Review of Recent Developments in Pyrometallurgy P.J. Mackey A.D. Church Noranda Mines Limited Inco Metals Company Pointe Claire, Quebec, Canada Copper Cliff, Ontario, Canada 1979 ended a decade which saw significant developments increasing operating costs. These actions underline the need in process metallurgy, and when 1980 began it was evident for technology to adjust to changing technological, economic, that the coming decade would bring many changes in this and environmental factors. Several new mines in the U.S. field. This article provides a review of developments in commenced operationsl6 and new copper projects in the nonferrous process metallurgy in the last two years. U.S. were reviewed. 17 Work continued on the following Good metal prices in 1979 helped buoy the hopes of many copper projects during the year: 180,000 tpy flash smelter at that the current recession is temporary and 1981 will be a La Caridad, near Nacozari, Mexico (1982 completion);73 year of surprises in the metal markets. There will be con­ 20,000 tpy electric furnace in the Sohar area, Sultanate of tinued expansion of mineral resources in developing coun­ Oman; 19 revamped Tennant Creek smelter4 -changeover tries, even though some projects viewed with enthusiasm from the top-blown rotary converter to Peirce-Smith con­ earlier have slowed down.I.66 In China,2 the Dexing project verter (late 1980 start-up); the 120,000 tpy flash smelter at (copper) and the Jinchuan mine (copper-nickel, reputed to Pirdop, Bulgaria; the 110,000 tpy flash furnace with hearth be as large as Sudbury, Ontario) have also slowed down. electrodes in the Philippines; the 65,000 tpy Mitsubishi There were no announcements of new copper, nickel, or plant50 for TexasGulf in Timmins, Ontario (mid-1981 lead smelters, and two plants, the St. Joe electrothermic start-up). zinc plant in Monaca, Pennsylvania and the Anaconda cop­ Table I lists some of the major process metallurgical ad­ per smelter/refinery in Montana, closed down in the face of vances made during the 19708. We see this strong develop- Table I: Milestones In Nonferrous Process Metallurgy in the 19705 Plant or Process Company and Location Year First large scale pyrometallurgical process Falconbridge Dominicana, 1971 for nickel laterites Dominican Republic First nickel flash furnace outside Finland Western Mining Corp. Ltd., 1972 Kalgoorlie, Western Australia First direct converting of nickel sulfide in TBRC Inco Metals Company, 1973 Copper Cliff, Ontario, Canada First pressure nickel carbonyl plant Inco Metals Company, 1973 Copper Cliff, Ontario, Canada World's first commercial continuous smelting and Noranda Mines Limited, 1973 converting process· Noranda, Quebec, Canada First CONTIROD process for continuous rod production Metallurgie Hoboken-Overpelt, 1973 Olen, Belgium KIVCET smelting for lead concentrates USSR 1972-74 World's largest electric copper smelting furnace Inspiration Copper Co., 1974 Inspiration, Arizona Hecla Mining and El Paso 1975·· The first large scale use of Roast-Leach-Electrowin Natural Gas process in North America First North American Outokumpu flash smelter and Phelps Dodge Corp., 1977 largest flash smelter Hidalgo, New Mexico World's first primary copper smelter using top-blown Afton Mines Limited, 1978 rotary converter Kamloops, British Columbia, Canada First nickel flash furnace with slag cleaning section Western Mining Corp. Ltd. 1978 after uptake Kalgoorlie, Western Australia * The second commercial continuous smelting and converting process was commissioned by Mitsubishi in 1974 in Japan. "Closed down in 1977 due to depressed copper prices, recently purchased by Noranda Exploration Inc. 28 JOURNAL OF METALS· April, 1981 ment work continuing into the '80s to make pyrometallurgical lurgical data together with some costs are given in the paper. processes more continuous, to eliminate costly batch opera­ The application of top-blowing lances in copper smelting tions and crane / ladle transfer steps, to increase energy was discussed in another KHD paper by Chaudhuri,46 efficiency, and to improve potential for recovery of harmful while the Boliden TBRC plant treating lead dust was emissions and effluents. Some of these developments and described by Nystedt.47 Operating data for the plant, which changes were discussed by D.A. Temple in the 1979 Insti­ produces a lead bullion and a speiss in an environmentally tution of Mining and Metallurgy presidential address. 72 clean environment, were presented. W.G. Davenport examined innovations and future changes A good paper on the first full year of the Afton smelter in in copper smelting in an excellent paper, "Copper Smelting British Columbia was presented at the 109th AIME Confer­ to the Year 2000."18 Copper smelting and converting facilities ence in Las Vegas last year. 64 The TBRC at Afton is an installed in the last decade were tabulated. Projecting a 80 ton vessel under license from Dravo Corporation and slow long-term growth in copper demand, it was estimated Inco Metals Company. During 1979, the unit averaged 144 that this growth will need one to two new smelters and short tons/ d of concentrate producing 87 tpd blister copper. refineries per year at or near the mine sites until the turn The feed material is a mixture of three parts flotation con­ of the century. Most of these will be oxygen enriched, centrate (56.3% Cu, 4.3% Fe, 5.2% S, 17.2% Si02 ) and one autogenous, continuous, or flash units with Pierce-Smith part metallic concentrate (82.5% Cu, 7.8% Fe, 0.2% S, 3.1% or Hoboken converters as the predominant converting vessel. Si02) with burnt lime as a flux to produce a slag analyzing There will be increased scrap recycle, and small hydro­ 4.3% Cu, 16% Fe, 33% Si02 and 22% CaO. This slag is metallurgical plants on sulfides will be operated. cooled in beds and milled in the gravity circuit, giving a The current status of the new generation of copper smelting copper recovery of only 65%; slag tailings loss represent processes was provided at the "Copper Smelting Technology 0.9% of new copper. Copper is cast into 900 lb cakes. Conference," organized by the British Columbia Government Data for the most recent campaign indicated 80 heats in a in Vancouver, November 5-6, 1980.3 Papers were given on campaign of 50 days. Total concentrate smelted was 7,540 the Noranda, Inco, Outokumpu, and Mitsubishi processes. tons (56% Cu). Brick consumption averaged 55 Ib/ton of KHD's new Con top process was presented and "sprinkle copper while tonnage oxygen and natural gas consumption smelting" testwork by Dravo at Phelps Dodge's Morenci averaged 12,100 and 4,200 SCF /ton of copper respectively. smelter was mentioned. Papers at the conference will be A magnetite coating is applied four to eight times per cam­ published3 and should be referred to for more details. paign by smelting in-situ a high grade magnetite concentrate. A mathematical model for flash smelting copper concen­ Evidently, U.S. smelters are postponing any decisions on 55 smelter retrofits by flash or continuous smelting until the trates has been described by Rvotti. The paper con­ feasibility of sprinkle smelting has been determined. While tains only limited results and a more extensive discussion is awaited. This approach coupled with the interesting work by the reverberatory furnace seemed to be re-emerging like the 56 mythical Phoenix, with oxygen burners, 51 oxygen enrich­ Jorgensen and co-workers at the CSIRO, Melbourne, ment,48 and prospects of a smelting shaft adaptation, 52 Victoria, Australia form a solid basis for optimizing and sprinkle smelting, in which a wide angle flash smelting burn­ improving control in flash smelting units. In the latest of a er is mounted on the furnace roof, 53 may offer the best hope series of studies,56.49 Jorgensen shows that the predominant of capitalizing on the assets of an existing plant. The Amax heat transfer mechanism in suspension smelting is conduc­ "dead" roast-blast furnace smelting process78 has been tion from the' flowing gas. Convection and radiation play developed to the point of commercialization. little part. The temperature of the injected particles is determined by the temperature of the surrounding gas rather Current developments in lead, zinc, and tin metallurgy than the presence of neighboring radiating bodies. It was ,are discussed in the Lead-Zinc-Tin '80 symposium volume suggested that fuel combustion concurrent with smelting now published by TMS-AIME. 6 The volume includes re­ may speed up attainment of ignition temperatures. views by Wright,7 Broadhead,8 Kellogg,9 Davey,1O Floyd,ll A new suspension smelting burner which gives a more 12 I and Willis. Several new processes· are described, including even distribution of concentrate has been patented by 13 14 the QSL Process for lead, a two-step process involving Outokumpu.7o The burner employs a ring of air jets in a oxidizing smelting (electric furnace) and slag cleaning for horizontal plane to spray the feed uniformly over a wider treating complex Pb-Cu-Zn materials at Hoboken, and the angle than previously. Adding the fuel to the flash furnace matte fuming 15 process for metal recovery from sulfide in different ways is also proposed. 71 The addition of coal to materials containing both copper and tin. Another process, the Mitsubishi concentrate smelting lances has been de­ the QS process, has also been proposed for continuous pro­ scribed by Suzuki (paper in reference 3.) The wet coal 67 duction of Bessemer matte from nickel concentrates. (3-4% of concentrate) is mixed with concentrate, dried, The 1979 CIM Conference of Metallurgists in Sudbury, and then fed into the smelting furnace. Apart from replacing Ontario provided delegates an opportunity to visit the large more expensive fuel oil, coal addition reduced refractory metallurgical operations in the area.