The Effect of Regrinding Chemistry and Particle Breakage Mechanisms on Subsequent Cleaner Flotation Xumeng Chen Beng and Meng in Materials Engineering

Total Page:16

File Type:pdf, Size:1020Kb

The Effect of Regrinding Chemistry and Particle Breakage Mechanisms on Subsequent Cleaner Flotation Xumeng Chen Beng and Meng in Materials Engineering The Effect of Regrinding Chemistry and Particle Breakage Mechanisms on Subsequent Cleaner Flotation Xumeng Chen BEng and MEng in Materials Engineering A thesis submitted for the degree of Doctor of Philosophy at The University of Queensland in November 2014 Sustainable Minerals Institute Julius Kruttschnitt Mineral Research Centre Abstract Regrinding rougher flotation concentrates is typically used to liberate valuable minerals from gangue prior to the cleaner separation stage in processing of low grade ores. Compared to the rougher flotation after primary grinding, it is usually more challenging to achieve a satisfactory performance in post-regrind cleaner flotation especially when fine particles are generated. One main factor which results in this reduction in flotation is the unsuitable particle surfaces produced after regrinding. However, this factor is not usually considered when designing and optimizing the regrinding process. Extensive studies have demonstrated that grinding chemistry can influence mineral floatability. However, earlier studies focused on primary grinding and rougher flotation rather than regrinding and cleaner flotation. In addition, different types of regrind mills are used in industry, and these provide different particle breakage mechanisms which may also influence mineral floatability. Therefore, the overall objective of this thesis study is to investigate the effects of regrinding chemistry and particle breakage mechanisms on the cleaner flotation. The implementation of regrinding in the copper and pyrite flotation circuits at Telfer gold mine was taken as a case study and four research areas were addressed with the objective of developing fundamental understanding to provide practical guidance for the plant operation. The four areas investigated are: 1. Effect of regrinding chemistry on copper activation of pyrite and its flotation; 2. Separation of different copper sulphide minerals from pyrite after regrinding; 3. Importance of pulp chemistry during regrinding rougher concentrates; 4. Effect of particle breakage mechanisms on subsequent flotation. In this study, it was found that copper activation of pyrite and its flotation in the cleaner stage were affected by regrinding. In general, a decrease in surface concentration of collectors due to the increased surface area after regrinding contributed to the low pyrite recovery in the cleaner. Surface analysis revealed that both the surfaces that were carried from the rougher flotation concentrate and those which were freshly created were modified by the strong electrochemical reactions occurring inside the regrind mill. Stainless steel media promoted pyrite oxidation, especially on the copper activated surfaces. Mild steel media produced a greater amount of iron oxidation species which could adsorb on the carried surfaces. It was also found that mild steel media generated a reducing condition which favoured the copper activation on the freshly created surfaces. i The research has also shown that the separability of chalcopyrite and chalcocite from pyrite was significantly different after regrinding, which was related to their electrochemical properties. Chalcocite was more active and therefore presented a stronger galvanic interaction with pyrite. Consequently chalcocite was more oxidised, which not only depressed its flotation but also produced sufficient copper ions to activate pyrite, making the separation of chalcocite from pyrite more difficult. In comparison, chalcopyrite was less active. Its oxidation generated hydrophobic surfaces which improved chalcopyrite floatability. At the same time pyrite flotation was depressed due to the insufficient copper ions for activation, leading to an effective separation of chalcopyrite from pyrite. However, these flotation differences were not significant at the rougher stage and this was thought to be due to weak galvanic interactions at the coarser particle sizes present in this stage of the process. A pulp chemistry survey at Telfer indicated extremely low dissolved oxygen concentration and Eh after regrinding of pyrite concentrate resulting in poor subsequent copper and gold flotation. To develop a remedial strategy, the plant flotation conditions and performance were replicated in the laboratory and several methods were examined to increase the oxidising condition. It was found that oxidising conditions were beneficial to copper-gold flotation and pyrite depression. The surface analysis showed that the improved flotation was attributed to a combined effect of several factors, including pyrite surface oxidation which reduced its floatability, increased collector adsorption on copper-gold surfaces, and also the oxidation of chalcopyrite producing hydrophobic species. Apart from the regrinding chemistry, another important factor considered in this study was the type of grinding mills which provide different particle breakage mechanisms. A significantly lower recovery was observed after regrinding in a stirred mill than in a rod mill. After examining all possible factors influencing the flotation, it was found that the predominating factor was the different distribution of collectors remaining from rougher flotation concentrates. In the tumbling mill, impact breakage dominated, causing the collector to remain on the surface of newly produced particles. In the stirred mill, attrition breakage removed collector from the surface, and decreased particle floatability. This was further confirmed by the analysis of collector intensity on mineral surfaces on a size-by-size basis by ToF-SIMS. Overall, the results of this thesis study clearly show that both regrinding chemistry and particle breakage mechanisms play critical roles in changing pulp chemistry and the formation and ii distribution of surface species and hence affect mineral flotation and separation in the subsequent cleaner flotation. iii Declaration by author This thesis is composed of my original work, and contains no material previously published or written by another person except where due reference has been made in the text. I have clearly stated the contribution by others to jointly-authored works that I have included in my thesis. I have clearly stated the contribution of others to my thesis as a whole, including data analysis, survey design, significant technical procedures, professional editorial advice, and any other original research work used or reported in my thesis. The content of my thesis is the result of work I have carried out since the commencement of my research higher degree candidature and does not include a substantial part of work that has been submitted to qualify for the award of any other degree or diploma in any university or other tertiary institution. I have clearly stated which parts of my thesis, if any, have been submitted to qualify for another award. I acknowledge that an electronic copy of my thesis must be lodged with the University Library and, subject to the General Award Rules of The University of Queensland, immediately made available for research and study in accordance with the Copyright Act 1968. I acknowledge that copyright of all material contained in my thesis resides with the copyright holder(s) of that material. Where appropriate I have obtained copyright permission from the copyright holder to reproduce material in this thesis. iv Publications during candidature Peer-reviewed journal publications relevant to the thesis: Chen. X., Peng. Y. and Bradshaw, D., 2013. Effect of regrinding conditions on pyrite flotation in the presence of copper ions. International Journal of Mineral Processing 125: 129-136. Chen, X., Peng, Y. and Bradshaw, D., 2014. The separation of chalcopyrite and chalcocite from pyrite in cleaner flotation after regrinding. Minerals Engineering 58: 64-72. Chen, X., Seaman, D., Peng, Y. and Bradshaw, D., 2014. Importance of oxidation during regrinding of rougher flotation concentrates with a high content of sulphides. Minerals Engineering 66-68: 165-172. Chen, X., Peng, Y. and Bradshaw, D., 2014. The effect of particle breakage mechanisms during regrinding on the subsequent cleaner flotation. Minerals Engineering 66-68: 157-164. Additional peer-reviewed conference publications relevant to the thesis: Chen, X., Peng, Y. and Bradshaw, D., 2012. Effect of regrinding conditions on the rejection of pyrite in the cleaner stage. 26th International Mineral Processing Congress, New Delhi, India, pp. 877-887. Chen, X., Peng, Y. and Bradshaw, D., 2012. Effect of regrinding conditions on the flotation of chalcopyrite and its separation from pyrite in the cleaner stage. 11th AusIMM Mill Operators' Conference, Hobart, Tasmania, pp. 279-286. Chen, X., Peng, Y. and Bradshaw, D., 2014. Effect of regrinding conditions on the flotation of sulphide minerals in the cleaner stage. 27th International Mineral Processing Congress, Santiago, Chile, Chapter 2, pp. 11-22. v Publications included in this thesis Chen. X., Peng. Y. and Bradshaw, D., 2013. Effect of regrinding conditions on pyrite flotation in the presence of copper ions. International Journal of Mineral Processing 125: 129-136. Contributor Statement of contribution Xumeng Chen (Candidate) Conception and design (60%) Analysis and interpretation of data (70%) Wrote the paper (70%) Dr. Yongjun Peng Conception and design (30%) Analysis and interpretation of data (20%) Wrote the paper (30%) Prof. Dee Bradshaw Conception and design (10%) Analysis and interpretation of data (10%) Chen, X., Peng, Y. and Bradshaw, D., 2014. The separation of chalcopyrite
Recommended publications
  • From Base Metals and Back – Isamills and Their Advantages in African Base Metal Operations
    The Southern African Institute of Mining and Metallurgy Base Metals Conference 2013 H. de Waal, K. Barns, and J. Monama From base metals and back – IsaMills and their advantages in African base metal operations H. de Waal, K. Barns, and J. Monama Xstrata IsaMill™ technology was developed from Netzsch Feinmahltechnik GmbH stirred milling technology in the early 1990s to bring about a step change in grinding efficiency that was required to make Xstrata’s fine-grained lead/zinc orebodies economic to process. From small-scale machines suited to ultrafine grinding, the IsaMill™ has developed into technology that is able to treat much larger tonnages, in coarser applications, while still achieving high energy efficiency, suited for coarser more standard regrind and mainstream grinding applications. The unique design of the IsaMillTM, combining high power intensity and effective internal classification, achieves high energy efficiency and tight product distribution which can be effectively scaled from laboratory scale to full-sized models. The use of fine ceramic media also leads to significant benefits in downstream flotation and leaching operations. These benefits are key drivers for the adoption of the technology into processing a diverse range of minerals worldwide, and offer major opportunities for power reduction and improved metallurgy for the African base metal operations. Keywords: IsaMill, regrind, energy efficiency, inert grinding. Introduction The development of the IsaMillTM, by MIM (now GlencoreXstrata) and Netzsch Feinmahltechnik GmbH, was initiated to enable the development of the fine-grained ore deposits at Mt Isa and McArthur River in Northern Australia. To liberate the valuable minerals and so produce a saleable concentrate this ultrafine-grained ore needed to be ground to a P80 of 7 μm.
    [Show full text]
  • Challenges Related to the Processing of Fines in the Recovery of Platinum Group Minerals (Pgms)
    minerals Review Challenges Related to the Processing of Fines in the Recovery of Platinum Group Minerals (PGMs) Kirsten C. Corin 1,* , Belinda J. McFadzean 1, Natalie J. Shackleton 2 and Cyril T. O’Connor 1 1 Centre for Minerals Research, Chemical Engineering Department, University of Cape Town, P Bag X3, Rondebosch, Cape Town 7700, South Africa; belinda.mcfadzean@uct.ac.za (B.J.M.); cyril.oconnor@uct.ac.za (C.T.O.) 2 Minerals Expertise Tech Pty Ltd., Germiston 2007, South Africa; natalieshackleton0@gmail.com * Correspondence: Kirsten.Corin@uct.ac.za Abstract: In order to increase the recovery of PGMs by flotation, it is necessary to optimise the liberation of the key minerals in which the platinum group elements (PGEs) are contained which include sulphides, arsenides, tellurides, and ferroalloys among others, while at the same time ensuring the optimal depression of gangue minerals. In order to achieve this, comminution circuits usually consist of two or three stages of milling, in which the first stage is autogeneous, followed by ball milling. Further liberation is achieved in subsequent stages using ultra-fine grinding. Each comminution stage is followed by flotation in the so-called MF2 or MF3 circuits. While this staged process increases overall recoveries, overgrinding may occur, hence creating problems associated with fine particle flotation. This paper presents an overview of the mineralogy of most of the more significant PGM ores processed in South Africa and the various technologies used in comminution circuits. The paper then summarises the methodology used in flotation circuits to optimise recovery Citation: Corin, K.C.; McFadzean, of fine particles in terms of the collectors, depressants, and frothers used.
    [Show full text]
  • Evolution of the Isamill™ Into Magnetite Processing
    EVOLUTION OF THE ISAMILL™ INTO MAGNETITE PROCESSING Greg Rasmussen, Xstrata Technology Pty Ltd Tommy Do , Ernest Henry Mining Michael Larson, Xstrata Technology Pty Ltd Katie Barns, Xstrata Technology Pty Ltd Xstrata Technology • Mount Isa Mines (MIM), a large Australian mining company, was acquired by Xstrata in 2003 who then merged with Glencore in 2013 • MIM internal technology group was re-named Xstrata Technology (XT) and became an independent technology developer and supplier to the global minerals industry with 250 staff worldwide • The equipment and processes which are marketed by XT are developed in our own operations • XT offers full-package solutions including: • Equipment and processes • Engineering • Commissioning and Training • Dedicated after-market support IsaMill™ Technology Development ™ • Development of IsaMill driven by inability Broken Hill to efficiently treat fine grained orebodies • Late 1980s, Xstrata required 7µm grind for new Pb/Zn orebodies in Australia • Conventional mining technologies tested (1975-1990), but 0 40 micron − Too high power consumption to achieve target size McArthur River − Ball/tower mills ineffective below 20-30μm − Negative influence of steel grinding on flotation 0 40 micron IsaMill™ Technology Development A technology was found... • Horizontal Bead Mills − Used in industries other than mining (pharmaceuticals, paint, food, etc.) − Small, batch scale − Very expensive and exotic media types • Cross-over into mining required: − Much larger scale − Continuous operation − Ability to use cheap,
    [Show full text]
  • Regrinding and Fine Grinding Technology - the Facts and Myths
    A review of regrinding and fine grinding technology - the facts and myths Dr Alex Jankovic, Metso Minerals Process Technology Asia-Pacific, alex.Jankovic@metso.com ABSTRACT Stirred milling technology is used extensively for fine grinding in the ceramic, paint and pharmaceutical industrials. It has been recently adopted by the mining industry. Specific conditions in the mining industry require somewhat different operation of this technology. However, the basic principles of operation are the same and the accumulated knowledge and experience developed in these other industries could be used to assist mining operations to get the most benefit from the stirred milling technology. This paper presents some of the important aspects of stirred milling operation discussed in the literature and not commonly known within the mining industry: grinding media motion, active grinding volume, wear of grinding media and energy transfer, stress intensity, scale-up issues and flow limitations. The intention is to introduce a “different perspective” of stirred milling technology, in particular highlighting its potential benefits and limitations. HISTORY Stirred milling technology may be regarded as relatively new in minerals processing, however it is a mature and extensively used technology in the ceramic, paint and pharmaceutical industries. The latest development of this technology is in the area of “Nano-grinding” for grinding down to nano-sizes. One may say that stirred mills used today in mining and minerals processing are equivalent to the early models of stirred mills used in parallel industries. The most commonly used stirred mills in mining and minerals processing are the VERTIMILL®, STIRRED MEDIA DETRITOR (SMD®) and ISAMILL® and a brief history of their development is given below.
    [Show full text]
  • Isamill™ Technology Used in Efficient Grinding Circuits
    1 IsaMill™ Technology Used in Efficient Grinding Circuits B.D. Burford1 and L.W. Clark2 High intensity stirred milling is now an industry accepted method to efficiently grind fine and coarse particles. In particular, the IsaMill™, which was invented for, and transformed the fine grinding industry, is now being included in many new comminution circuits in coarser applications. While comminution has always been regarded as important from a processing perspective, the pressure being applied by environmental concerns on all large scale power users, now make highly energy efficient processes more important than ever. The advantages that were developed in fine grinding in the early IsaMill™ installations have been carried over into coarse grinding applications. These advantages include a simple grinding circuit that operates in open circuit with a small footprint, the ability to offer sharp product size classification, as well as the use of inert media in a high energy intensive environment. This paper will examine the use of IsaMill™ technology in fine grinding (P80 below 15 micron), and examine the use of the technology in conventional grinding applications (P80 20 - 150 µm). Recent installations will be examined, including fine and coarse grinding applications, as well as the recent test work that was undertaken using an IsaMill™ in a primary grinding circuit, and the resulting circuit proposal for this site. While comminution has been relatively unchanged for the last century, the need to install energy efficient technology will promote further growth in IsaMill™ installations, and result in one of the biggest challenges to traditional comminution design. 1. Senior Process Engineer, Xstrata Technology, L4, 307 Queen Street, Brisbane 4000, Qld, Australia 2.
    [Show full text]
  • Telfer Processing Plant Upgrade – the Implementation of Additional
    Telfer Processing Plant Upgrade – The Implementation of Additional Cleaning Capacity and the Regrinding of Copper and Pyrite Concentrates D R Seaman1, F Burns2, B Adamson3, B A Seaman4 and P Manton5 ABSTRACT The Telfer concentrator, located in the Great Sandy Desert of Western Australia, consists of a dual train gold/copper operation processing ore from one underground and, currently, two open pit mines with differing mineralogy. The fl otation circuit of each train was designed to operate in several modes depending on the feed mineralogy. The majority of ore mined at Telfer is processed in a sequential mode where copper minerals are fi rst fl oated into a saleable copper concentrate followed by the fl otation of an auriferous pyrite concentrate which is treated in an on-site hydrometallurgical plant (carbon-in-leach (CIL)). Gold is recovered as a gravity product within the primary grinding circuit, to the copper concentrate, and to a lesser extent, the CIL circuit. Since Telfer was re-opened, with a new concentrator, in 2004, the processing plant has struggled with poor copper concentrate grades, partially due to the excessive entrainment of non-sulfi de gangue minerals in the copper fl otation circuit and, more recently, due to composite copper particles produced when processing ore from a supplementary satellite pit that has not previously been processed through the new Telfer concentrator. Gold recoveries in the CIL circuit have also been below industry standard. This paper presents the implementation of recent changes made to the circuit to address these performance issues. The reconfi guration of the circuit has involved the installation of the following major equipment items: two ISAMills™ in ultra-fi ne grinding applications (one in the copper circuit and one in the pyrite circuit), two Jameson Cells to improve fi ne gangue rejection and a bank of 5 × Outotec TC30s to recovery copper and gold from the reground pyrite stream.
    [Show full text]
  • Xstrata Technology Update Edition 13 – April 2012 Building Plants That Work
    xstrata technology update Edition 13 – April 2012 Building plants that work You have to get a lot of things it takes another operator to get them right to build a plant that works. right. Someone who has lived through the problems, had to do the maintenance, operated during a midnight power Of course the big picture must be right – doing the right project, in the right place, failure, cleaned up the spill. Someone at the right time. who has “closed the loop” on previous designs; lived with previous decisions After that, the devil is in the detail. You and improved them, over and over. need a sound design, good execution, good commissioning, and ongoing This is why Xstrata Technology provides support after commissioning. You need a technology “package”. Just as a car to operate and maintain your plant in is more than an engine, technology is the long run, long after the construction more than a single piece of equipment. company has left. That’s when all the Technology is a system. All the elements “little” details become important – how of the system have to work with each easy is it to operate, how good is the other and with the people in the plant. maintenance access, what happens in We want our cars designed by people a power failure, where are the spillage who love cars and driving. So should points and how do we clean them our plants be designed by people with up? Are the instruments reliable and experience and passion to make each is the process control strategy robust one work better than the last.
    [Show full text]
  • Certej Updated Definitive Feasibility Study Summary Technical Report
    Certej Updated Definitive Feasibility Study Summary Technical Report Authors:- Patrick Forward February 26th 2009 Neil Liddell Tony Jackson Certej Updated Definitive Feasibility Study Summary Technical Report Contents 3. SUMMARY ................................................................................................................................................................... 1 4. INTRODUCTION AND TERMS OF REFERENCE ................................................................................................................ 6 5. RELIANCE ON OTHER EXPERTS ...................................................................................................................................... 7 6. PROPERTY DESCRIPTION AND LOCATION ..................................................................................................................... 8 7. ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE, AND PHYSIOGRAPHY ............................................. 10 7.1. ACCESS ............................................................................................................................................................. 10 7.2. CLIMATE ........................................................................................................................................................... 10 7.3. LOCAL RESOURCES AND INFRASTRUCTURE ....................................................................................................... 10 7.4. PHYSIOGRAPHY ...............................................................................................................................................
    [Show full text]
  • The Geological Occurrence, Mineralogy, and Processing by Flotation of Platinum Group Minerals (Pgms) in South Africa and Russia
    minerals Review The Geological Occurrence, Mineralogy, and Processing by Flotation of Platinum Group Minerals (PGMs) in South Africa and Russia Cyril O’Connor 1,* and Tatiana Alexandrova 2 1 Department of Chemical Engineering, Centre for Minerals Research, University of Cape Town, Cape Town 7701, South Africa 2 Department of Minerals Processing, St Petersburg Mining University, St Petersburg 199106, Russia; alexandrovat10@gmail.com * Correspondence: cyril.oconnor@uct.ac.za Abstract: Russia and South Africa are the world’s leading producers of platinum group elements (PGEs). This places them in a unique position regarding the supply of these two key industrial commodities. The purpose of this paper is to provide a comparative high-level overview of aspects of the geological occurrence, mineralogy, and processing by flotation of the platinum group minerals (PGMs) found in each country. A summary of some of the major challenges faced in each country in terms of the concentration of the ores by flotation is presented alongside the opportunities that exist to increase the production of the respective metals. These include the more efficient recovery of minerals such as arsenides and tellurides, the management of siliceous gangue and chromite in the processing of these ores, and, especially in Russia, the development of novel processing routes to recover PGEs from relatively low grade ores occurring in dunites, black shale ores and in vanadium-iron-titanium-sulphide oxide formations. Keywords: Russia; South Africa; PGMs; geology; mineralogy; flotation Citation: O’Connor, C.; Alexandrova, T. The Geological Occurrence, Mineralogy, and Processing by Flotation of Platinum Group Minerals (PGMs) in South 1. Introduction Africa and Russia.
    [Show full text]
  • Waste Production and Utilization in the Metal Extraction Industry
    Waste Production and Utilization in the Metal Extraction Industry Waste Production and Utilization in the Metal Extraction Industry Sehliselo Ndlovu, Geoffrey S. Simate, and Elias Matinde CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2017 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed on acid-free paper International Standard Book Number-13: 978-1-4987-6729-3(Hardback) This book contains information obtained from authentic and highly regarded sources. While all reasonable efforts have been made to publish reliable data and information, neither the author[s] nor the publisher can accept any legal responsibil- ity or liability for any errors or omissions that may be made. The publishers wish to make clear that any views or opinions expressed in this book by individual editors, authors or contributors are personal to them and do not necessarily reflect the views/opinions of the publishers. The information or guidance contained in this book is intended for use by medical, scientific or health-care professionals and is provided strictly as a supplement to the medical or other professional’s own judgement, their knowledge of the patient’s medical history, relevant manufacturer’s instructions and the appropriate best practice guidelines. Because of the rapid advances in medical science, any information or advice on dosages, procedures or diagnoses should be independently verified. The reader is strongly urged to consult the relevant national drug formulary and the drug companies’ and device or material manufacturers’ printed instructions, and their websites, before admin- istering or utilizing any of the drugs, devices or materials mentioned in this book.
    [Show full text]
  • Maximum Value Minerals Processing
    ⎪ Materials handling ⎪ Maximum value minerals processing MechChem Africa talks to Cedric Walstra, Glencore Technology’s Africa business development manager, who paints a broad picture of the high-recovery, high- efficiency processing equipment on offer from the technology side of Glencore’s business. joined Xstrata Technology about cost of grinding circuits. Intense grinding ten years ago, while Glencore was a is achieved using inert ceramic grinding “ shareholder, but Glencore took us over media that leads to improved metallurgical Iabout four years ago and the name performance compared with conventional was changed to Glencore Technology,” begins steel media. Walstra, adding that Glencore Technology “Anglo Platinium has some 26 IsaMills develops, markets and supports niche tech- currently in operation. These are horizontal nologies for the global mining and minerals fine grinding mills with cantilevered shaft and processing and metals’ extraction industries, eight grinding discs. Each mill is filled to 70 to “and not only for the mines owned by the 80% of capacity with ceramic grinding beads. Above: A Jameson flotation cell in operation at Lumwana in Zambia. The system offers the highest possible Glencore Group.” As the shaft rotates, the discs and beads cause throughput in a very small footprint, with froth washing maximising the concentrate grade in a single “Glencore Technology is a standalone attrition grinding,” Walstra explains. flotation stage. Left: IsaKidd Technology, shown here in use at the Kamoto Copper Company (KCC) in the company that partners with several tech- “Kidney shaped holes in the discs allow the DRC, is the global benchmark in copper electrowinning accounting for over 11 mtpa of copper production from over 100 licensees.
    [Show full text]
  • Development of an Innovative Copper Flowsheet at Phu Kham
    Development of an Innovative Copper Flowsheet at Phu Kham M F Young and I Crnkovic Phu Kham Location in Laos Phu Kham Plant Layout Plant Layout showing • Primary Grinding • Rougher Flotation • IsaMill Regrinding Phu Kham Flowsheet GYRATORY MILL CYCLONES CRUSHER SAG MILL No.1 BALL MILL COARSE ORE STOCKPILE ROUGHER FLOTATION CELLS ROUGHER PROCESS 1st CLEANER FLOTATION CELLS CONCENTRATE WATER CYCLONES TAILINGS DAM ISAMILL 2nd CLEANER FLOTATION CELLS CONCENTRATE THICKENER 3rd CLEANER FLOTATION CELLS CONCENTRATE TANK CONCENTRATE FILTER CONCENTRATE STOCKPILE Phu Kham Flowsheet • 12.8 Mt/a of copper-gold bearing ore from the open pit • Plant Feed Grades are 0.75% Cu and 0.33g/t of Au and 3.8g/t of Ag • Concentrate quality is +25% Cu, 7 g/t of Au and 60g/t of Ag • Primary Grinding Circuit contains – 34 ft × 18 ft (13MW) SAG mill – 24 ft × 39 ft (13 MW) ball mill • Regrinding Circuit contains – M10,000 (2.6MW) IsaMill • Ore has fine locking of copper and gangue minerals • Ore requires regrinding rougher concentrate to 38 microns to make good quality final copper concentrate Cleaner Feed Performance • IsaMill currently grinds from 90 microns to 38 microns • Cleaner feed performance at 38 microns and 25 microns • Laboratory Flotation Tests Cleaner Grade-Recovery Profile For Cu-Afternoon Test 40 30 20 Cum Cu Grade 10 No Regrind (PM) With Regrind (PM) 0 20 40Cum Cu Recovery 60 80 100 New Phu Kham Flowsheet • Cleaning Circuit was overloaded at times • Fine grinding to improve concentrate quality, slowed flotation rate and increase frothing issues in
    [Show full text]