非洲某低品位氧化铜矿伴生钴的强化浸出和浸出动力学

Enhanced leaching and leaching kinetics of cobalt in low-grade copper ores of Africa

对非洲某低品位氧化铜矿伴生钴的强化浸出和浸出过程动力学进行了研究,探讨了浸出温度、硫酸加入量、液固比和还原剂焦亚硫酸钠加入量对钴浸出率的影响,从热力学角度探讨了伴生钴的还原浸出机理。结果表明,提高浸出温度、硫酸加入量、液固比和还原剂加入量均能提高伴生钴的浸出率,并加快钴的浸出速率;该氧化铜矿伴生钴的浸出过程受界面化学反应和固态产物层扩散混合控制,浸出过程表观活化能E_(a)=13.42 kJ/moL;动力学速率方程为1/3ln(1-x)+(1-x)-1/3-1=0.0025m^(0.8688)r^(0.1974)N^(1.0147)_(e)-13.42/RTt.

The leaching and leaching kinetics of Cobalt in low-grade copper ores of Africa were studied and the mechanism of reduction leaching of associated cobalt was discussed from the perspective of thermodynamics.The results show that increasing the amount of reducing agent,sulfuric acid,leaching temperature and liquid-solid ratio can improve the leaching rate of cobalt,and speedup the process of leaching.The leaching equilibrium of cobalt can be achieved in about 1 hour.The dissolution behavior of cobalt in low-grade copper ores coincides with the mixed kineticshrinking core model,which is based on the interface transfer and diffusion across the solid layers.The activation energy is determined to be 13.42 kJ/mol and the kinetic equation can be expressed as follows:1/3ln(1-x)+(1-x)-1/3-1=0.0025m^(0.8688)r^(0.1974)N^(1.0147)_(e)-13.42/RTt.It provides a theoretical basis for improving the leaching rate of associated cobalt in practical production.