湿法炼锌铁钒除铁工艺管路结晶的机理探讨

Mechanism Study on Crystallization in Pipeline during Iron Removal by Jarosite Method in Zinc Hydrometallurgy

通过对湿法炼锌过程所涉及的三元体系M_2SO_4-ZnSO_4-H_2O(M=K,Na,NH4)溶解度相图的比较研究,发现在上述三元体系中,在一般的冶炼工艺条件下,复盐(如(NH_4)_2SO_4·ZnSO_4·6H_2O(s)、Na_2SO_4·ZnSO_4·4H_2O(s)、K_2SO_4·ZnSO_4·6H_2O(s)远比单盐(如ZnSO_4·7H_2O(s)、Na_2SO_4(s)、K_2SO_4(s))要容易析出得多。这些复盐在溶液中的溶解度均随着温度的降低而降低,是管路结晶的主要诱因。溶解度较小的((NH_4)_2SO_4·ZnSO_4·6H_2O(s)生成是导致黄铵铁钒除铁过程管路易结晶堵塞的主因。

Based on comparative analysis on solubility phase diagrams of ternary systems M_2SO_4-ZnSO_4-H_2O（M=K,Na,NH4）concerned in zinc hydrometallurgical process,it is revealed that double salts（（NH_4）_2SO_4·ZnSO_4·6H_2O（s）,Na_2SO_4 ·ZnSO_4·4H_2O（s）,and K_2SO_4 ·ZnSO_4·6H_2O（s））are much easier to precipitate from electrolyte solutions than their single salts（NH_4）_2SO_4,Na_2SO_4,K_2SO_4,and ZnSO_4·6H_2O（s）.Drops of solubility of these salts（-hydrates）with decreasing temperature can cause scaling on wall of pipelines.Lower solubility of（（NH_4）_2SO_4·ZnSO_4·6H_2O（s） makes it easier to scale when ammonium jarosite substitutes potassium jarosite or sodium jarosite to remove iron in zinc hydrometallurgy.