含氰贫液酸化产物中铜元素回收工艺研究

Research on Processes of Copper Recovery from Product in Acidified Barren Cyanide Solution

金精矿焙烧—氰化系统含氰贫液闭路循环需要定期开路部分贫液,贫液中的Cu元素具有一定的回收价值,本文在含氰贫液酸化法处理工艺基础上探索含氰贫液中Cu元素回收工艺的可行性。酸化处理后CN-挥发率为95.42%,铜沉淀率为97.82%。酸化后贫液固液分离所得酸化沉淀含铜22.77%～35.01%,采用焙烧—酸浸—萃取工艺回收铜,最佳实验条件如下：焙烧温度为640℃,液固比为5∶1,H2SO4质量浓度为5%,酸浸时间为3 h,此时可获得铜浸出率为92.27%～95.00%。以20%Lix984作为萃取剂,调节浸出液p H=2.3,有机相和水相相比为1∶1,萃取时间为3～5 min时,单级铜萃取率为98.96%;酸化后贫液固液分离所得液体平均铜浓度为72.89 mg/L,以硫化法深度沉淀铜,当Na2S用量为0.4～0.6 g/L,沉淀时间为1 h时,铜沉淀率为92.21%～99.09%。

In the system of gold concentrate roasting-cyanide ,the closed-circuit of barren solution containing cyanide need to be opened periodically,the copper in which has some recovery value.The feasibility of recovering copper from barren solution containing cyanide is investigated on the basis of acidification process. After the acidification the evaporation rate of cyanide ion is 95.42% and the precipitation rate of copper is 97.82%.There is 22.77%435.01% of copper in the acid sedimentation separated from acidified barren liquid.The copper can be reclaimed by a roasting-acid leaching-extraction technique, and the best experiment conditions are as follows：roasting temperature is 640 ℃, Liquid-solid ratio is 5：1, the concentration of H2SO4 is 5%, acid leaching time is 3 hours, and the copper leaching rate is up to 92.27%-95.00%.If 20% Lix984 is used as extraction agent, pH value of leaching solution is 2.3, organic and aqueous phase ratio （O/A） is 1：1, one stage copper extraction rate is 98.96% after 3-5 min extraction.The copper concentration in the solution separated from acidified barren liquid is 72.89 mg/L, sulfurized method is used in the copper deposit, if Na2S is 0.4 -0.6 g/L,the copper sedimentation rate is up to 92.21%-99.09% after one hour.