Co-Cu-Zn-Pb-Ni-Cl-H_2O体系的热力学分析

Thermodynamic Analysis of Co-Cu-Zn-Pb-Ni-Cl-H_2O System

根据配位化学热力学平衡原理,通过热力学平衡计算绘制出了298.15 K时钴电解液体系中5种金属离子(Co2+、Cu2+、Zn2+、Pb2+、Ni2+)及其配离子的c-lg c[Cl]T图和c-pH图。热力学计算显示,pH为2.5时钴电解液中铅、锌主要以配合阴离子形式存在,钴、铜、镍主要以阳离子形式存在,可以采用阴离子树脂交换法将微量铅、锌与钴、铜、镍有效分离。对所绘的热力学平衡图分析表明,高浓度氯离子有利于与金属形成配合离子,提高铅锌的配合阴离子含量,有利于阴离子树脂交换除铅、锌。

c-lg cT and c-pH diagrams for complex ions（Co2＋、Cu2＋、Zn2＋、Pb2＋、Ni2＋） at 298.15 K were drawn respectively based on the thermodynamic equilibrium principle of complex chemistry.The results show that in cobalt electrolysis solution,the occurrence states of cobalt,copper and nickel are free ions and complex cations at pH 2.5,while the lead and zinc exist as complex anions which can be removed by anion exchange resin.In addition,the amount of complex anions of lead and zinc are increased with the improving of Cl-concentration,which is beneficial to the removing process of lead and zinc.