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氨法浸出是基于目标金属与氨形成配合离子进入溶液,实现目标金属与部分杂质的分离,因此浸出过程具有选择性。对钴、铜与氨的配合机制及亚硫酸钠还原性能的影响因素进行了分析。结果表明:提高cNH3/cMe有利于形成稳定性高的钴、铜氨配合离子;降低cSO42-/cSO32-,提高体系pH可降低还原剂还原电位。实验过程采用加压氨浸工艺,在NH3-NH4+-H2O体系中浸出钴铜氧化矿中的钴和铜,研究了总氨浓度、氨铵比、液固比、浸出温度、还原剂用量对氧化矿中钴和铜浸出率的影响。结果表明,在总氨浓度7 mol.L-1、氨铵比2∶1、液固比6∶1、浸出温度100℃、还原剂亚硫酸钠用量为三价钴含量(摩尔比)4倍的最优条件下,钴浸出率可达到95.2%,铜浸出率可达到95.8%。浸出液后续处理工艺简单,氨及铵盐可实现闭路循环,对环境友好。
Ammonia leaching is based on the target metal and ammonia to form complex ions into the solution to achieve the separation of the target metal and some impurities, so the leaching process is selective. The coordination mechanism of cobalt, copper and ammonia and the influencing factors of sodium sulfite reduction performance were analyzed. The results showed that increasing cNH3 / cMe could promote the formation of cobalt and copper ammonia complex ions with high stability, reducing cSO42- / cSO32- and increasing the pH of the system could reduce the reduction potential of the reductant. In the experiment, pressurized ammonia leaching process was used to extract cobalt and copper from cobalt-copper oxide ore in NH3-NH4 + -H2O system. The effects of total ammonia concentration, ammonium ratio, liquid-solid ratio, leaching temperature, Effect of Cobalt and Copper Leaching Rates in Ore. The results showed that when the total ammonia concentration was 7 mol·L-1, ammonium-to-ammonia ratio was 2:1, the liquid-solid ratio was 6:1, the leaching temperature was 100 ℃ and the amount of sodium sulfite reducer was 4 times that of trivalent cobalt Excellent conditions, the cobalt leaching rate can reach 95.2%, copper leaching rate can reach 95.8%. Leaching solution follow-up process is simple, ammonia and ammonium salts can achieve closed-circuit, environmentally friendly.