Extractive Metallurgy of Copper Part 6 pot

A usnwlt/lsasndt Matte Smelting 127 (c) Sterlite smelter, Tuticorin, India (1995) (d) Union Miniere secondary copper smelter, Chapter 22, Hoboken, Belgium (I 997) (e) Yunnan Copper smelter under construction at Kunming, China (startup 200 1 ). 8.7 Other Coppermaking Uses of Ausmelt/Isasmelt Technology AusmeltiIsasmelt smelting is the outgrowth of technology originally designed for use in tin smelting (Robilliard, 1994). Ausmelt in particular have been active since then in developing uses for their furnace beyond sulfide matte smelting (Hughes, 2000). One of these is matte converting, which has been demonstrated on a small scale. The Ausmelt furnace for converting is similar to that used for smelting (Mounsey et al., 1999). In fact, in small smelters, smelting and converting can be performed in the same furnace (Mounsey et al., 1998). The matteislag mixture produced by smelting is allowed to settle, the slag is tapped, and the lance is reinserted into the matte for converting. A two-step process is used. It begins by converting the matte to molten Cu,S (white metal) followed by tapping slag. It is finished by oxidizing the Cu,S to copper and SO,. As in the case of smelting, magnetite in the slag appears to act as a catalyst for the converting reactions. The process is autothermal, although some coal is added to reduce the copper oxide content of the slag to about 15% Cu. The first Ausmelt furnace specifically dedicated to matte converting recently came on-line in the Houma copper smelter in China (Mounsey et al., 1999). Unfortunately, discontinuous two-step smelting/converting sends an intermittent stream of SO, to acidmaking. For this reason, it is unlikely to become prominent. Ausmelt technology is also usehl for recovering copper from non-sulfide materials, particularly slags and sludges (Hughes, 2000). Its ability to control air and fucl inputs means that conditions can be changed from oxidizing to reducing without transferring material to a second furnace. This is particularly effective for smelting Cu/Ni hydrometallurgical residues. 8.8 Summary Ausrnelt and Isasmelt smelting is done in vertically aligned cylindrical furnaces 128 Extractive Metallurgy of Copper -3.5 m diameter and 12 m high. The smelting entails: (a) dropping moist concentrate, flux and recycle materials into a molten matteklag bath in a hot furnace (b) blowing oxygen-enriched air through a vertical lance into the matte/slag bath. Most of the energy for smelting is obtained from oxidizing the concentrate's Fe and S. The vertical lance consists of two pipes - the inner for supplying supplementary hydrocarbon fuel, the annulus for supplying oxygen-enriched air. The outer pipe penetrates -0.3 m into the bath. The inner pipe ends -1 m above the bath. The oxygen-enriched blast is swirled down the lower part of the lance by helical swirl vanes. This causes rapid heat extraction from the lance into the cool blast and solidification of a protective slag coating on the lance's outer surface. This is a unique feature of the process. The principal product of the furnace is a matteislag mixture. It is tapped into a hydrocarbon fired or electric settling furnace. The products after settling are 60% Cu matte and 0.7% Cu slag. The main advantages of the process are: (a) its small 'footprint', which makes it easy to retrofit into existing smelters (b) its small evolution of dust. The 1990's and early 2000's saw Ausmelt and Isasmelt smelting adopted around the world. It should soon account for 5% of world copper smelting. The future may see dry concentrate injection through the lance. improve the thermal efficiency of the process. This will Suggested Reading Binegar, A.H. (1995) Cyprus Isasmelt start-up and operating experience. In Copper95 Cobre 95 Proceedings of the Third International Conference, Vol. IV Pyrometallurgy of Copper, ed. Chen, W.J., Diaz, C., Luraschi, A,, and Mackey, P.J., The Metallurgical Society of CIM, Montreal, 117 132. Mounsey, E.N., Li, H., and Floyd, J.W. (1999) The design of the Ausmelt technology smelter at Zhong Tiao Shan's Houma smelter, People's Republic of China, in Copper 99- Cobre 99 Proceedings of the Fourth International Conference, Vol. V Smelting Operations and Advances, ed. George, D.B., Chen, W.J., Mackey, P.J., and Weddick, A.J., TMS, Warrendale, PA, 357 370. Ausmelt/lsasmelt Matte Smelting I29 Player, R.L., Fountain, C.R., Nguyen, T.V., and Jorgensen, F.R. (1992) Top-entry submerged injection and the Isasmelt technology. In SavardILee International Symposium on Bath Smelting, ed. Brimacombe, J.K., Mackey, P.J., Kor, G.J.W., Bickert, C., and Ranade, M.G., TMS, Warrendale, PA, 215 229. References Ausmelt Commercial Operations (2002) http://www.ausmelt.com.au/comops.html Binegar, A.H. (1995) Cyprus Isasmelt start-up and operating experience. In Copper95- Cobre 95 Proceedings ofthe Third International Conference, Vol. IV Pyrometallurgy of Copper, ed. Chen, W.J Diaz, C., Luraschi, A., and Mackey, P.J., The Metallurgical Society of CIM, Montreal, 117 132. Hughes, S. (2000) Applying Ausmelt technology to recover Cu, Ni, and Co from slags, JOM, 52 (8), 30 33. Isasmelt Installations (2002) http://www.mimpt.com.au/isasmelt-installations.html Isasmelt Technology (2002) http://www.mimpt.com.au/isasmeIt-technology.htm1 Mounsey, E.N., Floyd. J.M., and Baldock, B.R. (1998) Copper converting at Bindura Nickel Corporation using Ausmelt technology. In Sulfide Smelting ’98, ed. Asteljoki, J.A., and Stephens, R.L., TMS, Warrendale, PA, 287 301. Mounsey, E.N., Li, H., and Floyd, J.W. (1999) The design of the Ausmelt technology smelter at Zhong Tiao Shan’s Houma smelter, People’s Republic of China. In Copper 99- Cobre 99 Proceedings of the Fourth International Conference, Vol. V Smelting Operations and Advances, ed. George, D.B., Chen, W.J., Mackey, P.J., and Weddick, A.J., TMS, Warrendale, PA, 357 370. Mounsey, E.N., and Robilliard, K.R. (1 994) Sulfide smelting using Ausmelt technology. JOM, 46 (8), 58 60. Player, R.L. (1996) Copper Isasmelt - Process investigations. In Howard Worner International Symposium on Injection in Pyrometallurgy. ed. Nilmani, M. and Lehner, T., TMS, Warrendale, PA, 439 446. Pritchard, J.P and Hollis R. (1994) The Isasmelt copper-smelting process. Int. Miner. Met. Technol 1, 125 128. Robilliard, K. (1994) The development of Sirosmelt, Ausmelt and Isasmelt. Int. Miner. Met. Technol., 1, 129 134. Solnordal, C.B. and Gray, N.B. (1996) Heat transfer and pressure drop considerations in the design of Sirosmelt lances. Met. and Mater. Trans. E, 27B (4), 221 230. CHAPTER 9 Batch Converting of Cu Matte Converting is oxidation of molten Cu-Fe-S matte to form molten 'blister' copper (99% Cu). It entails oxidizing Fe and S from the matte with oxygen-enriched air or air 'blast'. It is mostly done in the Peirce-Smith converter, which blows the blast into molten matte through submerged tuyeres, Figs. 1.6 and 9.1. Several other processes are also used or are under development, Section 9.6 and Chapter 10. The main raw material for converting is molten Cu-Fe-S matte from smelting. Other raw materials include silica flux, air and industrial oxygen. Several Cu- bearing materials are recycled to the converter - mainly solidified Cu-bearing reverts and copper scrap. The products of converting are: (a) molten blister copper which is sent to fire- and electrorefining (b) molten iron-silicate slag which is sent to Cu recovery, then discard (c) SOz-bearing offgas which is sent to cooling, dust removal and &So4 manufacture. The heat for converting is supplied entirely by Fe and S oxidation, Le. the process is autothermal. 9.1 Chemistry The overall converting process may be described by the schematic reaction: Cu-Fe-S + 0, + Si02 + Cu; + molten in air and in flux molten slag with (9.1). matte oxygen somesolid Fe304 131 [...]... 36 5.08 three 4.5 x 10 .6 one 4.0 x 10 .6 48 46 6.35 700 750 350-558 350-558 only copper blow 60 0 730 770 23. 26 25 none 23. 26 7.5 25 12 21 15 2 1, then 60 min at 26% O2 21 21 1 (66 .5% Cu)+73 WM Outokumpu flash furnace + Teniente furnace 180 (62 % Cu) Outokumpu flash furnace 200 (74.3% CU) Teniente & slag cleaning furnaces 230 (63 % Cu) Outokumpu flash furnace I S t mostly reverts 5.8 tonnes of reverts 60 ... tonnes reverts 40t Cu scrap etc 145 30 25 195 63 6. 5 0.48 x 10 .67 I 30t Cu scrap etc 210 66 8 x 11.4 180 56 3 0.5 1 4.2 x 11.9 58 5 11 6. 61 2 .66 3.0 8 .6 1.75 3.91 7 to 7.5 none 5 9 .6 120 125 tuyere & body 95 40 000 54 000 30 tuyere line (I80 tuyere line &body) 1 I200 45 400 2.0 4.5 2-3 1.5 1 2.5 L.J L.LJ 1.5 3.3 c P 0 Table 9.3 Representative analyses of converter raw materials and products, mass%... feed distribution YO to blister copper to converter slag to converter offgas blister copper 28 13 4 29 72 11 13 17 48 7 6 86 58 67 46 64 21 3 50 55 5 59 70 8 to to converter slag to converter offgas 32 23 49 26 5 18 22 46 15 25 I9 13 For this reason, some smelters treat the dusts for impurity removal before they are recycled (Shibasaki and Hayashi, 1991) Bismuth, in particular, is removed because (i)... of the tuyeres They also indicate that tuyere blockage is discouraged by high matte temperature and oxygen-enrichment of the blast This is particularly important near the end of the slag blow and the start of the copper blow Clear tuyere conditions at the beginning of the copper blow often give ‘free blowing’ conditions (without punching) during most or all of the copper blow (Photograph courtesy of. .. tuyeres of a Peirce-Smith copper converter Canadian Metallurgical Quarterly, 27(1), 7 21 Bustos, A.A., Brimacombe, J.K., Richards, G.G., Vahed, A and Pelletier, A (1987) Developments of punchless operation of Peirce-Smith converters In Copper 87, Vol 4, Pyrometallurgy of Copper, ed Diaz, C., Landolt, C and Luraschi, A., Alfabeta Impresores, Lira 140, Santiago, Chile, 347 373 152 Extractive Metallurgy o Copper. .. Floyd, J.M., TMS, Warrendale, PA, 1 58 Marcuson, S.W (1993) Copper converting - an historical perspective CIM Bulletin, 86( 966 ), 92 96 Taylor, J.C and Traulsen, H.R (1987) World Survey of Nonferrous Smelters, TMS, Warrendale, PA Vemey, L.R (1987) Peirce-Smith copper converter operations and economics In Copper 87, Vol 4, Pyrometallurgy o Copper, ed Diaz, C., Landolt, C and Luraschi, A,, Alfabeta f... number of tuyeres total active tuyere diameter, cm usual blast rate per converter slag blow, Nm’lminute copper blow, Nm3/minute usual volume% 0 2 in blast slag blow 5 3 2 4 3 2 4 .6 12.2 62 60 6 four: 3. 96 x 9.15 one: 3. 96 x 1 I O 48 44 5 x 700 s20 700-800 500 23 2 I , then 60 minutes at 29 Production details (per converter) Inputs (tonnesicycle) molten matte source Other inputs (tonnes) slag blow copper. .. secondaries copper blow SO2 in offgas, volume% +2St reverts 50t Cu scrap etc 75t Cu scrap 120 I50 5 0 .63 9 2 4.5 13 60 100 50 000 21 60 0 1 1.93 5 3 139 Batch Converting ofCu Matte Peirce-Smith and Hoboken converters Mexicana de Cobre Nacazari, Mexico Caraiba Metals Bahia, Brazil CODELCO Caletones, Chile Sumitomo Toyo, Japan Peirce-Smith Hoboken Peirce-Smith Peirce-Smith 3 2 3 2 4 3 3 2 1 or2 4.57 4. 16 56 56. .. 02-in-matte residence time 1 46 Extractive Metallurgy of Copper 9.4.1 Maximizing solids melting An important service of the Peirce-Smith converter is melting of valuable solids with the heat from the converting reactions The most usual solids are (i) Cubearing revert materials; (ii) scrap copper and (iii) Au and Ag flux Cu concentrate is also melted in several smelters Melting of solids is maximized by:... temperature measurement In Copper 87, Vol 4, Pyrometallurgy o Copper, ed Diaz, C., Landolt, C and Luraschi, A,, Alfabeta Impresores, Lira 140, Santiago, Chile, 375 391 Peretti, E.A (1948) An analysis of the converting of copper matte Discuss Faraday Soc., 4, 179 184 Persson, W., Wendt, W and J Demetrio, S (1999) Use of optical on-line production f control in copper smelters In Copper 99-Cobre 99 Proceedings . converter copper slag offgas 28 13 58 13 17 67 4 48 46 29 7 64 72 6 21 11 86 3 70% Cu matte feed distribution YO to to to blister converter converter copper slag offgas 50. Cu scrap etc. 210 66 8 6. 61 2 .66 3.0 120 40 000 1 Caraiba Metals Bahia, Brazil Hoboken 3 2 4. 16 x 11.4 42 36 5.08 350-558 350-558 25 25 12 180 (62 % Cu) Outokumpu. Converting ofCu Matte 139 Peirce-Smith and Hoboken converters. Mexicana de Cobre Nacazari, Mexico Peirce-Smith 3 2 1 or2 4.57 x 10 .67 56 56 5 700 750 23. 26 23. 26 7.5 21 1 (66 .5%