(昆明理工大学 冶金与能源工程学院，昆明 650093)
摘 要: 为了研究湿法炼锌涉及的四元体系MgSO4-ZnSO4-H2SO4-H2O的固液相平衡及其溶液物化性质，采用等温溶解平衡法，分析了-15~100 ℃下硫酸镁在该体系饱和时的固液相平衡关系，测定了硫酸镁的溶解度，并绘制了相应的溶解度曲线。结果表明：结晶MgSO4·nH2O (n=1, 6, 7)存在的温度范围较广，平衡固相的晶型转变对硫酸镁溶解度的影响显著。当平衡固相以MgSO4·7H2O或MgSO4·6H2O形式存在时，硫酸镁溶解度随温度升高而增大；当平衡固相以MgSO4·H2O形式存在时，硫酸镁溶解度随温度升高而减小。此外，增大硫酸浓度会抑制硫酸镁的溶解，但可降低溶液体系的冰点。XRD分析结果显示，该体系在-10 ℃下的平衡固相为MgSO4·7H2O和ZnSO4·7H2O，在40 ℃和65 ℃下的平衡固相为MgSO4·6H2O和ZnSO4·6H2O，在90 ℃下的平衡固相为MgSO4·H2O和ZnSO4·H2O。
关键字: 湿法炼锌；硫酸镁；四元体系；固液相平衡；溶解度
（Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, China）
Abstract:In order to investigate phase equilibrium behavior of the quaternary MgSO4-ZnSO4-H2SO4-H2O system and provide the data of physical and chemical properties to zinc hydrometallurgy, the solid-liquid equilibrium of magnesium sulfate in the MgSO4-ZnSO4-H2SO4-H2O system was studied in the temperature range from -15 ℃ to 100 ℃ by isothermal equilibrium. The solubility of magnesium sulfate was measured and the corresponding solubility curves were pictured. The results reveal that MgSO4·nH2O (n=1, 6, 7) crystals exist in a wide temperature range, and the crystal transition of the equilibrium solid phase has a significant effect on the solubility of magnesium sulfate. In addition, the dissolution of magnesium sulfate is suppressed by increasing the H2SO4 concentration, but the freezing point of the solution can be lowered. The XRD patterns show that the crystalline compositions at -10 ℃ are MgSO4·7H2O and ZnSO4·7H2O, those at 40 ℃ and 65 ℃ are MgSO4·6H2O and ZnSO4·6H2O, and those at 90 ℃ are MgSO4·H2O and ZnSO4·H2O.
Key words: zinc hydrometallurgy; magnesium sulfate; quaternary system; solid-liquid equilibrium; solubility
