硫酸锌中性浸出液净化除钴

Purification and Removal of Cobalt from Neutral Zinc Sulfate Leaching Solution

以模拟脱除铜镉后的中性浸出液为原料液,在50~90℃的温度范围内研究了温度、时间、Cu^(2+)、Sb^(3+)对锌粉置换除钴的影响,并采用锌片电极在上述溶液中进行了开路电位的测试和阻抗研究。结果表明,金属锌置换除钴离子因其析出过电位较高而受到抑制,加入Cu^(2+)和Sb^(3+)对Co^(2+)的置换都具有活化作用。Cu^(2+)活化速度快,但是除钴效果不稳定;Sb^(3+)活化时除钴速度仍然较慢,但是置换出来的钴能够稳定存在;当使用Cu^(2+)、Sb^(3+)联合活化时,钴的脱除速度更快、脱除效果更加稳定。电化学测试结果显示,Cu^(2+)能活化H+在金属锌上的析出,Sb^(3+)会延缓活化H+在金属锌上的析出。电化学阻抗研究发现,50℃时,Sb^(3+)对锌置换除Co^(2+)的阻抗具有轻微的降低作用,而Cu^(2+)对锌置换除Co^(2+)的阻抗具有显著的降低作用,当联合使用Cu^(2+)+Sb^(3+)时,锌置换除Co^(2+)的阻抗大幅度下降。

The effects of temperature,time,Cu^(2+)and Sb^(3+)on cobalt removal from simulated neutral leaching solution after removal of copper and cadmium by zinc powder replacement were studied in the temperature range of 50~90℃.The open circuit potential and impedance of zinc electrode were measured in the above solution.The experimental results show that the removal of cobalt ions by metal zinc replacement is inhibited due to the high precipitation over potential,and the addition of Cu^(2+)and Sb^(3+)has an activation effect on the replacement of Co^(2+).Cu^(2+)has a fast activation rate,but unstable cobalt removal effect.The cobalt removal speed is still slow during Sb^(3+)activation,but the replaced cobalt can exist stably.When Cu^(2+)and Sb^(3+)are used as activator,the removal rate of cobalt is faster and the effect is more stable.The results of electrochemical open-circuit potential test show that Cu^(2+)can activate H+precipitation on metal zinc,while Sb^(3+)can delay H+precipitation.It is found that Sb^(3+)has a slight decreasing effect on the impedance of Co^(2+)removal by zinc replacement at 50℃,while Cu^(2+)has a significant decreasing effect on the impedance of Co^(2+)removal by zinc replacement.When Cu^(2+)and Sb^(3+)are used together,the impedance of Co^(2+)removal by zinc substitution drops significantly.