12 AluReport 02.2012 Recycling Recycling AluReport 02.2012 13
Aluminium recycling on the highest Gear boxes Pressed aluminium chips Lithographic plates Shaft furnace technical level
̽ Ǣ ƥ Ǥ Dross Aluminium cans Window profiles Hearth furnace ǦǦ Ǥ Illustration 1: Aluminium scrap – A valuable material delivered in various forms, recycled by AMAG in various melting furnaces for optimum material yield in an environmentally friendly manner
ts knowledge of recycling, developed 1) Professional checking of incoming raw stead, the recycled material has the same It is mostly objects of everyday use - often After use, they are melted down in Rans- over nearly 35 years, enables AMAG materials in a professional manner composition that the starting material had, not recognizable as valuable recyclables by hofen and used in alloy-to-alloy recycling. to process aluminium scrap into high- 2) Storing correctly sorted raw material un- or one very similar to it. The second point is the layman - that are processed in Ransho- Products of daily use such as wine closures, Iquality alloys. The ever-increasing de- der roof accepting a certain level of impurities wit- fen to obtain high-grade cast and wrought cans, tubes, yogurt lids, bottle caps and mands being placed on the products will 3) Adding as much value as possible hout a negative effect on properties. These alloys. Motor cars, for instance, are a rich foils are processed as well. Due to their Rotary furnace continue to require AMAG to deal, com- through alloy-to-alloy recycling recycling-friendly cast and wrought alloys source of raw materials: engine blocks, high plastics content, such materials make prehensively and in depth, with scrap as a 4) Maximizing output by means of batch are being developed in cooperation with gear boxes, wheel rims, radiators, body very high demands on the melting process. valuable material. At the Ranshofen loca- calculation for each melting furnace partners. sheets, license plates, etc., even production tion, 260,000 tons of scrap were used as 5) Ensuring sustainability in all production waste (e.g. gating systems), are recycled at Even aluminium that is tossed into the trash input material last year. The material is de- processes 1) Checking of incoming materials AMAG. bin (e.g. cans) ultimately finds its way to livered in various forms (see illustration 1), 6) Detailed knowledge of the influence of Before entering AMAG's premises, any AMAG as the ashes from waste incinerati- from correctly sorted, clean, external indus- the chemical composition on material materials are automatically checked for ra- This also applies to the civil engineering on are sorted and the corresponding alumi- trial waste, which has similar properties and properties dioactivity. It is only after passing that test and building industries; take, for example, nium fraction can be recycled. However, it values as ingot material, to highly oxidic and 7) Developing recycling-friendly materials that further samples of the material are in- casements (whether pre-consumer scrap or is more expedient to separate beforehand. Tiltable rotary furnace organically contaminated dross skimmings spected, especially as regards its composi- post-consumer scrap from building demo- and chips, which are cheaper to buy but Recycling at AMAG tion. lition and renovation), or aluminium molds 2) Storing correctly sorted raw materi- with large surface portions must be stored place high demands on process control and Goal: alloy-to-alloy for clay roof tiles, supports, casings, tread- al under roof in a dry place; otherwise the aluminium output. In that area of conflicting priorities, If one consistently practices the above Whereas for many cast alloys AMAG chiefly plates, etc. Subsequently, the scrap is sorted both would corrode and be lost. Pure scrap in AMAG attempts to process the input ma- points, alloy-to-alloy recycling is possible. uses scraps it is obvious that for certain according to chemical composition and lumps can be stored in the open for a short terial in an optimum manner. T his means, That is, scrap is not used to produce alu- wrought alloys where a high degree of pu- Modern printing processes, e.g. for maga- morphology, and stored in dedicated sto- period of time. The logistics behind this is for example: minium of unspecific composition but, in- rity is required these can be employed to zines, use aluminium lithographic plates. rage areas. Particularly small-sized scrap one of AMAG's core competences. a limited extent only. Optimum use of the charged material presupposes thorough in- spection of samples and proper separation. For this reason, a representative sample is drawn from each delivery, and a chemical analysis is performed. 14 AluReport 02.2012 Recycling 15
3) Alloy-to-alloy recycling tion [1]. 16 differentiated analysis programs scraps described in item 2 is an essential 7) Enhancement of recycling expertise limits, however, can only be carried out in An important aspect in alloy-to-alloy re- ensure that the chemical composition can condition. Organic contamination (coat- and development of recycling-friendly close coordination with the user because cycling is sophisticated metal analysis by be measured correctly. ings, paints, foils, etc.) can be a particular materials each finished product places individual de- which the chemical composition of alloys problem when scrap is to be recycled into Despite considerably larger quantities pro - mands on the material. can be determined. AMAG has recently At this point, all AMAG customers benefit high-quality materials. Correct charging al- cessed at the Ranshofen location, AMAG invested in this important area. This fully from the rigorous certification standards of lows the contaminants to be burned off in a is aiming to maintain or, if possible, even It is AMAG's declared intention to increas- automated facility includes two spark emis- the aircraft industry. For example, approval controlled manner and reduces the expens- increase the high scrap charge rate. To ingly work on the development and im- sion spectrometers of maximum precision analyses of cast alloys are kept for at least es related to the required post-combustion achieve this goal, AMAG needs larger quan- provement of recycling-friendly alloys, Final steps (Illustration 2). Additionally, samples from two years, those of wrought alloys for at to comply with Austria's stringent emission tities of scrap, which is converted to high- jointly with customers and research in- Cutting and packing accord- the melting furnace undergo another radio- least ten years. Even test specimens that regulations. Moreover, the heat generated quality cast and rolled products. So, when stitutes, to continue encouraging the re- ing to customer specifications activity check. describe the melting history of the material can be used for the melting process, thus expanding its plant, AMAG will also expand source-efficient production of lightweight and dispatch conclude the up to the product, so-called approval sam- saving CO2 [2]. the Recycling Center Ranshofen. components through the recycling route. processing of the order. AMAG's Ranshofen site is the only produc- ples, are retained for one month to be able tion facility worldwide to process all alloy to answer questions, if any. The test speci- 5) Sustainability in all processes AMAG is focusing on increasing the range Outlook families from 1xxx to 8xxx at a single loca- men is automatically labeled for traceability AMAG gives top priority to minimizing envi- of recyclable input materials, thus enhanc- The "AMAG 2014" investment project with the batch number, material number ronmental impact and energy input. During ing its recycling expertise step by step. This will cause AMAG to grow signifi- and equipment number, as well as date and recent years, all melting furnaces have been means that AMAG also processes scraps cantly. The current scrap charge rate time of measurement, using a marking sys- converted to regenerative burner technol- containing large amounts of organic con- will be maintained, which will lead tem, and entered in the database. ogy [3] (install FILTER). As a result, the emis- taminants and other nonmetallic impurities to more aluminium scrap being sion values are well below the Austrian limit (oxides, dust, etc.), and returns them to the processed. For this reason, the l For special elements or to be on the safe values, which are among the strictest in the product cycle. Ranshofen Recycling Center is i side, AMAG can also perform wet-chemical world. Besides, the cooling water for the being further expanded. o ICP (induced coupled plasma) analyses. At continuous casting process is recirculated to Recycled aluminium normally contains trace any rate, it is ensured that the sampling minimize environmental impact. AMAG is elements that do not occur in the electrolytic c standards used are always the same, from certified according to ISO 14001. metal, and may also contain alloying ele- the inspection of samples to the finished ments such as iron, copper and zinc that ex- product. This way a 6xxx alloy can again be 6) Detailed knowledge of the influence ceed the tolerance limits of alloy standards. m recycled into a 6xxx alloy. of the chemical composition on mate- To be able to use recycling alloys even more Rolling and heat treatment u Numerous production stages - e.g. Illustration 2: fully automated metal analysis rial properties widely in sophisticated aluminium compo- i 4) High-quality recycling by charge cal- When scrap is processed into alloys, undesir- nents, it is essential to have full knowledge of rolling, heat treatment, cutting, culation for each melting furnace ably high amounts of trace elements and al- the effects of these elements, including their n testing - are needed in the roll- Adequate melting technologies are the key loying elements, if any, are bound to be car- interactions, to then challenge the necessity i ing mill in order to produce to optimum recycling. AMAG has a wide ried into the material. Therefore, it is particu- of the close tolerance limits. For example, aluminium strip. range of melting furnaces (shaft furnaces, larly important to know their impact on the a slight increase of the permissible copper m hearth-type furnaces, rotary drum-type material properties. Such elements can have content can lead to a marked increase u furnaces, rotary-drum tilting-type furnaces; an influence on the mechanical properties, of the possible scrap charge, without l see Illustration 1). The art of recycling con- such as yield point, tensile strength, elonga- having a noticeable impact on a sists in allocating the optimum scrap mix to tion, dynamic characteristics, as well as on the corrosion properties. the appropriate melting unit, based on the the correct heat treatment parameters and This deliberate exten- o workability at AMAG and at the customer. requirements of the finished product. A da- sion of the alloy t The process parameters and properties of the tabase-aided charge calculation that takes tolerance p finished product can only be specifically set if into account the types and amounts of the a the chemical composition is fully known. cr Aluminium scrap s Scrap from cans, foils, wheel rims, win- m dow frames, façades, engine blocks, body iu Casting sheets, chips, process scrap, etc., is col- in Fr um Advanced casting technology provides high-quality lected, classified and stored sorted by type o m al Contact for more information: basic material for subsequent processes. For to the greatest possible extent. instance: rolling slabs of optimum form, Dr. Werner Fragner Melting dimension and chemical composition. Phone: +43 7722 801 2835 [email protected] At Ranshofen, approximately 80% of Optimally tailored to customer AMAG's high-quality products are made requirements.
from scrap material. This high scrap charge Literature rate can only be achieved through special [1] AMAG AluReport 1/2008, page 15 [2] Suppan, Umweltfreundliche Schmelzöfen in der know-how and sophisticated metal analysis. Aluminiumindustrie, 5. Ranshofener Leichtmetalltage, Seite 25ff, ISBN-13: 978-3-902092-05-2