Chlorination of chalcopyrite concentrates
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I. INTRODUCTION AND LITERATURE REVIEW
SULFIDE ores and concentrates are still the major source of the primary production of basic metals such as Cu, Pb, Zn, etc. The pyro- and hydrometallurgical processing of these sulfides is responsible for environmental pollution due to SOx generation. Despite the technological progress, the SOx emissions remain a serious problem from an ecological point of view. The conversion of SO2 to H2SO4 is marginal because of the transportation cost and the state of the sulfuric acid market. Different methods had been proposed to avoid sulfur dioxide formation during the extraction of valuable metals from sulfides. Gaballah et al.[1] suggested the thermal treatment of complex sulfide ores under a controlled atmosphere (N2 and H2) at temperatures lower than or equal to 1000 8C. The proposed flow sheet permits the recovery of sulfur, galena, trace-element compounds, zinc, and a residue rich in copper. Habashi[2] suggested that the hydrometallurgical route offers the possibility of obtaining sulfur at a moderate temperature and pressure, thus solving the problem of sulfide treatment. Several studies have been devoted to the chlorination process as an alternative to recovering the copper from its sulfides at relatively low temperatures. Donaldson and Kershner[3] studied the chlorination of CuFeS2 by chlorine between 25 8C and 300 8C in a horizontal experimental set. They observed that the intensive chlorination of CuFeS2, generating the copper and iron chlorides, started at 150 8C and that almost full chlorination was achieved at about 250 8C. Landsberg et al.[4] employed thermogravimetric analysis (TGA) to investigate the chlorination of CuFeS2 by Cl2 1 Ar from 25 8C to 300 8C. A value of apparent activation energy (Ea) of about 35.6 kJ/mol was pointed out by these authors for temperatures between 25 8C and 100 8C. They N. KANARI, Researcher, and I. GABALLAH, Senior Researcher, are with the Laboratoire Environnement et Mineralurgie, associated with the Centre National de la Recherche Scientifique, Mineral Processing and Environmental Engineering Team, INPL-ENSG, LEM, 54501 Vandoeuvre Cedex, France. E. ALLAIN, Scientist, is with the Center of Pyrometallurgy, Department of Metallurgical Engineering, University of Missouri Rolla, Rolla, MO 65409-1460. N. MENAD, Researcher, is with the Department of Chemical and Metallurgical Engineering, Division of Process Metallurgy, Lulea University of Technology, Se 97187, Lulea, Sweden. Manuscript submitted November 6, 1998. METALLURGICAL AND MATERIALS TRANSACTIONS B
observed the formation of a product layer at about 200 8C and underlined that the slowest step of the chlorination reaction is the diffusion of reactive gases through this layer. They concluded that the chlorination reaction became exothermic at 300 8C, thus facilitating the chlorination of sulfur, iron, and copper-bearing compounds. Finally, the authors suggested that the chlorination rate depends on the rate of volatilization of the reaction products. Olsen et al.[5] developed a process fo
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