氯化钴密闭电积工艺优化与生产实践

Process optimization and production practice of cobalt chloride closed electrowinning

针对密闭电解槽钴电积槽压高、电流分布不均、电解卸板出槽时溶液喷溅、氯气逸出等问题,对工艺进行了优化改进,系统研究了工艺参数对钴电积的影响,并结合生产实际,对电解系统进行了技术改造。结果表明最佳工艺条件为:氯化钴溶液油含量≤3 mg/L、电积过程酸度控制在0.04~0.06 mol/L、电流密度<500 A/m^2、温度55~70℃、电解后液配4.5mol/L盐酸调节酸度后再返回萃取系统;对电解槽阴阳极导电棒采用钛包铜导电棒代替原铜导电棒,增加内部排液装置等优化改造,通过增加自动控酸系统、排液泵等对电积系统进行完善,可保证电流效率≥70%,槽压<2.7V,生产操作环境中氯气浓度0.5mg/L。三年的运行实践证明,经过工艺优化和设备改进后的密闭电解槽适合氯化钴萃取—电积工艺,技术指标先进,且工艺运行稳定、操作环境得到有效改善;与优化改进前相比,电流效率提高了约3.7%,直流电耗降低了660kW·h/tCo,总电耗降低了810kW·h/tCo,可有效降低生产成本,提高经济效益和社会效益。

Aiming at the problems such as high cell voltage,uneven current distribution,solution splashing and chlorine gas escaping from the closed electrolytic cell,the process was optimized and improved.The influence of process parameters on cobalt electrowinning was systematically studied.Combined with the production practice,the electrolytic system was revamped.The results showed that the optimum technological conditions were as follows:the content of cobalt chloride solution oil was less than 3 mg/L,the acidity of electrowinning process was controlled at 0.04-0.06 mol/L,the current density was less than 500 A/m^2,the temperature was 55-70℃,the liquid preparation after electrolysis was4.5 mol/L and hydrochloric acid was used to adjust the acidity before returning to the extraction system.The titanium clad copper conducting rod was used to replace the original copper conducting rod.The electrowinning system is improved by adding automatic acid control system and discharge pump,which can ensure the current efficiency≥70%,cell pressure<2.7 V,and chlorine concentration in the production and operation environment<0.5 mg/L.The three-year operation practice shows that the closed electrolytic cell after process optimization and equipment improvement is suitable for the combined process of cobalt chloride extraction electrowinning,with advanced technical indicators,stable process operation and effective improvement of operating environment;compared with that before optimization and improvement,the current efficiency is increased by about 3.7%,the DC power consumption is reduced by 660 kW·h/tCoand the total power consumption is reduced by 810 kW·h/tCo,which can effectively reduce the production cost and improve the economic and social benefits.