砷化氢析出电势的探讨

来源期刊：中国有色金属学报2000年第1期

论文作者：仇勇海 唐仁衡 陈白珍

文章页码：101 - 104

关键词：砷化氢；析出电势；铜电解液

Key words：arsine; evolution potential; copper electrolyte

摘    要：据热力学参数，计算得到砷酸、亚砷酸、单质砷析出砷化氢的标准平衡电势值分别为0.144 V， 0.005V，-0.238 V。在铜电解液净化工序中，砷酸优先于亚砷酸析出砷化氢，当阴极电势足够负时，三者共同放电析出砷化氢。计算结果与实测结果基本吻合，均表明砷化氢析出的标准平衡电势值正于-0.608 V。在铜净液工序中，采用控制阴极电势脱铜脱砷电积法，能有效抑制砷化氢的析出。

Abstract: The standard equilibrium potentials of evolving AsH₃ from arsenic acid, arsenious acid and element arsenic are thermodynamically calculated as 0.144V, 0.005V, -0.238 V respectively. In the processing of the purification of copper electrolyte, arsenic acid prior to arsenious acid evolves AsH₃. When cathodic potential is negative enough, arsenic acid, arsenious acid and element arsenic co-discharge and AsH₃ is evolved. The results of thermodynamical calculation are basically concordance with the measured results. The standard equilibrium potential of AsH₃ evolution is absolutely more positive than -0.608V. In the processing of the purification of copper electrolyte, the separation of copper and arsenic by electrowinning of controlling cathodic potential can prevent AsH₃ from evolving effectively.