled concrete granulate sive off all old road material. was used, see the picture ori p. 4.

In 1997 over 15 million tonnes of rubble Three main types of rubble are usually was processed by more than 95 crushers/ processed: bricks and other masonry, con shredders, while the eleven automobile crete and asphalt from rebuilt roads. shredders in the country shredded 'only' around half-a-million tonnes of scrap. 11-L-2 CRUSHING IN TWO STAGES

Shredding implies that the material to be The processing of rubble is a series of processed is hit with such force and at such consecutive operations, of which crushing speed that it will simply have to break. forms an integral part. Broadly, these In rubble crushing, however, the great operations consist of separating, screening strengh of steel does not have to be over and crushing (twice), in primary and come, for masonry is far softer. secondary crushers. This is precisely the

Fig. V-11-21 An integrated crushing unit for demolition waste. Note the 12 conveyor belts, of which 10 are covered, leading to screens, dust collectors and magnets, and for stacking the various grades of secondary road construction material. The company recycled 1.2 million tonnes from an old dumpsite with this installation. PHOTO BY COURTESY OF KLEEMANN REINER, BENELUX/GERMANY.

129

Wendt Corporation Close Dec., Ex. A Fig. V-11-22 Seven different types of shredder for demolition waste/rubble. Clockwise: Grinder with double (toothed) rolls. Impact grinder or 'Prall-mill' with fixed hammers/knives. Cone breaker. Toggle/jaw crusher pivoting from the bottom. Hammer shredder with bottom grid discharge and swinging hammers. Hammer shredder with gridless top/bottom discharge. Toggle/knee crusher with top pivot. ILLUSTRATIONS BY COURTESY OF FAM ZERKLEINERUNGSTECHNIK, UNNA, GERMANY.

opposite order to that seen in automobile insulating foam and plastic sheet among shredding. other things, are removed by hand. This can also be done in a water bath or by The order of operations may vary, but other mechanical means, for example by often this sequence is followed: material is air classification as described in section dumped in the crusher's yard and crudely 11-D-2-C, and in Chapter VIL selected into masonry, concrete and road rubble. After the hand-sorting or mechanical The rubble is then transferred to a storage separation, the material comes to the main bunker and via a heavy - often steel - sieving or screening installation, usually conveyor belt it is fed in batches into via a long, inclined conveyor (Fig. V-11-21). a coarse sieve. This segregates the material. The larger Two fractions are produced, often one pieces, usually of 40-200mm, go to the smaller and the other larger than 200mm. secondary crusher, where the rubble is The latter material is put through the reduced, for example, to less than 40mm. primary crusher. Then a second magnetic extraction of iron takes place and a second sieving or screen The smaller fraction is passed over a second ing installation is entered. This separates sieve or screening system, where the so the crushed rubble into fractions according called sieving sand, usually the fraction to size, which are subsequently transported below 5mm, is separated. The remainder is to silos, bunkers or storage areas. combined with the material from the primary crusher and an overband magnet Dust collection is sometimes incorporated, separates the iron. using cloth or other types of filter. Sometimes the material then passes to But these dust filters are far smaller than a slow-moving sorting belt, where a large those in automobile shredders, where they part of the wood, paper, polyurethane dominate the external appearance. 130 Ml'f Wendt Corporation Close Dec., Ex. A Fig. V-11-23a Mobile rubble crushing installation with crushing stage on the right and the screening unit on the left. PHOTO BY COURTESY OF KLEEMANN REINER, GERMANY, BENELUX, FRANCE.

Just as with an automobile shredder the Examples of fractions include 0-4, 4-8, 8-16, entire process can be controlled from 16-32 and 32-40mm or 0-20, 20-40mm and a central console, where the operator can above. Of course this division may vary; it supervise all the systems displayed dia depends greatly on the requirements of the grammatically on a panel. customer and also on the nature of the input material. Asphalt, for example, is Crushing often takes place in two or more usually crushed into fractions that are stages: primary and secondary, which may different from those of concrete or masonry. be analogous to pre-shredders. But pre shredders are the exception in Europe and 11-L-3 FIXED OR MOBILE INSTALLATIONS the US - although not in Japan - while the static rubble crushers with their much The difference in size, complexity and lower power often do have pre-crushers. strength of the input material is also re These are the jaw breakers, of fairly simple flected in the size of the entire processing design, which 'crack' massive pieces of installation. Automobile shredders are concrete, whether reinforced or not, before complete factories which cannot be moved. they enter the, usually, rotary crusher. It should be remembered that the rotor of The forces to be overcome by rubble crush an average automobile shredder must be at ers are thus far smaller than those automo least 2 metres long - or wide as one would bile shredders have to cope with. Further like to say - to be able to draw in and shred more, automobile shredders must succeed the wreck in one go. in separating all sorts of often tightly Rubble crushers, on the other hand, do not bonded materials from each other. There is need such long rotors, and can therefore be no such complexity for building and demo much smaller. There are now many mobile lition waste. versions which are transported on one or Consequently rubble shredder are usually two trailers, or which drive on their own equipped with fixed hardened alloy steel crawler tracks, to demolition or other sites knives, and only incidentally the loose, (Figs. V-11-23a and b). fully swinging hammers (Fig. V-11-22) which are so typical of automobile The number of mobile rubble crushers now shredders. exceeds the number of fixed installations. Wood, insulating material and glass may The difference can also be seen in the size of be found in the rubble, but usually separate the main motor. An automobile shredder from each other. usually has a motor of some 1250 to 2000 After primary and secondary crushing, hp, rising to 7000hp, while rubble crushers removal of iron by magnet and other un usually have motors of less than 250hp, wanted materials such as wood, expanded although these generally work in primary polystyrene and insulation, the material is and secondary stages. But even the com sieved or screened into different fractions. bined power is usually less than 500hp.

131

Wendt Corporation Close Dec., Ex. A Wendt Corporation Close Dec., Ex. A The electricity supply to a crane-mounted magnet is through a cable which is kept taut by a drum attached to the arm of the crane. This drum usually reels the cable by means of a spring (Fig. VI-4-2a). An additional advantage of more modern magnets is that they do not only attract their load and release it, but that they push it off, which makes them work slightly faster. Another development which can be found in the U.S. and Japan especially, is the Fig. VI-4-8 Scrap grapple. PHOTO BY COURTESY OF combination of a hydraulic scrap grab/ ISOMEC, ISORELLA, ITALY. grapple with a magnet in the centre. This enhances scrap retention and - due to the 'push-off' facility - also releases it more easily (Fig. VI-4-4). Drop-ball breaking or tupping (Chapter V-2) is now also carried out with the aid of A special tool popular in Japan is the clamp magnets. The heavy steel ball is lifted by magnet. Attached to the magnet, which is a magnet and at the highest point the fitted to a hydraulic mobile crane, is a current is switched off so that the ball hydraulic clamp which compresses bulky - usually weighing some 500 to 5000 kilo scrap (for instance refrigerators or soft grams - is released. In the past the drop drink vending machines; the latter of which ball was lifted by a 'breaking hook' which there are several millions in use in Japan was opened by a separate rope, thus and are therefore common feed for shred releasing the ball (Fig. V-2-1). ders) against the magnet. One advantage is A magnet, however, can pick up the drop that the magnet does not release the object ball much faster (see Fig. V-2-2). when the crane turns swiftly (Fig. VI-4-5). Electro-magnets are indispensable at Electro-magnets are also found where shredder plants. Here the mixed shredded ferrous-scrap must be segregated from other material passes over or under one or two materials, like domestic waste. large drum magnets and ferrous metal is They are also much in use at waste inciner drawn away from non-ferrous materials ation facilities, where the scrap is extracted and non-metallic residue (Fig. V-11-lb before or after incineration. This is usually at 11). done with an over-belt or over-band magnet. Above the non-ferrous belt there is often They can also be found when iron removal another over-belt magnet to extract tramp takes place before composting or land ferrous materials which may have been filling. missed by the previous magnetic separa~ tion. Fig. VI-4-7 Loader-mounted trammel screen, used to sieve rubble etc. prior to transporting/loading. 4-B-2 GRAPPLES FOR LOADING AND PHOTO BY COURTESY OF VERACHTERT/VERATECH. UNLOADING

The tine grapple or grab is so common that some scrap firms have adopted it as their logo. The first grapples or grab were suspended from a cable. Pulling a separate rope lifted a ring - known as the 'hood' - which opened the grapple; closing took place by settling the grapple on the material to be lifted, so that the hood fell into a clamp thus securing the grapple. Shortly before World War Two 'double wire' cranes were introduced, equipped

161

Wendt Corporation Close Dec., Ex. A with two sets of winches. The first served system is that the crane is not included in to lift the grapple, the second to open and the unloaded weight of the lorry. In coun close it. This method of grapple suspension tries where road tax is paid on the basis of is still often seen (Fig. VI-4-6, no 1). the weight of lorries and their trailers, this can make a difference of hundreds or even In the 1970s the electric grapple became thousands of kilograms. popular. An electric motor was built into the top of the grapple, opening and closing It could be argued that grabs or grapples the tines either mechanically or electro are not specific to the recycling sector. This hydraulically. These units were much is true in a sense, but the sector is by far the faster and could be used with a single wire largest user of these devices and further crane, which was much cheaper than more the design, of the tines in particular a crane with a set of double winches. (see Fig. VI-4-6a), is usually adapted to Nevertheless, an electricity feeder cable was recycling use. Hence a wide variety of of course essential and to keep this taut scrap grabs/ grapples is available. a spring-operated reeling drum was usually Steel scrap grapples usually have between mounted to the crane arm (Fig. VI-4-2a). four and six sharp tines which grasp the scrap like a hand. Most of the more modern mobile cranes are hydraulic, the lifting arm consisting of To handle steel turnings and other fine a number of hinged sections driven by material so-called orange-peel grapples hydraulic cylinders. The grapples attached are used with wide tines that totally can thus be opened and closed hydrauli enclose the material, and can therefore take cally. Grapples are of the tine or orange a slightly greater volume. peel type. Grapples for handling demolition waste or rubble (Fig. VI-4-6, no 4) often have two Many lorries used by recycling companies rectangular tines, with large slits in them. are equipped with smaller hydraulic cranes This allows unwanted fine sand or earth to which usually have telescopic or hinged dribble away. arms fitted with tine grapples or magnets. These cranes are mounted on the lorry Grapples for lifting automobile hulks - or the chassis or on one - or more - of the roll-on big Japanese soft-drink vending machines - off containers. The advantage of the latter often have two or three tines, or are very

Fig. VI-5-1 A specially designed platform for tapping-off automotive liquids. 1 Movable wheelrest. 2 Container for cooling liquids. 3 Container for sump-oil. 4 Container for fuel. 5 Container for batteries. The funnels in the platform are on wheels for easy positioning under the drain-cocks. · PHOTO BY COURTESY OF CRS, CAR RECYCLING SYSTEMS, DONGEN, THE NETHERLANDS. I

162

Wendt Corporation Close Dec., Ex. A broad and rectangular, so that they can lift one or two flattened wrecks at a time.

5 Ancillaries for motor vehicle dismantling

Motor vehicle dismantlers, and also shred der owners, often use special equipment which comes within the grapple category in its widest sense.

A very specific type is the engine puller which is frequently found in the US, Japan and the UK. This device removes - literally 'rips' - the motor and gear box from the chassis in a single action. See Figs. V-11-13 and VI-5-2.

This is of course considerably faster than unbolting and cutting loose these parts. But why should it be desirable to remove the engine and gear box? After all, a shred der of some 1250hp or more will have no trouble chewing-up the engine of a Euro pean or Japanese car. But it will encounter problems with the heavier six- or eight cylinder American car engines.

In the UK and Japan where there is still ,,: a considerable number of smaller automo di bile shredders in operation (around, or !,f ii even under 500hp) the rugged motors with Fig. VI-5-3 Petrol tank piercer. A hydraulic 'injection i,,' their hardened steel components, such as i needle' pierces a hole in the petrol tank and at the same I crankshaft, gears and springs blades, time sucks the liquid off. cannot be processed. PHOTO BY COURTESY OF BMW CARS, GERMANY.

In any event, engines were or are often removed to be dismantled manually for contents, or to be sold to countries in South their aluminium, bronze and stainless steel East Asia.

The hydraulic engine puller can simply be Fig. VI-5-2 Dismantling unit with hydraulic engine mounted on a mobile crane or forklift puller and tilting table. truck. PHOTO BY COURTESY OF SKET, MAGDEBURG, GERMANY. Two tines grasp the engine after the hood or bonnet has been opened, and the two forks of the forklift truck push against the body. The engine is then ripped away from the chassis and main driving axle. Hydraulic tippers are being used increasing ly to place the vehicle on its side, so that the tap-of plugs are easily accessible, i I allowing the various fluids to be drained (see Section V-11-D-2-A and Fig. VI-5-2). They are also used to give ready access to the catalytic converter which will be re [· moved separately because of its platinum/ palladium or rhodium content. t This tapping-off, which is becoming ever- I: I 163 I· i l,' I '

Wendt Corporation Close Dec., Ex. A rI

Fig. VI-5-4 Hydraulic system to separate the tyre from the steel hub. Three cylinders crush the wheel, thus freeing the inner steel hub, which is reduced simultaneously to furnace size. PHOTO BY COURTESY OF AL-JON, OTTUMWA, USA.

more compulsory under environmental removed; usually tyres have to be removed legislation, precedes the delivery of as well. This 'entsorgt'-ing also has the a vehicle hulk to the shredder. advantage that no dust/ gasoline explo In the past the scrap company sometimes sions will occur in the shredder housing. removed these fluids, but usually it was Most shredder plants in the US have not done at all. The remains of petrol/ adopted this practice too. gasoline, oils and anti-freeze would burn or vapourize inside the shredder. Although tippers, which are fairly simple Whether carried out by dismantler or machines, turn the hulk on its side, this shredder operator, tapping-off is a costly does not ideally solve the problem of business, since each car needs to be dealt wholly effective tapping-off. with individually using facilities often found in the servicing bays of garages. This is why special dismantling bridges or Fairly large amounts of fluid are con platforms (see Figs. VI-5-1 and VII-6-A-2) cerned. A study by the Japanese Automo were developed to remove fluids from old bile Association shows that the average automobiles. vehicle to be scrapped still contains 28.5 li tres of liquid! Examples are water with A dismantling platform is an adapted anti-freeze, gasoline, airconditioning-fluids, garage ramp; it has a hydraulic lifting and six or seven different kinds of oil. system or it is fixed; in the latter case the Incidentally, the German authorities re wreck must be positioned by crane, forklift quire motor hulks to be transported truck or front-end loader. Several hoses, 'entsorgt', i.e. with fluids and battery which lead to collection containers or 164 .. Wendt Corporation Close Dec., Ex. A drums, are connected with funnels to the removed with the tyre still on It, .and in this tap-off points on the bottom of the car. state is offered to a scra.p merc:harttor . dismantler. Given the fact that virtually The bridge is also used to remove items every old car has five wheels and that such as bumpers, shock absorbers, gear millions of them are scrapped each year, boxes and brake disks, which may be it was obviously desirable to develop a tool suitable for second-hand sale, or, like the for removing tyres from wheels very catalytic converter, for further processing. quickly. A range of cutters is available especially in Another fairly new device is the tank pier the U.S. These devices pinch tyre and cer, see Fig. VI-5-3. Gasoline/petrol tanks wheel in three places with the aid of special are often hard to empty. They do not claws and subsequently the tyre is easily usually have a tap-off plug, and using freed, see Fig. VI-5-4. suction via the tank cap is hard work, while removing the entire tank is a problem 6 Weighing aids because the securing straps are difficult to loosen. Cutting torches bring an obvious Weighing of incoming and outgoing goods risk of explosion. is of course a standard task and industrial scales and weighbridges can be found in all Making a hole with a hammer, pick or types of industry. similar tool is not sufficiently effective. But weighing is so essential to the recycling The steel is punctured inwards, so that not business that this sector is the largest all fuel is removed. The tank piercer works individual user of weighbridges for lorries. like an injection needle in reverse. Almost every scrapyard and every paper After making a hole in the tank, the hollow stock merchant of any size will have 'needle' is used to draw out the fluid under a weighbridge (Fig. VI-6-3). suction. There will clearly be less spillage than with a hose and funnel. Worldwide, hundreds of millions of tonnes of recycling goods are collected and pro The recycling sector has a similar problem cessed annually, and almost every kilo when cutting open drums in which many offered to the recyler or shipped by him kinds of volatile fluid may have been stored, so bringing risk of explosion. Thus non-sparking tools such as hammers and chisels made of a beryllium copper alloy are Fig. VI-6-1 An integrated weighing system linked to often used. the office computer. Recyclers also use special drum openers After the truck has been weighed and the data which look like giant can openers and incorporated in the computer, the barrier will open. which are operated manually, pneumati ILLUSTRATION BY COURTESY OF PHILIPS ELECTRONICS, cally or hydraulically. EINDHOVEN, THE NETHERLANDS.

Finally, there are tyre cutters which are becoming increasingly common. Tyres are extremely undesirable in shredder plants. They have a negative value, increase the amount of shredder fluff and have a ten dency to be carried along with the steel scrap because the steel reinforcement in the shredded tyres is attracted by the drum magnet. This means that tyre remnants must be hand-sorted from the metallic outfeed.

Because many shredder operators, espe cially in the U.S., Japan and Germany, refuse car hulks with tyres, they must be removed beforehand. The wheel is often

165

Wendt Corporation Close Dec., Ex. A r

Fig. VI-6-2 Integrated system, built into a domestic refuse truck to weigh curbside waste containers. This system facilitates the introduction of a differential Fig. VI-6-4 A conveyor weighing system which is tariff (DifI'ar). SKETCH BY COURTESY OF ZOELLER-KIPPER used especially by shredder operators for continuous GMBH, GERMANY. weighing of ferrous and non-ferrous scrap streams and non-metallic waste. ILLUSTRATION BY COURTESY OF TTP TON-CONTROL, MUNICH, GERMANY. will have been weighed at least once. Many manufacturers of weighing equip ment have therefore adapted their pro instal a surface-mounted weighbridge, ducts for recycling purposes. which can be moved to any level site in the yard. But most scrapyard weighbridges are Common aids include measures for protec fixed, with the weighing equipment, or tion against fraud, committed either by the 'load cells' placed below ground-level in weighbridge operator or the supplier or a pit. buyer, sometimes in collaboration. The manufacturer therefore ensures that the equipment cannot be influenced by Fig. VI-6-5 Portable aluminium lighweight weighing human intervention. plate, which the truck driver can connect to his vehicle battery or an outside power source. PHOTO BY COURTESY Bars may be fitted along the sides of the OF RAVAS, ZALTBOMMEL, THE NETHERLANDS. weighbridge to prevent the lorry from having one or more of its wheels off the weighing surface after emptying. The reason is clear. The empty weight of the supplier's lorry is subtracted from the previously determined full weight. If the lorry is not entirely on the bridge when it is weighed empty, it will appear as if a larger load has been delivered.

Many scrapyard operators now prefer to

Fig. VI-6-3 A semi-mobile weighbridge.

166

Wendt Corporation Close Dec., Ex. A Fig. VI-6-7 The mobile steel mesh textiles container is tilted hydraulically by a foot-pump and empties itself on the sorting table. PHOTO TAKEN BY THE AUTHOR.

this is based on the weight of the truck. In the metals recycling sector especially, specific densities vary considerably and weights are difficult to estimate. For exam ple, aluminium is more than three times less dense than copper and almost three times less dense than steel.

Steel turnings occupy more space than loose pieces of scrap. But for copper and its alloys the situation is often reversed. Fig. VI-6-6 Mobile weighing platforms such as this A drum can hold a greater weight of brass are in common use by the textiles recycling sector. and bronze turnings than of pieces of tubing and wire. Thus in collecting scrap from demolition More and more lorries in the recycling sites or from companies which do not sector are being equipped with the means possess a weighbridge, portable weighing of weighing and registration on board, so . plates can be of great value to the recycler. that both driver and supplier can imme diately see the quantity being loaded. Many scrap processing companies also An additional advantage is that the driver have weighing systems built into forklift can check whether the load comes within trucks and cranes, or in their warehouses, the maximum permitted in the vehicle's so that they are able to maintain a con carriage weight. tinuous check on how much material they have in stock. Sometimes, however, the truck driver will use portable weighing-plates - as shown in • Fig. VI-6-5 - to check the weight of the consignment 'on the spot'.

But it is not only the recycler who uses these portable hand-held lightweight (aluminium or magnesium/ alloy) weigh ing plates.

In Japan and various countries in the E.U., police also use these devices, to check the maximum permitted truck weight or to ensure payment of the correct road tax if

167

-· Wendt Corporation Close Dec., Ex. A . CHAPTER VII . Identification, sorting and l l ; i i separation ;l

Il 1 Increasing complexity demands collected, or even extracted from domestic additional action waste. But subsequent baling for delivery to the paper mill - the usual processing Primary raw materials are almost always technique for paper stock - would be reasonably homogeneous, as has been useless. The paper mill would have too described in Chapter I-1. Because of this many problems treating the mixture of they can be smelted in large quantities. polyethylene (PE) + card + PE + aluminium + PE as they do not separate effectively in With secondary materials the case is com the pulping process. So a distinct sepa pletely different; they are almost always ration technique must be applied to these delivered in an inhomogeneous state. soft drink cartons. Apart from various processing procedures (Chapter V), additional sorting and separa The same applies, for instance, to old tele tion treatment is necessary, prior to or after phones or TV sets. Shredding the total processing. product will not suffice. Some prior dis When, for example, it is desirable to recycle mantling and sorting will have to take place. the appropriate materials from domestic Paper and glass, discards which members waste, mixed paper stock, or a mixture of of the public are disciplined enough to metals, an extensive range of sorting and thrust into the correct bin or igloo at the separation techniques must be applied supermarket, still consist of a mishmash of prior to usual processing, such as cutting or goods which needs to be sorted by quality baling. or colour. All sorts of impurities must be removed before processing and reconsti For example, drinks or milk cartons may be tution can take place.

Fig. VII-1-1 Identification, sorting and separation of discarded textiles requires many skilled hands, aided by conveyor belts and with containers for the sorted material.

168 -~ Wendt Corporation Close Dec., Ex. A An automobile shredder, Chapter V-11, is its descriptive label. ~veh t11en, which fibre a combination of processing techniques: the in the shirt is which? h.,J~.' i' · shredding itself, followed by separation of The greatest enemy of recycling is the the various materials - more than 30 in an increasing complexity of the materials automobile - after the shredding operation. used. Nowadays few consumer items These separation techniques are briefly consist of a single raw material any more. described in Section V-11-D-2, mainly dust A conglomeration of often tightly-bonded extraction, magnetic separation of the materials is almost always concerned. ferrous fraction, hand-picking, screening A ballpoint pen can easily consist of five to and finally further separation of the non ten materials, a watch of 20 to 30 and a car ferrous fraction. of more than 150 materials or modifications thereof, particularly where plastics are Sorting and separation, preceded by identifi concerned. cation, are particularly necessary for the recovery of discarded consumer products. Design for Recycling (DFR) is vital if the Until comparatively recently, all three recycler is not to be totally handicapped by operations had to be completed entirely the amount of identification, sorting and by hand. The metal sorter, for example, separation necessary. Unfortunately this was indispensable for taking apart and concept - and its implementation - has only differentiating between the hundreds, or been around a few years. Car manufac even thousands, of combinations of metals. turers have been using DFR since about Successes have been achieved in replacing 1990, but it will in general take 15 to these manual operations by machines 20 years for the cars that benefit from this and tools, and even automated sorting approach to enter the recycling stream. technologies, but many of these techniques are still being developed. The techniques described in this Chapter For the sorting of old textiles, paper stock, often overlap, but it is possible to make and plastics, the human eye and human a division: hand are still essential. A: Identification: either 'by eye', i.e. by Other than with metals, these last three people, or mechanically. Optical colour materials are difficult - if not impossible - separation of glass is currently in use, as to separate mechanically. well as laser beams, generally called lasers The mechanical processing is already for short, which can identify white, brown a problem because these materials have and green glass and which, with the aid of almost the same specific densities. a so-called 'airvalve', eject each colour in Furthermore, the colour of products made a different direction (see below). from these materials, does not give any In addition, identification analyses can be indication of their quality. Finally, their carried out in laboratories or on site. application in products or the previous use These analyses can be 'dry' or 'wet'. of these products, indicates little or nothing about their composition. See also Section 4 B: Sorting: Also often 'by eye' and by hand - of this Chapter. particularly for paper stock, textiles and plastics (see Fig. VII-1-1 and 2-1, and sketch In contrast, a metal sorter knows from VII-4-1). experience that a washbasin tap is made of nickel-plated brass, and that a motor bat C: Separation: Still also done by hand, but tery will contain (antimonial) lead. increasing use is made of mechanical But what is the sorter to do with a discard- techniques, which may be dry (blowing or . ed coffee cup? It may be made of waxed sucking, screening or sieving, shaking etc.) cardboard or of different types of plastics or wet (floating or sinking, jigging, etc.). (PE or various qualities of PP), or it may be Dismantling to a large extent falls under B a laminate of various plastics. and C, but, as it generally precedes sorting and separation, it is dealt with separately The textile sorter cannot determine by in section 6-A. sight, experience, or touch the exact com position of a simple shirt, unless it still has Smelting, or more accurately in the case of

169

Wendt Corporation Close Dec., Ex. A ...... 11111!111 ......

recycling, remelting, does not fall within the The technical necessity lies in the fact that scope of this book. This final step in the remelters generally produce a single recycling chain represents a quite distinct quality, or a particular alloy. Unknown activity and deserves separate description. substances in the secondary material can It is touched on briefly in 6-D: 'Melt separa not only be dangerous - for example, tion'. magnesium in scrap aluminium - but may Almost all the processing techniques de also debase the product, whether they are scribed in Chapter V - cutting torches, ingots, semi-manufactures, reels of paper, tupping or drop-ball breaking, shearing, to mention a few. pressing and shredding - aim at reduction in The remelter will therefore refuse mixed, volume. Only in shredding is there subse unsorted consignments, or offer such a low quent separation, usually integrated in the price that the recycler is forced to separate. plant. Furthermore, the recycler sorts because he Reduction does not normally entail separa knows that a mixture of valuable and tion; indeed, with baling the opposite is (much) less valuable materials will often true. Once materials are compressed into only yield the lower value. He therefore a bale, separation becomes much more sorts, for example, bronze from a con difficult, and this is why prior dismantling signment of brass, and high-quality white or separation is almost always necessary. 'woodfree' or computer paper from a batch of mixed office paper. 2 Sorting and separation - the essentials The recycler frequently works with specifi Sorting and separation are often necessary . cations - 'Specs' - which have often been not only for technical reasons, but frequent determined by, or in consultation with, the ly also as a route towards increased value. consumer of his product, so that the sorters

Fig. VII-2-1 Identify, sort and upgrade. At rear left, paper stock is being sorted on a conveyor belt. Subsequently the material is conveyed to the hopper of the paper baler (right). Note the reels of binding wire and (spares) alongside the baler. The five 'needles' which perform the wiring operation can be seen immediately in front of the baler's hopper. PHOTO BY COURTESY OF BOLLEGRAAF/VANDYK, THE NETHERLANDS/USA.

170 .... Wendt Corporation Close Dec., Ex. A "'f'. '

know what is asked of them. Separation reserved for copper. The paper stock sorter equipment can be adjusted to produce will immediately spot cardboard, coloured defined fractions. and white paper, computer paper, etc. and Well-organised recycling organisations drop these into separate compartments or such as ISRI in the US, BMF and BSMA in into containers beside or beneath the the UK, EFR (ferrous scrap) and Euro sorting table or belt (Figs. VII-4-1 and 2). metrec (non-ferrous scrap) and CEPI (pa per stock) in the EU have established Specs That these two techniques are applied which are generally accepted by the recy separately - although in close co-ordina cling industry. tion - has to do with the fact that the techni Of course there are cases in which sorting ques for each differ materially. and separation are unnecessary. If, for A human or mechanical 'eye' is often example, the recycler is offered uniform required for identification. For sorting consignments of a single grade of printers' there is an entire range of 'wet' and 'dry' cuttings, or of window blanks from motor sorting/ separation techniques available, manufacturers, such secondary materials which are described in Sections 5 and 6 can go straight into a baler or be processed below. via some other volume-reduction method. 4 Visual identification; colour, weight, 3 Identification and sorting shape and application still reveal too little

As already mentioned in Chapter I and in Throughout the thousands of years that Section 1 of this Chapter, secondary raw recycling has been taking place, identifica materials can undergo the following treat tion has always been essential. Was the ments, although the order may be varied. broken sword made of iron or bronze, and a - identification if it was the latter, was it a high quality b - sorting/separation bronze? c - processing (after reduction in size) d- melting The visual/manual identification and sorting of paper, textiles, glass and plastics, This order is followed in the recycling of like the sorting of metals, can be mastered paper stock, although melting is of course only after years of practice. There are replaced by 'pulping'. hundreds of types of non-ferrous metals, With metals the order is often different. and more than 100 different grades of steel With an old motor vehicle, for example, and cast iron scrap. Added to that there are · size-reduction by flattening often takes a further 30,000 types or variants of alloy place prior to shredding. In addition, steel. a vehicle may be dismantled to leave a hulk. It is not only the mechanical bonds of metal to metal, but particularly the alloys which However, in the shredding process the present identification problems. sequence may be completely different. It starts by sucking away the light fraction The paper stock sector works with some into the dust collector. This is followed by 60 CEPI qualities, the textiles industry with screening I sieving (for the finer heavy dozens of its own specifications. fraction), magnetic extraction (for the According to the German Fraunhofer ferrous fraction) and finally wet or dry Institute there are more than 5 million manual or mechanical separation. types and modifications - in chemical In shredding plastic-insulated cable, copper substance, colour etc. - in plastics. and/ or aluminium are first dislodged from the plastics, after which any other impuri For centuries, and even today, the sorting ties are removed. So the first treatment is c, of non-ferrous metals took place 'by eye' then comes b, and finally d. and their separation 'by hand', without any mechanical aid. Identification and sorting are often linked. Mechanical identification with the aid of The metal sorter may, for example, recog a microscope - for textile fibres in particular nize a piece bf copper in a stream of do - or with spectroscopes, X-ray fluorescence, mestic waste and throw this into the bin atomic absorption, laser beams, etc., is still

171

-· Wendt Corporation Close Dec., Ex. A Fig. VII-4-1 An integrated sorting/processing system for municipal waste which is being separated into eight different fractions, viz. cardboard, ferrous and non-ferrous metals, wood, paper stock, glass, RDF (Refuse Derived Fuel) and plastics. Mechanical processing entails sieving, magnetic extraction of scrap, shredding and baling. This basic separation plant can be extended with an eddy current non-ferrous metals separator, a bottle separator, a cullet classifier, a plastics sorting system etc. SKETCH BY COURTESY OF BOA, ENSCHEDE, THE NETHERLANDS.

a developing field. Most of the techniques but when oxidised through use or weather involved date from the second half of the ing, the colour indications soon fade. twentieth century - at least as far as their special application to recycling is con In theory, the specific gravity, or density (or cerned. specific 'weight') should be a further indi cator. But that is also very relative. Before the 1970s, metal sorters had just two Old carburettors were often made of za main tools to aid identification - a magnet mak (or 'mazac'), a zinc/aluminium alloy. to determine the presence of iron or nickel, Yet it is fairly difficult to differentiate this and a file. A sorter used the corner of the alloy from an aluminium carburettor which file to give a piece of bronze a short sharp 'feels' just as heavy, despite the fact that tap to reveal the colour. By experience he the specific density of aluminium and zinc could identify the type of bronze. This was differs quite significantly. quite an achievement, since there are more Furthermore, an aluminium carburettor than a 100 types of bronze. may contain more metal without this being Another trick of the trade is to file off visible externally. a little bronze; for instance: nickel-, alu minium-, lead-, phosfor- or manganese For artificially-coloured plastics, the surface bronzes. hardly ever offers any clues. Films/sheet can be made from PVC, LDPE, HDPE, PP If the filings are slightly magnetic, they or PVC. Their specific densities do not will be a nickel or manganese alloy of differ noticeably, each - except PVC - being bronze, which is itself basically an alloy of just under l. PVC is a fraction above 1, so copper + tin + zinc. When these filings are that it will sink in water, unless it has a dropped on to a cigarette paper with large surface area, as in the case of film, a magnet beneath it they will 'stand up especially when greasy. straight'. Another way of identifying plastics is to It may be thought that the colour of a metal expose them to a flame. The colour of the indicates its composition. But, unfortunate flame and the odour of the smoke can ly, there are many greyish metals: zinc, provide a reasonable indication. aluminium, stainless steel and (non Burning PVC, for example, produces polished) chromium steel, tin, and lead. a yellow flame, a stuffy chlorine-like smell When new they 'shine' in a different way, and a choking vapour. 172

Wendt Corporation Close Dec., Ex. A 1 !

Textile sorters may also use a flame. that the propellers of large ships are A thread of pure wool, for instance, will usually made of manganese bronze while smoulder, but will not burn. those of small crafts usually of 'ordinary' Different types of paper and textiles do not bronze. vary noticeably in specific density. A recycler who buys brass condenser pipes Here expertise - and, in the case of textiles, from an oil refinery can expect them to be sometimes labels - provides the best visual of 76/22/2 (Cu/Zn/ Al) alloy, and that indication. those from a sugar refinery or from a ship's Will the shape or purpose of a recyclable condensing boiler, see Fig. V-5-2, will product offer any indication? With metals usually be of 70/30 alloy. this is often the case; for textiles by no means always, as indicated above. A shirt Brass types are usually 58/ 42 (Cu/Zn) or may be made of nylon, cotton, polyester or 60/40, but the 70/30 quality will be worth even silk or of any combination of these more because of the higher copper content, materials. since copper is, of course, more valuable than zinc. The latter will therefore be sorted The same is true for plastics. Packaging and stored separately. may be of LOPE, HOPE, PVC. Plastic bot tles may be made of PVC, PET, PP or PC. Although there will be hardly any dif PET bottles often have a collar below the ference in colour, the shape or purpose may screw top, but this is not universal and provide an indication. If this fails, the type recognition will be too time-consuming of metal or alloy must be determined when large quantities are involved; and analytically. almost impossible if they are delivered in bales. If a kitchen pan is not made of cast iron, stainless steel or enamelled steel, it will Yet there are examples of plastic products often be made of 'wrought' aluminium. where the exterior shape does help in A pressure cooker is likely to be made of identification. Window frames and water 'cast' (alloyed) aluminium. pipes will generally be made of PVC. A metal sorter will know that razor blades Thanks to lobbying by recyclers, supported are usually made from chrome steel by the environmentalists or 'green' groups, (13% Cr). The drum of a domestic washing the majority of manufacturers of plastic machine or dryer is usually made of bottles have incorporated a uniform identi chrome (13% or 17% Cr.) or of stainless fication mark on the base of their bottles: steel; here a magnet will provide the an the well-known three curved arrows with swer, for stainless steel is not magnetic, but a cipher or letters in the centre. chrome steel is.

Paper is a case apart. The CEPI list of Cutlery is generally made of chrome steel, specifications is strongly application 18/8 stainless steel or nickel-plated brass; oriented. But cartons can be made of solid the latter may be silver-plated. Antique or corrugated board and perhaps laminated cutlery may have a high silver content. with some kind of plastic or film. Sorting of cutlery may be rewarding be cause nickel is worth more than three times An experienced metal sorter will certainly as much as copper, and more than four look at shape - especially when colour and times as much as brass. weight are not sufficiently exclusive - but also at the Junction, the source, or the Pure silver would, of course, be too soft for application of the piece of metal in question. cutlery, so an alloy is unavoidable. If the sorter is in doubt, because, for exam He will know, as mentioned in VIl-1, that ple, the type of alloy is not engraved on the a bath tap is made of brass, even if it is cutlery, he will first use his magnet (stain silvery in colour, because of the inevitable less or chrome steel) and then his file - chrome plating. because filing will allow him to recognize He will also know that hinges are often the brass which is plated by a chromium made of brass (but of another alloy), layer.

173

Wendt Corporation Close Dec., Ex. A Fig. VII-4-2 The 'Astrid' is a rotary sorting station capable of 5,000 to 20,000 t/year of municipal waste, paper stock etc. The carousel is supplied by a conveyor. The flap in the middle progressively moves the waste closer to the sorters and is used to evacuate items which have been rejected at the end of the operation. PHOTO BY COURTESY OF AKROS, CHAMBER¥, FRANCE.

174

Wendt Corporation Close Dec., Ex. A T Incidentally, descriptions on objects are not necessarily reliable. Many manufacturers of chrome steel cutlery cheerfully describe it as 'stainless', even though it is not 18/8 (Cr/Ni).

5 Mechanical identification - radiation detection

When sorting 'by hand and by eye' fails, and with the complexity of the materials used in consumer items becoming greater, the recycling industry increasingly has to resort to mechanical identification. Of course laboratory analysis is possible, Fig. VII-5-2 An optical emission spectrometer is but this usually 'wet' chemical analysis is a more sophisticated means of on-the-spot analysis of far too slow for the large quantities of alloy steel, and also of non-ferrous metals such as mixed goods which the recycler usually copper and aluminium alloys. This electrically-powered receives. Metalscan/Analoy spectrometer has a memory which There are kits available that provide stores analyses of hundreds of alloys. It reads the a range of acids enabling on-the-spot deter spectral lines of the metal to be tested and compares mination of the type of steel alloy being them with standard analyses in its memory. A read-out dealt with, or of the type of copper appears on a screen or is printed on a paper strip. PHOTO BY COURTESY OF ARUN TECHNOLOGY, USA/UK/NL.

Fig. VII-5-1 The Portalyser - Portable Alloy Ana lyser - is a sort of portable wet laboratory. It facilitates simple, cheap, fast, on-the-spot analysis of nickel, (Fig. VII-5-1). However, this is a crude chrome, molybdenum etc in alloy steel. means of analysis, in which the colour A piece of wadding is impregnated with one of the six change generated by the reaction of acids included in the kit. Following the electro-chemical the metal to the acid is compared with reaction of the metal with the acid(s), the change of a standard table. This method fails, how colour of the wadding can be compared with the ever, if dirt and/ or chromium, nickel, standard colour-reference card in the lid of the test cadmium or zinc are not removed first. unit. PHOTO BY COURTESY OF HESELMANS MATERIALS Another 'portable' means of identification, CONS., ROOSENDAAL, THE NETHERLANDS. based on conductivity, is a mobile electrical analysing tool, which either works on batteries or is connected to the mains supply by a long cable. With this tester reasonably accurate analy ses can be made on the spot, particularly of alloy steels and different types of copper and aluminium. A number of standard alloys are program med into these machines, e.g. 18/10/2 (Cr/Ni/Mo) stainless steel or 76/22/2 condenser tubes.

The analysing tool then compares the metal to be tested with the alloys which have been programmed and stored in a compu ter memory, Fig. VIFS-2.

Analysing tools which work on the basis of spectral analysis are X-ray fluorescence, a non-destructive method, and spark and laser analysis.

175

Wendt Corporation Close Dec., Ex. A Fig. VII-5-3 The portable Metallurgist is a high resolution X-Ray fluorescence spectrometer using a mercuric iodide semiconductor for fast alloy analysis. There are 21 elements and 200 alloys programmes in the Metallurgist XR and the user may add up to 25 custom alloys. No customer calibration is needed. The data processing unit weighs less than 15lbs and is battery operated for 8 hours field work. The hand-hold probe weighs 2.4lbs. The battery may be charged in place or easily removed and replaced by a fresh battery pack. PHOTO BY COURTESY OF TN-SPECTRACE, ROUND ROCK, TX, USA/GORMLEY, ONTARIO, CD/AMERSFOORT, NL.

Fig. VII-5-4 The Radcom wireless barge/ship radiation detection system with remote control console is initially raised by crane. Then a motion sensor detects the movement, power is applied to the detector assembly and communication with the controller is established. The detector is then moved into position above the scrap load and lowered until the detector is 1 to 1.5 meters above the scrap, as indicated by the 'Material Present' indicator on the controller. The scrap load is then scanned by moving the detector above the scrap at a rate up to 1 meter/second, covering a 3 meter wide path with .each pass. The process is repeated for each 1.5-2 meter scrap layer until the barge/ship is completely unloaded. In loading operations the procedure is done in reverse order. PHOTO BY COURTESY OF RADCOM SYSTEMS INC., USA, AT THE NEWCO TRANSHIPMENT YARD IN AMSTERDAM/ROTTERDAM ..

176

- Wendt Corporation Close Dec., Ex. A li With spark and laser analysis a small hole is which works with the aid of a minutely burned into the material to be investigated. focused ray of laser light. Fairly new is The metal vapour in the plasma thus gene image processing or colour sorting as de rated is then analysed in a split-second by scribed hereafter. its spectrum. Any coating should preferably first be filed away or otherwise removed. A recently-adopted means of non-destruc Laser (beam) analysis is a destructive method tive testing which is now found in more

Fig. VII-5-5 Spotting radio-activity. Radiation detection system installed - clockwise from the top - at a weigh bridge, a steelworks, a railroad track, an infeed scrap conveyor belt, and a gantry crane for loading scrap. PHOTO BY COURTESY OF EXPLORANIUM, G.S. LTD, RADIATION DETECTION SYSTEMS, MISSISSAUGA, ONTARIO, CANADA.

177

Wendt Corporation Close Dec., Ex. A ...... ~ ...... ------~~~~~~~~~

and more scrapyards, is radiation detection with a Geiger counter; often these devices are hand-held.

Various incidents with radioactive scrap from Brazil, Mexico and the former USSR (including the Chernobyl disaster) have prompted the installation of radiation detection meters in scrapyards and many steel mills. These meters are usually placed beside or above the weighbridge, or in the melting shop (Fig. VII-5-5).

6 Mechanical processing by sorting/ separation

It will be clear that sorting, which, after Magnetic extraction of tinplate cans. collection and identification, is usually the PHOTOGRAPH BY COURTESY OF ERIEZ MAGNETICS EUROPE, third step in recovery, is in general impos . LTD, NEWPORT, GWENT, U.K. sible without prior or simultaneous identification and quality control. metallurgical processes. The latter can be The two operations are therefore often subdivided in hydro- and pyro-metallurgy. closely linked. Sorting (by hand) and The metallurgical methods (smelting) fall separation will also take place in consecu outside the scope of this book. tive steps. Metals are in general first processed by the Sorting/separation of municipal waste physical separation and subsequently by attracts much public interest but gives

Fig. VII-6-1 A plant for separation of metals, paper, plastics and glass, from domestic waste. PHOTO BY COURTESY OF ESDEX/RECYCLING ZOETERMEER, THE NETHERLANDS.

178 ....• Wendt Corporation Close Dec., Ex. A r I major problems. Such a conglomeration of often very dirty and wet materials is in I volved that effective mechanical sorting is still not widely employed. The quantities and qualities of the products recovered are usually too low for the process to be viable. Manual sorting of municipal waste is too slow to be economic and is generally regarded as extremely unpleasant work. The techniques mentioned below are usually derived from existing raw material processing practices employed for other purposes, and adapted to recycling/ recovery.

In broad terms physical separation meth ods can be divided into: A -Dismantling B -Dry separation C -Wet separation Fig. VII-6-A-2 Overview of the CRS dismantling D -Melting line. Background: the car turning machine. PHOTO BY COURTESY OF CRS. 6-A DISMANTLING

Nowadays consumers durables have des is as old as motor transport itself, as is become so complex that the recycler has no trade in dismantled parts. But vehicle choice but to dismantle them. dismantlers remove only those parts that The dismantling of worn-out motor vehi- can be sold on the second-hand market.

Fig. VII-6-A-1 CRS system for an automobile dismantling installation, a so-called 'dismantling street'. SKETCH BY COURTESY OF CRS, CAR RECYCLING SYSTEMS, EDE/DONGEN, THE NETHERLANDS.

179

Wendt Corporation Close Dec., Ex. A ...... ~...... 1111111 ......

Fig. VII-6-A-3 Manual dismantling of used electronic equipment into some 30 parts and secondary materials. PHOTO BY COURTESY OF SIEMENS NIXDORF INFORMATIONSSYSTEME AG, MCiNCHEN, GERMANY.

Fig. VII-6-A-4 Dismantling refrigerators. The fridge They are furthermore interested principally is positioned so that the compressor is easily accessible. in more recent models, the remainder After being tilted hydraulically, a hole is drilled in the going straight to the shredder operators. compressor after which oil and CFC are removed. This means that those materials which PHOTO BY COURTESY OF NIDO, HOLTEN, THE NETHERLANDS. constitute the 25% waste generated by the

Fig. VII-6-B Vibration screen, for separating rubber from shredded scrap among other materials.

180 ....I Wendt Corporation Close Dec., Ex. A shredder: for instance paint, upholstery, The problem, however, is not so much the plastics, glass and rubber, are generally not tapping off from the compression pump or dismantled. ducts, but the relatively high proportion of The disposal of shredder waste, or 'fluff', CFCs in the insulation of walls and doors. has become a major problem; its possible But even for this, a mechanical solution has use as a fuel is inhibited by the calorific been found. value of the remaining metal content and the mixture of many of the materials 6-B PROCESSING BY DRY SEPARATION present. Government authorities are in creasingly concerned that dismantling of There is a wide range of industrial dry old vehicles should be as complete as separation methods of which the following possible. In The Netherlands, for instance, are the most important: the government has decided to stimulate further automobile dismantling by grant 6-B-l. gravity separation ing the dismantler a 'premium' of some $75 6-B-2. (electro-)magnetic separation per car. Everyone who buys a new car, has 6-B-3. electrostatic separation to pay an equivalent sum to subsidise its 6-B-4. particlefor particle sorting eventual dismantling. 6-B-5. image processing The problem remains: what happens to the parts and materials for which there is no 6-B-1 GRAVITY SEPARATION market? And what about the various fluids that stay behind; incineration may be an Within the gravity separation methods, option. a sub-division is also made: As mentioned in Chapter V the average automobile hulk yields over 25 litres of 1-a. industrial screening liquid, including more than seven different 1-b. centrifuging and cyclones types of oil. 1-c. air classification 1-d. friction separators and shaking tables Increased - sometimes subsidized - collec tion of non-metallics, as in The Nether 6-B-1-a Industrial screening lands, will lead to the development of new tools for vehicle dismantling. Similarly,. Extensive use is made of industrial sizing new techniques and machinery are being of materials which is often essential to developed for the dismantling of other obtain products that meet demands of the consumer goods, such as TV sets, photo market. Examples are the processing of copiers, fax machines, refrigerators, etc. rubble or demolition waste by screening, or the separation of non-ferrous metals generated First special equipment was developed to by automobile shredding operations. enable all automobile fluids to be tapped The types of equipment employed are off. Removal of these fluids is already many and varied. Sieving or screening is mandatory in Germany, see also Figs. VI-5- therefore the separation on the basis of 1, 2 and 3. size, with the aid of gravity, and is essential to processing and separating rubble, In addition, mobile dismantling units were (see also Section V-11-L). After breaking built, and also entire demolition streets or pulverising, the granulate is passed which are becoming larger and larger, with repeatedly over various vibrating sieves or e.g. tap-off points, tipping installations and screens to divide it into the different frac crushers. tions required, in particular for road construction. A particular concern is the presence of Although there are various types of sieve, CFCs in old refrigerators. Various systems the most common are shaking and vibrating have been developed to tap off CFCs and screens, sometimes constructed as multiple oils quickly and in an environmentally deck systems. The screens are usually friendly fashion. The most suitable system made of metal or plastic mesh or of perfo is to drill a hole in the compression pump, rated metal. Bar sieves or sifters - Sichters or in the ducts leading to it, and to tap off in German (see Fig. VII-6-B) -, can be used these substances into sealed containers. to sort blast furnace and BOF slag, among

181

-- Wendt Corporation Close Dec., Ex. A other materials. The bars are parallel with the cyclone and transported by gravity to predetermined spaces between, and form the underflow. The air cleaned from solids a bed with a free area at one end. As the will leave the cyclone through the core and bars vibrate, smaller particles fall through overflow. the spaces, while any over-size material is gradually propelled towards the free area The efficiency of the cyclone depends on from which it falls into a separate storage, the particle size and drops towards the often for recrushing. These devices are also smaller sizes and lower densities in the used to separate rubber from shredder material to be separated. waste. Depending on requirements of legislation, a wet scrubber has to be added for the final 6-B-1-b Centrifuges and cyclones removal of dust. Under special circum stances, air cyclones can be used for the Separation can be carried out with the aid separation of light from heavy materials. of centrifugal force. This method is applied Examples are the separation of wet paper in various recycling sectors, and is among and plastics, metals from woodchips or others used to remove oil from water and metals from plastics. to separate granulates or powders and The efficiency of the process depends certain other substances in chemical pro heavily on the classification or sizing of the cesses from air. materials. The smaller the size range of the feed material, the better the separation In dry separation systems, air has to be result will be. separated from the solid particles either to obtain the final products or to separate 6-B-1-c Air classification dust collected during the separation from air. Cyclones are widely used for the separa Air classification can be used for resource tion of solids from air. (Fig. VII-6-B-1). recovery after shredding and the initial The mixture of air and solids is fed to the classification of feed materials. There are cyclone where the rotation of the air exerts many types of air classifier on the market powerful forces on the solid particles. with different physical configurations, During the trajectory of the air through the which can be divided into four basic cate cyclone the solids are forced to the wall of gories:

Fig. VII-6-B-1 Cyclone to remove solids from air. Fig. VII-6-B-2 Vertical air classifier.

182

Wendt Corporation Close Dec., Ex. A ferent geometrics in the baffles, the zig zags, or the different feeding or extraction devices.

1. Vertical air classifiers ( Fig. VII-6-B-2) are simple devices for the separation of mate rials mixtures with a relatively large diffe rence in density, like plastics and metals. The air velocity in the vertical channel determines the separation density in the classifier for particles with the same dia meter. In practice, particles in a materials mixture will seldom have the same dia meter which means that classification, for example, by screening is always necessary to obtain satisfactory results.

Consider a mixture of plastics, density 3 lg/cm , and aluminium, density 2.7g/cm3, with the same shape. The difference allowed between the largest and smallest particle for a good separation result would be in the order of 1.6. This means that a materials mixture would Fig. VII-6-B-3 Zig-zag air classifier. have to be screened in the ranges, for example, of 5 to 8mm, 8 to 13mm, 13 to 21mm, and 21 to 33mm. A separate vertical air classifier for each 1. vertical fraction would be a costly and unpractical 2. horizontal solution. 3. inclined Thus this type of air classifier can be used 4. rotary for preconcentration of materials mixtures with a large difference in density. Within each category there are of course The zig-zag air classifier falls within the differences in the geometry of each unit, vertical air classifiers category and is depending on the particular manufacturer. widely used in industry (Fig. VII-6-B-3). For example, air classifiers can have dif- The separation efficiency of the zig-zag air

Fig. VII-6-B-4 Horizontal air classifier. 1 = feed conveyor, 2 = optional airlock feeder, 3 = light fraction, 4 = air blower, 5 = heavy fraction, 6 = mixed fraction, 7 = mostly light fraction, Ba = air flow, Sb = nozzle t/J concentrate air stream. c7"~c-,-~~.....,-.....,,,-~--,,-,---,-,

183

Wendt Corporation Close Dec., Ex. A r~! classifier is an improvement on that of the vertical air classifier because segregation takes place on each crossing of the air flow and the material flow. Typical applications are in the separation of plastics and paper stock. The separation of plastics can be improved by heating the feed material, which causes it to shrink, while separation of paper stock can be enhanced by selective wetting of the paper. Zig-zag classifiers are also being applied to the separation of municipal waste. A further use can be seen in automobile shredding where zig-zag air classifiers separate fine waste particles from the metals or from other non-metallics. Finally, zig-zag air classifiers are widely employed for the processing of construc tion and demolition waste fractions, (see also the Figs. in Section V-11).

2. Horizontal air classifiers are often used in combination with vibratory feeders. Examples are the output of an automobile Fig. VII-6-B-5 Inclined air classifier with vibrating shredder or of a crusher used to process screen. construction and demolition waste. Horizontal air classifiers can be optimised by installing a so-called air-knife, a concen Fig. VII-6-B-6 Inclined air classifier with vibrating trated air stream. screen. In the case of the classifier in Fig. VII-6-B-4, a device can be mounted on the blower (key note 4) to concentrate the air flow (right) on the feed material entering the separation chamber. This process is applied, for example, to the separation of construction and demolition waste.

3. The inclined air classifier is frequently used in combination with vibratory feeders or a vibrating screen, ( Fig. VII-6-B-5 and Fig. VII-6-B-6). This combination of screen ing, inclined feeding and air suction, is used in glass recycling for the removal of plastics and paper stock from the cullet stream.

4. Rotary drum air classifiers (Fig. VII-6-B-7) are used for processing municipal waste, electronic scrap and other products where heavy material has to be separated from light. The operation of these air classifiers is simple and will yield a high throughput. However, the separation efficiency is not as high as for the air classifiers mentioned earlier . 184 .. Wendt Corporation Close Dec., Ex. A r

Fig. VII-6-B-7 Rotary drum air classifier. 1 = to dust collector, 2 = dust, 3 = construction, 4 = rotary drum, 5 = light fraction, 6 = twin screw conveyor, 7 = optional gathering conveyor, 8 = heavy fraction discharge, 9 = adjustable infeed conveyor. Fig. VII-6-B-8 The inclined plate conveyor separator - a combination of frictional and inertial separation.

6-B-1-d Friction separators and shaking tables the agricultural industry and have many For materials mixtures with large diffe applications. rences in shape or density, the inertial or The shaking table consists of a porous deck friction separator is a simple device to through which air is blown. The air picks preconcentrate material or to generate up small particles and these are removed end-products ( Fig. VII-6-B-8). An example via a hood above the deck. The deck is is the separation of a mixture of stones, inclined several degrees and vibrates in the copper wire and circuit boards to obtain horizontal plane parallel to the discharge a copper rich fraction plus stones and side. remaining metals. The combination of forces separates the The feed material is the reject fraction lighter particles from the heavier ones. from an eddy current separator (see Fig. VII-6- The heavy particles are collected at the B-18) used to treat the aluminium fraction higher end of the deck and the lighter from a heavy media separation plant for move to the lower end. automotive scrap. Typical feed products are electronic scrap and Shaking tables (Fig. VII-6-B-9) originated in cable granulate.

Fig. VII-6-B-9 Shaking air table, the porous deck is tilted longitudinal and across. FIGURE BY COURTESY OF MR. L. VISSER, NL.

185

Wendt Corporation Close Dec., Ex. A ......

Fig. VII-6-B-9a The 'banana'-shaped SORTING MAT (SORTEERMAT®), to separate bulky pieces from rubble in fractions over and under 40cm. The mat is fed by the conveyor at the left. Light pieces climb with the upward moving mat, heavy pieces fall back. PHOTO BY COURTESY OF THE THOLE GROUP, ENSCHEDE, THE NETHERLANDS.

Fig. VII-6-B-9b Sketch of the Busschers-type sorting unit. 1. The feed. 2. Heavy fraction (after separation) 3. Light fraction. The speed is adjustable, the turning direction of the steel slatted mat can be reversed. SKETCH: BUSSCHERS B. V. HAAKSBERGEN, NL.

186 HANDBOOK OF

Wendt Corporation Close Dec., Ex. A l

An interesting shaking method is the mild steel, it will generate a magnetic field so-called sorting mat (Sorteermat, Thole as indicated by the lines. The particle P, Group) for construction and demolition waste, which has magnetic property, will travel (see Fig. VII-6-B-9a and 9b). towards the magnetic pole. The force on the particle P depends on the difference The rubble is placed on a heavy, "banana"- between the field lines on one side of the shaped, steel plate belt some 600cm long, particle compared to field lines on the 420cm high and 420cm wide, which has other side of the particle, also called the steel ribs in the horizontal plane. gradient of the field. If the field lines were parallel, the particle P would turn like When the inclined section of the hydrauli a compass needle, but not move towards cally-driven belt is set in motion, the small one of the magnetic poles. The higher the fraction, under 400mm, is pulled up by the gradient of the magnetic field, the greater ribs and deposited behind the sorting mat. the force on a magnetic particle. Therefore, The larger rubble fraction is not pulled up high gradient magnetic fields are necessary by the ribs and rolls back to the horizontal to move weak or very weak magnetic section of the belt. After separation has particles. taken place, the action of the belt is re versed. In general, magnetic separators can be divided into two groups: low intensity and Now the large fraction is segregated hori high intensity. In either case, the magnetic zontally by the sorting mat and deposited field can be obtained by permanent mag by the machine on a conveyor which trans nets or an electromagnet. ports the material to a broad sorting belt. The advantage of permanent magnets is 6-B-2 DRY SEPARATION WITH ELECTRO that they do not require energy to produce MAGNETICS the magnetic field, as is the case with electromagnets. However, with electro Here we have to make the following subdi magnets it is possible to generate stronger vision: fields at a greater distance from the surface of the magnet. 2-a. Magnetic separation 2-b. Eddy current separation With modern rare earth magnets based on Nd-Fe-B, ( Neodymium, Iron, and Boron), 6-B-2-a Magnetic separation strong fields can be obtained at low cost per volume of magnetic field. At present, Magnets are the oldest aid to metal 1 kg of machined Nd-Fe-B costs $200-$300 separation after hand sorting. The removal (or $1400-$2100 per litre), although pro of magnetic material with permanent duction. costs are decreasing and magnetic magnets has been known for hundreds of properties improving. The magnetic sepa years (see Section VI-4-B-1). rators based on permanent magnets are The first permanent magnets were found in slowly catching up on the electro-dynamic nature and used in particular in navigation compasses for many centuries. Their specific use as an aid in identifying Fig. VII-6-B-10 Particle in a magnetic field between and separating ferrous and non-ferrous magnet and mild steel. metals was discovered later. It was not until the discovery of electric current or galvanism that electromagnetic fields could be generated. The work of M. Faraday (1791-1867) and J. Maxwell (1831-1879) made it possible to calculate magnetic fields and design magnetic separators.

If a magnet with a shape as shown in Fig. VII-6-B-10 is placed in the proximity of

187

Wendt Corporation Close Dec., Ex. A ------......

separator. A permanent rare earth magnet The Nd-Fe-B permanent magnets on the 1 metre wide with a length of 0.3m and drum are of alternating polarity and are a thickness of 5cm represents about 15 litres 10-50mm thick. The belt operates at or $30,000 worth of magnetic material. a speed of 30cm to 60cm per second in At lOkW /hour per dollar this means that order to reduce the radial forces on the a 40kW electrodynamicmagnet can be particles when the belt passes over the operated for 8000 hours or about 1 year for drum. the separation of magnetic materials. The drum with the magnets operates at Broadly speaking, for materials smaller approximately the same circumferential than 50mm, magnetic separators based on speed as the belt to optimise recovery of permanent magnets can be used. the stainless steel. In practice, about 50 per High intensity magnetic separators are used cent of the stainless steel present in the for the recovery of magnetite and ferro heavy non-ferrous fraction of auto shred silicon from heavy media separation plants der material will be recovered with this before feeding scrap material to an eddy type of magnetic separator. current separation plant to avoid wear of the machines. The high intensity magnetic The design of the magnetic separator is in separator is also used for the removal of principle the same as that of an eddy irony aluminium, a complex material current separator which is described in consisting of aluminium, and magnetic Section 6-B-2-b. The design of this type of parts mechanically connected such as iron magnetic separator, however, is more bolts. In general, the high intensity magne simple because the very thick and thus tic separator is necessary in eddy current heavy magnets will rotate only at about plants to protect the equipment against 60rpm, instead of the 1500 to 4000rpm mechanical damage. typical for eddy current separators. This An exception is the Steinert eddy current means that the forces on the magnets on separator which has eccentric magnetical the drum in a magnetic separator are about drum in the head pully designed to handle 0.6 times the force of gravity, whereas for magnetic materials with little or no prob an eddy current separator the forces on the lems, (see Section 6-B-2-b). The high inten magnets are about 1500 times the force of sity separator is available not only in the gravity. form of head pully magnets but also as cross Although the basic principle is the same, belt magnets. it is very hard to design a separator which In separation of weak magnetic materials, such functions optimally for weak magnetic as stainless steel, a combination of high materials and as well as an eddy current gradient and high intensity magnetic field separator. has to be realised to induce sufficient force in a particle. In Fig. VII-6-B-11 a schematic 6-B-2-b Eddy current separation view is given of a separator for weak magnetic materials. The existence of eddy currents or Foucault currents was discovered by J.B.L. Foucault (1819-1868) by moving a copper disc in Fig. VII-6-B-11 Magnetic separator with permanent a strong magnetic field. His experiment magnets. showed that a force was needed to move a copper disc through a magnetic field, and that a current was induced in the copper disc which resulted in a tempera ture rise in the disc. In general, one can say that when a conducting object is passing across a changing magnetic field, eddy

Conveyor belt currents will arise in the object, generating ¢= a magnetic field that opposes the field applied. The first practical application of eddy current separation was patented by Weak magnetic · T.A. Edison (1847-1931), who wanted to apply this technique to the separation of

188 ....I Wendt Corporation Close Dec., Ex. A the movement of magnets with respect to the particle. Assuming we have a magnet arrangement as in Fig. VII-6-B-12, a north pole on the top face of a magnet followed by a south pole on the top face of a magnet, a north pole, south pole, and so on conti nuing these alternating poles for a long line of magnets, we have a design for an eddy current separator. If all these magnets are Fig. VII-6-B-12 Magnet arrangement with fixed on a belt as in Fig. VII-6-B-13 (a side alternating polarity. view), with a drive to move the system, we have a design for a magnetic train. If we were to place a train with an aluminium gold from beach sands in California. base on rails very close to the magnets, the Although the idea was ingenious, even train would start moving in the direction of with modern technology it is impossible to the moving magnets. In theory the train move particles smaller than 0.1mm with could reach a speed close to that of the the proposed design. Eddy currents can be magnets. The reason for this movement is generated in a conducting particle by that the eddy currents in the aluminium changing electro-dynamic magnetic fields or base oppose the applied magnetic field by moving permanent magnets. from the permanent magnets on the belt. The first industrial eddy current separators, Not only will the train be moved, but it introduced in 1970, were based on electro will also be lifted by the same forces, dynamic magnetic fields, either by single eliminating the friction between the rail coils or linear motor technology. and the train. The development of rare earth magnets A design for a future long distance eddy from 1978 onwards has been so successful current train based on an electro-dynamic that eddy current separators now offered design is given in Fig. VII-6-B-14. by the various manufacturers (see Table Entering a moving field of permanent VII-6-B-2) are all based on permanent - rare magnets, a metal will be accelerated by the earth - magnets. Because of this develop magnetic field and, depending on the ment, only the practical application of eddy strength of the magnets and the conductivi current separators for the recycling indus ty of the particle will even be lifted. In try based on permanent magnets will be extreme cases, a particle will almost be shot described in the following section. away on entering a very fast-moving mag netic field like the design in Fig. VII-6-B-15. To induce a force in a conductive metal The particles pl and p2 in this figure have particle, the magnetic field must change different trajectories because they have either by the movement of a particle or by different rates of acceleration in the mag-

Fig. VII-6-B-13 Theoretical design for a magnetic train. ~~~~~~~~~~~--:--,-~~~--i

189

Wendt Corporation Close Dec., Ex. A Fig. VII-6-B-14 Eddy current train based on electro dynamic forces. PHOTO BY COURTESY OF HENSCHEL/ THYSSEN TRANSRAPID SYSTEM Fig. VII-6-B-15 Rotating magnetic fields in eddy netic field. This variation is caused by the current separators. difference in conductivity of the metals used for the experiment, or more precisely, The graph indicates that if we have an the conductivity divided by the density. aluminium or any other metal particle In Table VII-6-B-1 the ratio of conductivity, much smaller than a north pole, 'and density', is given, and tells us that the acceleration will be almost zero, which the acceleration of an aluminium particle by coincidence is the reason why Edison's with the same dimensions as a copper separator for gold particles smaller than particle will be twice as much in a changing 100 micron failed. magnetic field. It is also clear from By increasing the size of the aluminium Table VII-6-B-1 that glass, plastic and other particle, the acceleration of the particle will non-conductors will not accelerate. Similar also increase until the particle has the same ly, lead and stainless steel will react very diameter as the length of a pole pair. weakly to a changing magnetic field. For larger particles, acceleration will be constant or size independent, a condition which is important for metal separation.

In Fig. VII-6-B-16 the same relation is shown for copper. If particles pl and p2 were brass, half the pole pair and a pole pair width, the acceleration on pl is half p2. It can also be seen that if pl is an alumi nium particle and p2 is a brass particle, the acceleration of the two particles is the same, which tells us that separation is not

Fig. VII-6-B-16 Influence of conductivity and shape on the acceleration.

Table VII-6-B-1 Sensitivity for eddy currents for selected metals and materials.

Conductivity is not the only influence on the acceleration, but also the size of a pole pair, north and south pole, and the size of a particle, ( Fig. VII-6-B-16). On the vertical axis is shown the accelera tion on a particle in arbitrary units, while the size of the poles and of a particle, are shown on the horizontal axis. j 190 HANDBOOK OF j

Wendt Corporation Close Dec., Ex. A l possible if these particles have the same shape. Shape also has an influence on the acceleration of a metal particle, which means that separation of one metal from another metal is determined not only by the size range of the metal particle but also by the shape. Industrial eddy current separators can be 1** divided in two designs, ( Fig. VIl-6-B-15), 1 type 1 and type 2, each with two magnet 1 configurations A and B, which all have 1 their advantages and disadvantages in i_\_-e,:• -c 1 a separation plant. An overview of some e~)XJ$A) __ ___ 1 producers and patent holders is shown in N+~t~s. (UK) 1 Table VII-6-B-2.

The Steinert design has the advantage that weak and strong magnetic materials will travel with the magnetic drum until the point where the distance between the Table VII-6-B-2 Magnet configuration and patent inside drum and the belt increases. holders. Furthermore, material falling on the inside of the belt will not stick to the supporting The swiftly rotating inner magnetic drum drum of the conveyor belt, because the will make the magnetic particles rotate on magnetic field is only partially present the circumference of the supporting drum (Fig. VIl-6-B-15-type 2). where the feeding belt is not present, and the rota ting magnetic particles will drill If magnetic material drops on the inside of holes through the support drum. the belt or is pulled over the side of the If a large magnetic particle succeeds in i I· feeding belt to the supporting drum, drilling through the support drum rotating i it cannot leave the field of the magnetic at a speed of 60rpm it will reach the gap drum. between the magnet surface rotating at

Fig. VII-6-B-17 Eddy Current Separator (ECS) with concentric rotating magnets. Magnet assembly with alternating polarity.

191

Wendt Corporation Close Dec., Ex. A ...... 1111111111

VII-6-B-17): a weak magnetic fraction, a non conducting fraction such as glass, stones and plastic, including some small metal pieces, and the remainder of the weak magnetic stainless steel and a fraction containing the conducting materials or metals. · The position of the splitter plates A and B determines the composition or grade and recovery efficiency of the products obtained. In general, eddy current separators are used in the recycling industry in combina tion with a heavy media separation plant to improve the grade and recovery of the metal products. Aluminium is the first product from a heavy media plant with feed material primarily from automobile shredder operations. This still contains material which responds to the same density range at which the heavy media plant operates. Fig. VII-6-B-18 Detailed processing of the aluminium These materials are stones, glass, copper float fraction, with eddy current separation and friction wire and complex materials, and represent separation. about 10 percent of the aluminium fraction with a size range of 10-65mm. The alumi 3000rpm and the supporting drum of nium fraction can be separated as shown in 2-4mm. The damage caused by the metal Fig. VII-6-B-18. particle and ensuing repair costs will then The material is dried prior to separation by be considerable. a high intensity magnetic separator. In treating non-ferrous car scrap, an eddy Before feeding to the eddy current separa current separator can produce the tors, the material is screened into two following material fractions (as in Fig. fractions, of 8 to 32mm and 32 to 65mm to

Fig. VII-6-B-19 Friction Separator. PHOTO BY COURTESY OF HURON VALLEY STEEL CORP.

192

- Wendt Corporation Close Dec., Ex. A l

Fig. VII-6-B-20/21 Two Eriez eddy current sorting machines (left) preceded by a Mogensen Vibration sorter (right) separate non-ferrous metals from an incineration plant for domestic and industrial refuse in The Netherlands. Nine of the eleven incineration plants in this country separate these metals with e.c. magnets. PHOTO BY COURTESY OF HUISVUILCENTRALE N.H. (ALKMAAR, NL.), FENIX RECYCLING (ALKMAAR), AND DUOS ENGINEERS AND CONTRACTORS, NL.

reduce the size effect that was discussed concentrate which may be sold to the earlier. The aluminium product can subse copper industry. quently be sold to an ingot maker. The heavy non-ferrous fraction from the The reject fraction contains copper, printed heavy media process can also be processed circuit boards and other metals. with an eddy current separation plant to An inertia or friction separator obtain metal concentrates according to their (Fig. VII-6-B-19) can produce a metal properties as shown in Table VIl-6-B-l.

Fig. VII-6-B-22 Processing of sink product with configuration of eddy current separators. Magnetic separation with strong permanent magnets is performed in the first step.

193

Wendt Corporation Close Dec., Ex. A 6-B-3 ELECTROSTATIC SEPARATION

The application of electrostatic separation of metals/plastics or plastic/plastic combina tions is relatively new, but growing fast. The basic principles of the electrostats, however, are known for more than 2500 years. The Greek philosofer Thales of Milesios (625-548 BC) already noticed that rubbing a cat's skin with amber - then called 'electron' - resulted in the rising of the hairs of that skin. Electrostatic separation is based on the principle that materials with different Fig. VII-6-B-23 The Huron Valley process conductivity's 'lose' their charge in accor schematically. The sink-float fractions aluminium and dance with the extent of the receptiviness heavy non-ferrous metals are processed separately with of an electric charge. eddy current separators to produce aluminium, zamak, copper, brass, zinc, stainless steel and copper wires, The recycling industry uses two types: stone and printed circuits. - 'corona' induced electricity where a high voltage is especially applied to charge non conducting or poor conducting particles, In theory, one could produce a copper, zinc, for example for separating metals from brass, lead and stainless steel fraction as in plastics; Fig. VII-6-B-22. It should be realised, how ever, that size and shape factors seriously - 'tribo' induced electricity where the (shred reduce the grade and recovery rate of each ded) particles of various plastics 'collide' metal product. against each other, thus charging each other according to the tribo electric se In United States practice, if the eddy current quence of polymers. separation plant is well designed, a Zamac product can be concentrated. This product has a very favourable constant shape profile Fig. VII-6-B-24 Principle of the high tension or Corona for an eddy current separator and can be separator. 1 = input, 2 = vibration feeder, 3 = ionizing sold directly to the smelter. electrode, 4 = static electrode, 5 = rotating earthed separation drum or roll, 6 = brush, 7 = neutralising At the moment, an eddy current separation electrode, 8 = variable splitter. NC = non-conductive plant can be used only to concentrate product, M = middling mixture of both products, the heavy non-ferrous fraction for image C = conductors. Examples: metal/plastic, glass/metal. processing (as described in Section SKETCH BY COURTESY OF HAMOS, PENZBERG, GERMANY. 6-B-4-b). n A world leader in this process is Huron Valley Steel Corporation, with plants in V Belleville, Michigan, Anniston, Alabama in 1 de USA and one in Europe, in Overpelt, Belgium, with Union Miniere as partner. A simplified diagram of the concentration plant for non-ferrous metals from a heavy media plant is given in Fig. VIl-6-B-23.

Optimisation of existing eddy current separators is possible because the magnetic materials are still improving and the magnetic field can be enhanced with mathematical modelling to increase acceleration of the metal particles.

194 • !UJl.1.1.1.iii.l Wendt Corporation Close Dec., Ex. A T In electrostatic separation, processed par the bottles are sorted by a machine based ticles are charged with electrons, after on x-ray detection to recognise unwanted which they move towards the positive and PVC bottles which passed undetected or negative poles of the separator. There are were not removed by the PVC sorter. various designs of electrostatic separator After granulation, the 5mm flakes still on the market, such as corona separators, contain PVC (0.25%). vertical electrostatic or tribo-electric sepa The high standard of purity of PET de rators and electrostatic dust filters. manded by the recycling market (less than 10 grams of PVC per tonne) can be A corona separator (Fig. VII-6-B-24) sepa achieved only by employing tribo-electric rates conductive particles from the non separation. conducting ones. The particles are charged After charging the particles by friction in with a charging electrode (3), the conduc a rotating trommel or in the pneumatic tors (C) lose their charge to the drum and transportation system, the PET and PVC move to the right-hand bin, whereas the will become charged according the tribo non-conductors (NC) remain charged electric range. As can be seen PET becomes and stick to the drum and fall into the positive and PVC negative, (Table middle or left-hand bin. Corona separators VII-6-B-3) and can be separated. are used in the wire chopping sector to Good separation results can be achieved segregate metals (copper and aluminium) only under very low humidity conditions, from non-metallic polymers in the range which means that drying is usually neces from 0-4mm. sary prior to tribo-electric separation. The tribo-electric separator (Fig. VII-6-B-25) Under these conditions, different kinds of is used in the minerals industry and for plastics can be separated in a vertical the recycling of polymers - PET bottles, electrostatic separator with opposite for example. Prior to granulation, charged electrodes. The tribo-electric

Fig. VII-6-B-26 Tribo-electric separator. PHOTO BY Fig. VII-6-B-25 Electrostatic Separator; 1 = polymer COURTESY OF CARPCO INC., JACKSONVILLE, FLA, USA. mixture, 2 = conditioning, 3 = tribo-electric charging, 4 = separation, 5 = separated fractions.

195

Wendt Corporation Close Dec., Ex. A Fig. VII-6-B-27 Basic principle of metal detection.

6-B-4 PARTICLE FOR PARTICLE SORTING Table VII-6-B-3 Tribo-electric range of polymers from positive to negative. 6-B-4-a Metal detection 6-B-4-b Sensing systems based on light separator can separate only a mixture of two different polymers or remove one After size reduction to obtain the necessary polymer from a mixture of polymers. liberation of metals and non-metallics, An industrial machine can be seen in various mechanical separation processes Fig. VII-6-B-26 can be applied to concentrate metals or other materials. Product specifications can Fig. VII-6-B-28 Metal detector in a production line. be very strict, such as those for plastics and PHOTO BY COURTESY OF S + S, SCHONBERG, GERMANY glass, and the standard of metals separa tion is still below that required for com mercial application. Apart from bulk sorting methods, it is possible to measure physical properties such as transmission, reflectivity, colour, conductivity and fluorescence with the aid of dedicated sensors.

By measuring predetermined properties per particle, a computer can determine whether the particle has the relevant spe cifications, and if this is not the case, eject the particle with a mechanical device or an air valve.

6-B-4-a Metal detection

Ferrous or non-ferrous metals in, for exam ple, glass, wood chips, polymers or refuse derived fuels, can be detected by a com bination of transmitting and receiving coils with a detection limit of 0.2mm. Depending on the design of the separator, this can increase to larger than 2 mm, but

196 HANDBOOK OF

Wendt Corporation Close Dec., Ex. A by a combination of screening and metal detection units, the final product can be metal-free down to less than 1 gram per tonne. The most simple metal detector is a coil around a belt conveyor which is stopped if metal is found to be present. For plastics with an already low metals content, the usual solution is a combination of transmitting and receiving coil and a mechanical valve, electrically or air activated, which ejects the metal particle and some of the plastic with it. The basic metals non metals principle is presented in Fig. VII-6-B-27, and a metal detector in a production line is Fig. VII-6-B-29 Electronic separator for metal shown in Fig. VII-6-B-28. particles from a mixture with glass or polymer or stone etc. Front and side view. Examples: polymer flakes, A metal detection system with a higher wood chips, glass cullet, stone rubble. 1 = detection capacity and less reject per metal particle is coils 2 = blast valves 3 = electronics and computer. shown in Fig. VII-6-B-29. The material is SKETCH BY COURTESY OF S + S, GERMANY. fed by a vibrator to a "ramp" where the feed material slides down and passes over a metal detector. The distance between the receiving coil and The metal detector, (Fig. VII-6-B-29), con air valves which will eject the metal par sists of a transmitting coil, a U-shaped ticle is ±20cm. copper rod, with pairs of receiving coils in The particles on the ramp travel with the middle of a transmitter. The 20mm size a final speed of about 2 m/ s or 2mm per of the receiver coils determines the resolu millisec., which means that a particle of tion or the size of the particle that can be 10mm diameter arrives over the air valves detected by the system. When a metal after 0.1sec. The air valve has to be acti particle passes over the receiving coils, the vated at least twice the diameter of the electronics connected to the coils can particle, to correct for differences in velo calculate the maximum signal and conse city and ensure it will be removed. quently the location of the particle. The size of the metal particles is often so

Fig. VII-6-B-30 Detailed view of metal detection unit. PHOTO BY COURTESY OF s + s, SCHONBERG, GERMANY

197

-· Wendt Corporation Close Dec., Ex. A ...... ------~------......

Fig. VII-6-B-31 Sensing systems based on reflection and transmission.

large that two or three of the receiving coils 6-B-4-b Sensing systems based on light will detect them, and consequently an area 6cm wide and at least 3cm long will be When particles pass under a light source, removed. In this case, processing glass for differences in colour, transmission, inten the removal of metal particles at a capacity sity, fluorescence and other properties can of 10 tonne per metre width per hour, will be observed and measured. Most materials involve the removal of 50 grammes per ton reflect light. and about 3 to 5% of glass. Only a few materials are translucent like In production, this type of machine will glass and some polymers. detect over 99% of all metal particles larger In Fig. VII-6-B-31 different possibilities are than 4mm and, depending on the settings of shown for measuring the reflected light of the electronic delay circuit and blasting time a material or the transmission of light of the air valves, 95% to 98% of the metal through a material. will be removed. By increasing the recovery The light sources used for these measure factor from 20 to 50 for the non-ferrous ments determine not only the spectrum metals the loss of glass will increase too. which is radiated but also the spectrum The electrical signal produced by the which can be reflected or transmitted. receiver coils can also be processed in There are many light sources available: a different way to determine metal from electric bulbs, fluorescent lamp, Xenon lamp, non-metallics. ultraviolet lamp and a variety of gas-filled The difference between stainless steel and lamps with various emitted light spectrums. non-ferrous metals can also be determined Lasers emit one or only a few spectral lines. with a metal detection system. The reflected light can be collected by

Fig. VII-6-B-32 Schematic view of reflected light collected by a camera.

198 .... Wendt Corporation Close Dec., Ex. A Fig. VII-6-B-34 A combination of a metal detector and an opaque separator. Fig. VII-6-B-33 Optical separator for opaque particles PHOTO BY COURTESY Of: S + S, GERMANY. in a mixture with transparent materials. Front and side view. Examples: glass cullet with stone or and receiver. The electrical signal from the ceramics particles, transparent polymer flake with receiver is also processed by a computer, opaque particles. 1 = laser transmitter, 2 = laser and when applicable an electrical pulse receiver, 3 = electronics, 4 = blast valves. passes to one or more air blast valves for the removal of the contaminants. SKETCH BY COURTESY OF S + S, GERMANY. The identification of opaque particles with laser diodes results in a precise measure a detector which may be one diode or ment of the position of this particle, and in a camera. The size of the spot on the mate combination with the latest generation of rial from which the light is collected deter air valves the ejection will take place with mines the resolution of the system. In the a minimum loss of the desired product. case of transmission, (Fig. VII-6-B-31), the As already described for the metal detec laser beam can be, for example, 2mm, tion system, there is a relationship between 4mm, or 8mm, which is also the resolution the concentration factor of the material to of the system. be rejected and the recovery of the speci In Fig. VII-6-B-32, a camera is used to fied end-product. Setting the parameters of collect the light reflected from the particle these machines is dictated by the value of P. The lens L projects the image on a chip, the specific products processed by the and per pixel three small diodes collect the separator. red, green and blue light information. With increased opening time of the air In this case the pixel on the chip is the valves the use of high pressure air will resolution of the system. Changing the increase, which is a significant cost factor in distance to the particle means that the the operation of these machines; a certain number of pixels on the camera chip col amount of compressed air is used for each lecting data per particle will change too, particle. thus changing the resolution or the number This also means that overgrinding of the of measurements of each particle. feed material, or producing more particles In the recycling industry, sensing systems than needed for the liberation of the mate based on transmission have been used rials during grinding, will result in lower successfully since 1992. An optical separa recovery of the end-product, higher main tion system for opaque particles in a feed of tenance cost, more reject to be landfilled translucent materials is shown in Fig. VII-6- and increased use of compressed air. B-33. The feed material can be translucent A combination of metal detector and polymers with opaque particles, glass with opaque separator in a glass recycling plant stone or ceramic particles as contaminant, is shown in Fig. VII-6-B-34. or other materials mixtures. In practice It is possible not only to sort on the basis of similar to that ofthe metal detector, the zero transmission of light through a parti materials are fed by vibrator to the ramp, cle, opaque/non-opaque separation, but (front and side view), where the material also to measure the decrease of light inten slides down and reaches a speed of about sity or transmission damping of one or 2ml s at the point of the laser transmitter more spectral lines, like red, blue and

199

Wendt Corporation Close Dec., Ex. A Fig. VII-6-B-36 Colour sorting machine with advanced laser scanning system. PHOTO BY COURTESY OF S + S, GERMANY.

detection slot are the receivers with optical filters and electronics connected to a central computer which operates the air valves. The scanning width of this machine is 90cm or 180cm with a capacity for glass of 15 tonne per hour. For other materials, of Fig. VII-6-B-35 Colour sorting based on a sensing course, the capacity depends on the density of the feed material and to a certain extent array. SKETCH BY COURTESY OF s + s, GERMANY. on size distribution. The highly-developed green, or parts of the spectrum, such as scanning system of this type of separator is ultraviolet or infrared. shown in Fig. VII-6-B-36. The generic name of processes based on these principles is: colour sorting. A colour sorting system for transmission For glass, polymers and minerals, machines based on camera technology, designed by are based on sensing arrays with a scan Mogensen, is shown in Fig. VII-6-B-32. ning width of 50cm to 200cm. Machines are The transmission damping is measured by also available based on camera technology a camera and the signal from the camera is for the same width, in which case the processed by a computer which operates material to be scanned is projected by the air valves. a lens onto a chip. This type of camera is described in more A colour sorting machine based on a sensing detail under Image processing (Section array designed by S + S, Schonberg, Germa 6-B-5). At present used mainly for glass, ny, is shown in Fig. VII-6-B-35. The spectral polymers and minerals processing, this lines in which the transmission of light is machine has a capacity of about 10 tonne measured are produced by three lasers - in per hour per metre width for glass. this case red, blue and green - the light from The Mogensen colour sorter has been in which is combined by a prism in the middle. production since 1996 and is applied main The combined light bundle, which we see ly in the minerals, glass and polymer as white light, is reflected on a rotating recycling sectors. mirror which projects it onto optical fibres. As has been discussed earlier, most mate The rotation of the mirror ensures that the rials do not transmit the light but reflect it. light enters each optical fibre one after the Examples of the principles are shown in other. The light passes through each optical Fig. VII-6-B-31. Reflected light can be fibre and leaves it at the scanning of detec collected by an array of diodes with the tion slot where the mater.ial passes same width as the feeding system of the through. material to be separated, or with a camera For practical application, the optical fibres similar to that described earlier. can have a width of 2mm or 500 fibres per Fig. VII-6-B-37 shows a system for reflec metre. tion measurements of materials based on The resolution of this sorter will also be in laser light, a rotating mirror and a detec the order of 2mm. On the other side of the tion system. The operation of these systems j 200 .,,, I Wendt Corporation Close Dec., Ex. A T ! Light transmitted to a material surface is partially reflected and absorbed, and transformed into energy. If the intensity of light, for example of a laser beam, is high enough, the metal will melt or even evapo rate. The metal vapour generated will emit light in which all the spectral lines of the elements in the material will be present. This means that if aluminium has evapo rated under influence of laser beam radia tion, the light spectrum contains all the spectral lines of aluminium. In the case of an aluminium alloy, not only aluminium lines will be present but also those of the alloying elements like Si, Zn, Cu, Mg. If we could measure the whole spectrum of emitted light in a material vapour, we Fig. VII-6-B-37 Reflection measurement based on could theoretically calculate the composi tion of the material. This approach is well laser light. SKETCH BY COURTESY OF s + S, GERMANY. known for analysis of certain materials.

is analogous to those described earlier. Analytical equipment based on either All the systems described so far are all absorption or emission of light is on the based on a line scan with individual market. For the sorting of metals, an ele- processing of each detector.

Fig. VII-6-B-38 Separation system based on LIBS (Laser Inductor Breakdown Spectral analysis).

spectral filter

trigger detector

201

-· Wendt Corporation Close Dec., Ex. A gant solution would be to vaporise from vates the pulsed laser. The pulsed laser each particle one or more spots, analyse the beam is directed on to the scrap particle by spectrum, and eject the different metals means of mirrors and a focusing lens. according to their composition into bins. The spectral lines required for identifica The principle of LIBS (Laser Inductor Break tion are isolated from the plasma generated down Spectral Analysis), see Fig. VII-6-B-38, by the laser beam by spectral detectors has been known since 1967, but industrial with spectral filters mounted in front of applications were not developed until 1987. them, and converted by the detector elec So far, only one system has been tested on tronics for computer evaluation. a large pilot scale by Metallgesellschaft, During measurement, the detector elec Frankfurt, Germany. tronics system ensures that the spectral The system has been designed for the detector registers the plasma radiation only heavy non-ferrous fraction of heavy media during a defined period. This ensures that separation plants for particles between the background noise of the radiation from 15mm and 65mm. the plasma is reduced to a minimum, thus making it possible to identify the various The principle of the sorting machine is spectra more efficiently. shown in Fig. VII-6-B-38 and consists essentially of three components: a singling In the sorting mechanism, the scrap parti mechanism to put one particle after another, cles identified are then discharged from the a detector and a sorting machine. conveyor belt into the corresponding In the singling mechanism, the scrap parti sorting channels by means of pushers. cles are fed in a mass flow from a hopper The pushers, running parallel to and at the via a vibrating feeder to a conveyor belt. same speed as the conveyor belt, are acti The latter has a chicane system to improve vated on the induction principle by the the singling of the metal particles. On the sorting signal. second and third parallel conveyor belts, the particles are accelerated to 2.Sm/ s and 6-B-5 IMAGE PROCESSING transferred to a sorting belt with vertical running guide belt which is under a small Using a camera as a detector in combination angle with the travelling particle on the with a computer, a product on a belt con conveyor belts. veyor is scanned picture-for-picture, or frame-for-frame. Assuming a belt conveyor At this point the particles are in single file 1 metre wide and running at a speed of with some distance between each. 1 metre per second, the images taken with The non-ferrous scrap is now prepared to a standard 3:4 black and white or colour pass through the detector, the centrepiece camera will be 1 metre wide and 0.75 metre of the system. Sensors determine the electri cal conductivity and electronics calculate Fig. VII-6-B-39 Principle of Image Processing used whether each individual scrap particle is by Huron Valley Steel Corporation. metal or non-metallic.

Only the metal particles are analytically identified using the classic atomic emission spectroscopy process. A pulsed laser is used for stimulating atomic emission by evapo rating an area at approximately 1 x 2mm of the scrap to plasma, from which the analy tical information is then obtained. In order to avoid misidentification resulting from surface dirt, etc., the analysis surface of each piece of scrap is first cleaned by means of a shot from a second laser head.

The arrival of individual scrap particles in the detection zone of the conveyor belt is registered by a trigger system which acti- 202 1111111 Wendt Corporation Close Dec., Ex. A T ' The system, used by Huron Valley Steel Corporation ( Fig. VII-6-B-39), is based on image processing. Except for the excellent quality of products sold, no specific infor mation about the technology or the equip ment used in the process is available. The material concentrated by the eddy current separator is fed to the image processing plant. An image processing unit is shown in Fig. VII-6-B-40, the camera being situated on top of the illumination box. Image processing equipment is also used for sorting fish, vegetables, or counting cells in human tissue, as well as many other applications.

Processing frame-for-frame and all lines of the frame at the same time, is one approach to image processing. Another option is to transfer line-for-line from a line scan came ra into a computer and generate a conti nuous, moving, real time line-after-line image of material on a conveyor belt. A standard TV camera records an image every 1/25 second and this is projected on the screen. Because of the human eye's limited speed of processing, we experience the row of stationary images as movement. Fig. VII-6-B-40 Image processing unit at Huron In image processing, either one frame is Valley Steel Corp. processed after the other, or we use, for example, 500 lines each with a width of 2mm. This means that for a conveyor belt long, each 0.75 sec. One frame will have to 1 metre wide, we will have an image of be seized and processed by a computer. 1 metre to 1 metre in the computer to The position of each item on the belt run process with special software ning at a constant speed can be defined by (Fig. VII-6-B-41). a combination of an impulse counter on the side of the belt and the synchronisation of The width of the line or resolution depends the camera with the computer. on the sensor and camera used for the After processing each image, the computer detection of the signal. will activate the air valves of the ejection An example of a system consisting of system for the removal of identified parti a camera, computer and a illumination cles, which, for example, can be brass system is the Mikrosort from Mogensen in particles in a copper product. Hamburg, Germany.

Fig. VII-6-B-41 Two different principles for processing images from a conveyor belt.

203

-- Wendt Corporation Close Dec., Ex. A --

Fig. VII-6-B-42 Principle of the measurement with a line scan camera. SYSTEM: MOGENSEN, GERMANY.

The basic principle of the Mikrosort is 1 Separation, using rising currents and hydro shown in Fig. VII-6-B-42. cyc;lones 2 Sink-float methods The system has been designed so that 3 Jigging transmission and reflection of light can be 4 Flotation measured. The intensities of three colours - red, green and blue - are measured in the 6-C-1 RISING CURRENT AND HYDRO-CYCLONE camera. These signals are processed in real METHODS ~ime against the standard of a dedicated colour model. Because of the dynamic In rising current· a continuous rising column range of each colour signal and the colour of water is projected through a pipe. The model used, data processing can be carried feed material to be separated is introduced out only with the latest computer technolo in the rising column of water. The material gy. which sinks faster than the water GOlumn The system works with 16 million colours rises, falls to the bottom of the separator. . and has a resolution of 0.5mm by a width The material transported by the column of of 1000mm and scans with a speed of 5000 water is then separated from the water by lines per second. This means for a particle a screen or a sieve. The water can be re with a diameter of 3mm that five lines can used in the process (Fig. VII-6-C-1). be scanned with 45 points of colour infor mation. The image 0£ each particle can be In hydro-cycione separation (Fig. VII-6-C-2) processed and data added or subtracted to water, or a heavy media suspension some correct side effects, for example, in the times called ·'heavy water', is brought into glass recycling sector. rotation in a piece of equipment which is a combination of a cylindrical and a conical 6-C PROCESSING BY WET SEPARATION part. As a result of the rotation, larger and heavier particles first move to the wall and 'Wet' separation processes can be subdi then sink along the wall to the underflow vided into: or an apex in the bottom. 204 .... Wendt Corporation Close Dec., Ex. A r

,.o .... ~~ screen • ...... t:::::l ... ~

Fig. VII-6-C-1 Rising current separator.

Lighter, or smaller, materials will remain 2-a: sink/ float in water or another liquid suspended and leave the cyclone via .the 2-b: sink/ float in a suspension of water and a overflow of vortex at the top of the cyclone. solid material. This method is still widely used to clean coal and has also been adapted for separa The method 2-a (sink/ float in water only) ting metals. can be foµnd in the separation of plastics, making use of the fact that, inter alia, 6-C-2 SINK-FLOAT METHOD PVC has a specific weight > 1; PE, PUR, PP and PS usually being <1 (depending on Sink-float methods can be subdivided into whether or not they are foamed). two systems: It is also used to clean the granulate pro Fig. VII-6-C-2 Hydro-cyclone. duced from construction and demolition

Fig. VII-6-C-3 Heavy medium separator.

205 1111111//1 Wendt Corporation Close Dec., Ex. A Fig. VII-6-C-4 Oscillating blade Coarse Coal Separator (OCC-Vessel). SOURCE: WILMOT ENGINEERING COMPANY, USA.

waste. Wood, insulation (paper, PUR foam, As a result the viscosity and the density of board etc.) and other undesirable materials, the suspension changes. which are lighter than water, are thus 'floated out' in a bath of water.

Method 2-b is used particularly for the Fig. VII-6-C-5 A jig; the plunger brings the liquid separation of shredder aluminium and under pressure and speeds up the separation process. magnesium from a non-ferrous mix. The feed material to be separated will be divided into three fractions, light, medium and heavy. Heavy Sufficient ferro-silicon or magnetite is added particles will pass quickly through the screen and be to a water bath, which is kept constantly discharged at the bottom of the apparatus. agitated, to bring the specific density to anywhere between 1 and 3.3.

This enables aluminium with a specific density of 2.7 and magnesium with a density of 1.74 to float (Figs. VII-6-C-3 and 4).

Although sink-float methods are used throughout the world to separate the non ferrous metal output of shredders from the ferrous output, they are not without pro blems. First the suspension of magnetite or ferro silicon in the water tends to be polluted by oil and very fine dirt from the surface of ' the infeed. 206 J Wendt Corporation Close Dec., Ex. A This problem can be mastered with a recovery system for the expensive mag netite or ferro-silicon, in combination with hydro-cyclones. The remaining sludges which are contami nated with fine particles of metals now adays present environmental problems and costs, and must be discarded or cleaned.

Also, various complex materials behave like Al or Mg in the bath. A common problem is plastic-insulated copper wire. The low specific density of the plastic combined with the thickness of the copper core, means that the wire will have an average density of less than 3 and that it will therefore float with the aluminium fraction, which, of course, is not the aim of this separation process. This problem can be solved by adding an eddy current separator to clean the aluminium.

6-C-3 JIGGING

Jigging is one of the oldest methods of gravity concentration. The jig is generally used to concentrate relatively coarse mate rials down to 3mm. When the feed is fairly close sized it is not difficult to achieve a good separation at low cost. In the jig the separation of mate rials of different specific density is accom Fig. VII-6-C-6 Wet separation: The principle of plished in a bed which is rendered fluid by jigging. When a liquid, containing metals etc is put a pulsating current of water. under pressure, the heavy fraction will sink first. On the pulsation stroke the bed is lifted as a mass; then, as the velocity of the water stream decreases, the particles fall with different speeds to the bottom, depending paper industry for de-inking cleaning on their density (Fig. VII-6-C-5). contaminated soil and in some cases to When this process is repeated stratification separate various plastics. of the different materials will take place in In flotation the crushed material, is sus relation to their density, and they can be pended in water. recovered accordingly (Fig. VII-6-C-6). Air bubbles are introduced into the suspen This method is very similar to the rising sion from the bottom of the flotation cell current separation process, but here the jet and will selectively adhere to the particles to of water is projected through the screen in be recovered. pulses. Because of the air bubbles adhering to Jigging is used to separate shredded metals a particle, the density of the material be and particularly to separate plastics from comes less than 1 so that flotation occurs. metals. The foam with the material to be recovered can be collected at the top of the flotation 6-C-4 FLOTATION METHODS cell. Flotation can only be used in the range of Flotation methods originate from mineral 10-500 microns in mineral applications and processing, and are used mainly in the from 5 to 10mm in the flotation of plastics.

207

Wendt Corporation Close Dec., Ex. A After this twin melting process, the remaining metals will have an average copper content of 50 to 60 percent, and can be sold to copper smelters. All the gases generated during these melting stages have to be cleaned by an appropriate system.

The irony aluminium, a product recovered in the processing of automobile shredder residues, is melted in Coreco furnaces to separate the molten aluminium from iron and stainless steel parts.

For melting aluminium turnings, foils and shredded aluminium cans, the melting bath must be covered with salts to preclude oxidation. Fig. VII-6-D-1 Selective melting with a Weiss furnace for shredder fines to recover lead and zinc. These salts are processed in turn, otherwise they are regarded as hazardous waste.

Another method for metal recovery is the 6-D MELT SEPARATION distillation of (zinc) metal, which leads to a very efficient separation. Selective melting with a Weiss furnace But this technique is expensive, particularly Fig. VII-6-D-1 is in use for shredderfines in because of the considerable investment in the size range of approximately 4 to 12mm. distillation columns.

The fines are preconcentrated by jigging Finally there is the very complex metal from an average metal content of 15 to lurgical processing of metals, a process that 20 percent to a heavy non-ferrous concen falls outside the scope of this book. trate of about 99 percent. Recycling - completing the full circle of mate The heavy non-ferrous metals concentrated rial flows - is continuously on the move. by jigging are dried and pre-heated in Recycled materials are now used to make a rotary furnace to maximise the effective consumer products and capital objects, and ness of the subsequent melting process. even to make the tools to recycle these goods again! After feeding to the first furnace the mix ture is then passed by a screw conveyor The recycling techniques themselves are there- through a bath of molten lead which has fore constantly under development. • a temperature of approximately 350°C. And finally: Recycling, good for our environment! Those metals with a melting point of 350°C or lower combine with the molten lead which is kept at a constant level by means of a siphon, or can be tapped-off at regular intervals.

The metals that have not been melted are transferred to a second furnace containing molten zinc at a temperature of 450°C.

The zinc content becomes molten as the mixture passes through the furnace, and can be tapped-off and cast into ingots.

208

Wendt Corporation Close Dec., Ex. A ·'-'411

Recycling, learning by doing ....

... a 'Matchbox' car flattener being· operated by a future Recycler.

209

Wendt Corporation Close Dec., Ex. A About the authors: Alfred A. Nijkerk Alfred Arnold Nijkerk (1930) read law at Leiden University, where he graduated in 1954. After his studies and military service he entered the family scrap business in 1956; later he became general manager of the leading Dutch shipbreaking company. In 1971 he was invited by Royal Dutch Shell to set up a recycling group for Billiton International Metals, at that time a 100% Shell Oil subsidiary company. After leaving Billiton in 1982 he started several companies of his own: a metal-trading company, a consultancy and a firm for editing the two monthly Magazine Recycling Benelux (MRB), a magazine he had started in 1966 on behalf of the Dutch Recycling Federation (FHG), an umbrella comprising 10 member organisations in the field of recycling. He was the editor-in-chief of MRB for 25 years until 1991, and is still active as an editor and adviser. Between 1987 and 1993 Mr Nijkerk was first vice-president and then president of the Dutch Recycling Federation. He was also president of the Dutch Scrap Federation, one of FHG's member organisations, for 25 years. . In addition he was a vice-president of the Ferrous Division and of the Shredder Operators Committee of the international recycling organisation BIR, which has membe.rs in 53 countries. He has written various books on recycling technology and lectures frequently on recycling and 'design for recycling', at various universities in The Netherlands and elsewhere. In 1991 Fred Nijkerk was made a Knight of the Order of Orange-Nassau by Queen Beatrix of the Netherlands. Wijnand L. Dalmijn Professor W.L. Dalmijn (1941) studied at the Technical University of Delft (TUD), The Netherlands (NL), where he graduated in mineral processing. He specialized in this field from 1968-1973 and was appointed professor at TUD in 1991. He has gained considerable practical experience, working at the Sekenke gold project in Tanzania from 1975-1977 and, in the following three years, at a municipal waste recycling plant in The Netherlands where he evaluated and developed recycling opportunities for metals and other materials.

He subsequently advised Metallgesellschaft and Eumet in Frankfurt, Germany, where he developed various technical facilities for scrap metals identification and separation. He also advised Huron Valley Steel Inc. of Belleville, Ohio, Newell Industries Inc. of San Antonio, Texas, U.S. Zinc Corporation Inc. Houston, Texas, and Alcan International of Banbury, UK. He is a member of the advisory board of the principal glass recycler in The Netherlands, Maltha BV, and of the second largest Dutch demolition waste processor, Theo Pouw.

Professor Dalmijn has gained an international reputation for-his work in developing systems for mechanical separation of metals and glass,· including eddy current, laser, image processing/colour sorting and electrostatic techniques. These activities have resulted in a variety ~f commitments to the industries involved.

Professor Dalmijn has been instrumental in revising and extending chapter VII of this Handbook - "Identification, Sorting and Separation". •

Wendt Corporation Close Dec., Ex. A