德兴铜矿辉钼矿精矿的选择性电氧化浸出与分离过程

摘要

针对德兴铜矿高铜钼精矿特性，研究开发一种选择性电氧化浸出新工艺。结果表明，辉钼矿的电氧化浸出受电解液pH值的影响显著。采用Na2CO3-NH4HCO3缓冲溶液控制电解过程pH为9左右，可以实现辉钼矿的选择性电氧化高效浸出，钼、铼的浸出率分别为99.35%和99.79%，与非缓冲体系的电氧化过程相比，钼、铼的浸出率分别提高了23.86%和26.50%。在选择性电氧化过程中，黄铜矿基本上不能浸出而留在浸出渣中，电解渣中铜品位达到10.84%，回收率达到97.93%，可作为铜冶炼原料而回收。采用 N235为萃取剂，对电氧化浸出液中的钼、铼进行溶剂萃取，将溶液中HCl浓度调整为25.48 g/L时，可实现钼、铼的同时萃取，其萃取率分别为99.84%和95.19%；用17%的氨水反萃负载有机相，有机相中钼、铼的反萃率分别为99.89%和99.54%。将反萃液pH调整为8，30℃下用D201树脂吸附1 h，钼、铼的吸附率分别为3.46%和92.18%，分离因子为169.56。%A novel technique of selective electric-oxidation leaching, solvent extraction and ion exchange adsorption was studied for the recovery of Dexing molybdenite concentrates. The results show that the electric-oxidation leaching of molybdenite is impacted evidently by pH value of electrolyte. When the pH of electric-oxidation process was adjusted by buffered solutions of sodium carbonate and ammonium acid carbonate to about 9, MoS2 and ReS2 could be selectively oxidized, the dissolution rates of molybdenite and rhenium are 99.35%and 99.79%, respectively. Compared with that of the unbuffered system, the dissolution rates of molybdenite and rhenium increase by 23.86%and 26.50%, respectively. In the process of selective electric-oxidation leaching, chalcopyrite would not be leached, the grade of copper in the residue is 10.84% with a recovery rate of 97.93%, and it can be used as copper smelting materials. The separation of molybdenum and rhenium in the electrolyte was studied by solvent extraction and D201 resin adsorption. Coextraction of molybdenum and rhenium is found when N235 was used as an extractant and the concentration of HCl was adjusted to 25.48 g/L, the extraction efficiencies of Mo(Ⅵ) and Re(Ⅶ) are 99.84% and 95.19%, respectively. The stripping of molybdenum and rhenium to aqueous phase was investigated using 17% ammonia liquor, the stripping efficiencies of Mo(Ⅵ) and Re(Ⅶ) are about 99.89% and 99.54%, respectively. After stripping, rhenium was separated from molybdenum using D201 resin under pH 8 at 30℃, the adsorption rates of rhenium and molybdenum are 92.18%, 3.46%, respectively, and the separating factor is 169.56.