碱式硫酸锌在湿法炼锌过程结晶热力学研究

对中国几家湿法炼锌厂净化阶段产生的结晶渣进行X射线衍射分析，确定了湿法炼锌过程产生的碱式硫酸锌的结构是ZnSO₄·3Zn（OH）₂·5H₂O，从而否定了是ZnSO₄·3Zn（OH）₂的传统观点，表明碱式硫酸锌的溶解度与水的活度有关。采用高温硫酸锌溶液中加入氧化锌粉末的方法制得与炼锌厂碱式硫酸锌结晶渣晶型一致的产物。同等硫酸锌浓度、pH条件下，碱式硫酸锌溶解度随着温度的升高而升高。研究表明，在锌质量浓度为168 g/L、pH为5.2的中性浸出液中，碱式硫酸锌析出温度为60.6 ℃±0.4 ℃，80 ℃降到40 ℃的析出量为4.4 g/L。

Study on crystallization thermodynamics for basic zinc sulfate in zinc hydrometallurgy

 Scales in the hydrometallurgical process of zinc from several zinc hydrometallurgical plants in China were analyzed by X-ray diffraction，showing that crystalline structure of basic zinc sulfate existed in the form of ZnSO₄·3Zn（OH）₂· 5H₂O，so as to deny traditional view of ZnSO₄·3Zn（OH）₂.Results indicated that the solubility of the basic zinc sulfate had re-lation to the water activity.The target crystallization of basic zinc sulfate was prepared by adding zinc oxide powder into high temperature zinc sulfate solution with crystal structure consistent with scales.At same concentration of zinc sulfate and pH，solubilities of ZnSO₄·3Zn（OH）₂·5H₂O increased with temperature increasing.Research results showed the precipitation temperature of basic zinc sulfate in neutral leaching solution of zinc hydrometallurgy, with zinc mass concentration of 168 g/L and pH= 5.2，was 60.6 ℃±0.4 ℃，and precipitates quantity in the process of decreasing temperature from 80 ℃ to 40 ℃ was 4.4 g/L.