Abstract:The solubility of magnesium sulfate in sulphuric acid solution was determined by equilibrium method in the temperature from T=(263.15 to 298.15)K.The results show that the solubility of magnesium sulfate decreases with the decreases of temperature or the increases of sulfuric acid concentration.The solubility data was correlated by Apelblat equation,empirical equation and (CNIBS)/Redlich-Kister equation,and (CNIBS)/Redlich-Kister equation has the best correlation effect,the average relative deviation is 0.41%, and the root mean square deviation is less than 3×10^-4. The changes of entropy(ΔSd)、enthalpy(ΔHd) and Gibbs free energy (ΔGd) of the dissolving process were obtained by modified vant-Hoof equation.The results show that the process of magnesium sulfateSdissolving was a spontaneous process of endothermicSand entropy-increasing and enthalpy change was the main factor affecting the dissolution process. The experimental results can provide data support for the research of magnesium sulfate removal technology by low temperature crystallization from the waste electrolyte of zinc hydrometallurgy.