Ferric ion leaching of chalcopyrites from different localities
- PDF / 771,895 Bytes
- 7 Pages / 583.28 x 792 pts Page_size
- 10 Downloads / 253 Views
I.
INTRODUCTION
B E C A U S E of the costs associated with meeting increasingly stringent hygiene and environmental regulations, copper producers continue to seek alternatives to conventional smelting technology. Leaching processes based on ferric chloride, 1'2'3 cupric chloride-ferric chloride, 4,5,6 or ferric sulfate7'8'9 remain as strong contenders among the new technologies, and several of these options are currently being examined at the pilot or demonstration plant scale. Most interest has centered on chalcopyrite (CuFeS2) concentrates because this compound is by far the most abundant of the copper minerals on a global scale. Because of the dual importance of chalcopyrite and ferric ion leaching, many studies have been reported on the experimental factors affecting chalcopyrite leaching and on the mechanism of its dissolution (Discussion presented in References 10, 11). These previous investigations have clarified much of the chemical leaching behavior, and have offered some sound thoughts on how the leaching occurs, although the precise mechanism of chalcopyrite attack is still not fully understood. Of the areas of chalcopyrite leaching still requiring clarification, one of the most persistent and controversial is whether or not chalcopyrites from different localities leach at different rates. Some authors have reported that all chalcopyrites leach at essentially identical rates regardless of their origin, but other authors have noted substantial, order of magnitude, differences in the leaching behavior. The whole aspect of the importance of the source of the chalcopyrite emerged clearly several years ago when Wyckoff12postulated two types of chalcopyrite, Cu2§ and Cul+Fe3§ to explain his observed variations in bacterial leaching rates. Although subsequent Mossbauer studies by many workers t3 showed that all chalcopyrites were essentially identical, the question of different chalcopyrites leaching at different rates still remained. Dutrizac et al t4 observed an order of magnitude difference in the chemical leaching rate between natural (Temagami, Ontario) chalcopyrite and synthetic CuFeS2. These authors attributed the difference to the much greater surface area of the sintered synthetic CuFeS2 ~5 but felt that effects caused by minor amounts of sulfide impurities in the natural material might also be important. Later work 15 showed that major concentrations of J.E. DUTRIZAC is Head, Metallurgical Chemistry Section, Mineral Sciences Laboratories, CANMET, Energy, Mines and Resources Canada, 555 Booth Street, Ottawa, Ont., Canada KIA 0G1. Manuscript submitted January 25, 1982. METALLURGICAL TRANSACTIONS B
sulfide impurities were necessary to alter materially the chemical leaching rate of chalcopyrite, and hence that the area effect was predominantly responsible for the difference in behavior between the natural and synthetic chalcopyrites. Paynter16reviewed the influence of locality on the chemical leaching rate of chalcopyrite, and noted that the reactivity of different chalcopyrite concentrates seemed to v
Data Loading...
