(昆明理工大學 冶金與能源工程學院，昆明 650093)
摘 要: 為了研究濕法煉鋅涉及的四元體系MgSO4-ZnSO4-H2SO4-H2O的固液相平衡及其溶液物化性質，采用等溫溶解平衡法，分析了-15~100 ℃下硫酸鎂在該體系飽和時的固液相平衡關系，測定了硫酸鎂的溶解度，并繪制了相應的溶解度曲線。結果表明：結晶MgSO4·nH2O (n=1, 6, 7)存在的溫度范圍較廣，平衡固相的晶型轉變對硫酸鎂溶解度的影響顯著。當平衡固相以MgSO4·7H2O或MgSO4·6H2O形式存在時，硫酸鎂溶解度隨溫度升高而增大；當平衡固相以MgSO4·H2O形式存在時，硫酸鎂溶解度隨溫度升高而減小。此外，增大硫酸濃度會抑制硫酸鎂的溶解，但可降低溶液體系的冰點。XRD分析結果顯示，該體系在-10 ℃下的平衡固相為MgSO4·7H2O和ZnSO4·7H2O，在40 ℃和65 ℃下的平衡固相為MgSO4·6H2O和ZnSO4·6H2O，在90 ℃下的平衡固相為MgSO4·H2O和ZnSO4·H2O。
關鍵字: 濕法煉鋅；硫酸鎂；四元體系；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
