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Hydrometallurgical Process for Copper Recovery from Sulfide Ores.
Haskett-PR; Elges-CH III
U S Pat 3 961 942 1976 Jun; :
(Continuation in part of U.S. Pat. Appl. 413,408) Copper is extracted from concentrates of any sulfu?gzore such as chalcopyrite by heating with sufficient aqueous naoh preferably at least 20 wt pct concentration in a pressure vessel with oxygen at 80-200 psig pressure and 60 deg-120 deg c to satisfy the reaction: 4cufes2 + 1702 + 24naoh -> 4na2cu(oh)4 + 2fe2o3 + 8na2so4 + 4h2o, and allow about 0.5-3 H for completion of the reaction before lowering the pressure, cooling, and filtering out the fe2o3. Only sufficient naoh should be used to produce 10 g/l cu in solution. Most of the fe2o3 forms a protective inner lining on the vessel walls. In four applications of the process to sulfide concentrates containing 27-56 pct cu, 82-99 pct of the cu was dissolved. Its recovery could be effected by dehydration-precipitation or by reduction. This process avoids any air pollution by so2. The naoh could be regenerated by the le blanc treatment of na2so4.
U.S. Pat. 3,961,942; June 8, 1976; Chem. Abstr. 84:P63,143d