炼铜烟灰碱浸脱砷的热力学及动力学

Thermodynamics and Kinetics of Alkaline Leaching of Arsenic in Copper Smelting Dust

基于热力学计算,绘制了常温(298K)条件下Me-S-H2O系(Me:Cu,Pb,Zn,As)Eh-pH图,并对pH=13～15时As2S3、CuS、Cu2S、PbS、ZnS热力学稳定区进行分析。结果表明,在碱浸体系中,砷与铜、铅、锌等有价金属的分离在热力学上是可行的。基于NaOH与(NaOH+Na2S)两种体系中砷的浸出行为研究,为提高铜烟灰碱浸脱砷效率,选择(NaOH+Na2S)浸出体系是适宜的。在该体系中,在303～363K范围内,铜烟灰中砷的浸出过程受内扩散控制,浸出动力学方程遵循未反应收缩核模型。

Eh-pH diagram of Me-S-HzO system （Me： Cu, Pb, Zn, As） at 298 K was plotted and the stable area of As2S3, CuS, Cu2S, PbS and ZnS was analyzed in the pH field of 13-15 based on thermodynamic calculation. The results show that separation of arsenic from copper, lead and zinc in alkaline leaching is feasible in terms of thermodynamics. The leaching behavior of arsenic in NaOFI and NaOH＋Na2S system was studied respectively and the results show that NaOH＋Na2S system is appropriate for the removal of arsenic by alkaline leaching. The dissolution of arsenic in this system under the temperature of 303-363 K is controlled by inner diffusion and its leaching kinetic equation follows the unreacted shrinking core model.