湿法炼锌净化渣—钴镍渣选择性溶出研究

【作者】 王松森；

【导师】 李元高；

【作者基本信息】 中南大学 ， 物理化学， 2008， 硕士

【摘要】 针对湿法炼锌净化渣-钴镍渣的处理问题，本文对该渣的选择性溶出过程进行研究，可为工业上钴镍渣的溶出工艺与综合利用提供依据。实验研究得出主要结论如下：1．钴镍渣颗粒为包裹型结构。内部是未反应的单质锌，外层是置换反应析出的单质钴、镍；堆积一段时间后，部分锌、钴、镍被空气中的氧气所氧化生成氧化膜，包裹在颗粒的最表层。2．采用选择性溶出处理钴镍渣，控制过程pH≥3．5，终点pH≥4．0，不仅锌的溶出率很高（溶出率为95％左右），而且还能有效地将锌与钴镍分离（钴、镍的溶出率均低于10％），因此选择性溶出适用于钴镍渣的处理：3．在常温条件下，硫酸选择性溶出钴镍渣放出氢气的反应是准一级反应，表观反应速率常数k^*=0．5617 min^-1；4．钻镍渣溶出过程中，应用钻电极在线监测追踪Co²⁺浓度变化。实验研究表明，钴电极应用为指示电极的条件是保持溶液体系pH≤2．0；钴镍渣溶出反应开始一段时间后，钴电极指示的电极电势逐渐上升，表明Co²⁺浓度不断增加，这符合渣中氧化钴不断被H⁺溶出生成Co²⁺的事实，因此，在钴镍渣溶出中钴电极可定性指示Co²⁺浓度的变化情况。更多还原

【Abstract】 The selective acid leaching of cobalt and nickel residue generated in the process of ZnSO₄ purification is studied in this paper, which will provide a fundamental basis for the industrial leaching and utilization of cobalt and nickel residue. The main conclusions are as follows:1. The particulate of cobalt and nickel residue is determined to be surrounded structure. Metal zinc was in the core, and cobalt or nickel generated by displacement reaction was covered outside. After stacking the residue for some time, partial Zn, Co and Ni were oxidized by the oxygen in the air. As a result, a layer of oxidation film was formed and surrounded at the surface of the particulate;2. The selective acid leaching was introduced to dispose the cobalt and nickel residue at the condition of pH≥3.5 during the leaching process and pH≥4.0 at the end of the reaction. The experiments showed that leaching rate of zinc was 95% approximately, the Co and Ni less than 10%, so Co and Ni were enriched in the solid phase, and were separated from the zinc effectively. Therefore, the selective acid leaching is suitable for the cobalt and nickel residue disposal;3. At the room temperature, the selective acid leaching of cobalt and nickel residue is the first order reaction, and the constant rate k^* was determined to be 0.5617 min^-1;4. The investigations indicate that when cobalt electrode is used to indicate the concentration of Co²⁺, the pH of solution system must be lower than 2.0. The application of cobalt electrode to leaching experiments of cobalt and nickel residue at the pH of 2.0 showed that, after leaching reaction for a little while, the electrode potential indicated by cobalt electrode increased gradually, which suggested that the concentration of Co²⁺ was increasing continuously, which was just consistent with the fact that cobalt and nickel residue was continuously dissolved into cobalt ion. Therefore, cobalt electrode could be used to qualitatively indicate the cobalt ion changes during the acid leaching process of cobalt and nickel residue.更多还原