Abstract: Calcium and magnesium contents of one zinc sulphate plant′s zinc sulphate product were on the high side and its product′s main content was also very low，because zinc oxide ore，the raw material had high contents of calcium and magnesium，resulting in high content of calcium and magnesium in zinc sulphate solution during the sulfuric acid leaching process.Therefore，the product quality was affected.The removal of Ca²⁺ and Mg²⁺ from aqueus zinc sulphate solution with hydrofluoric acid precipitation process was experimentally studied and the production application was also made.Using hydrofluoric acid as precipitant at low temperature and high pH conditions，Ca²⁺ and Mg²⁺ could be removed effectively from the solution.Moreover，the accumulation of fluorine ions in the solution could also be controlled.Thus the product′s quality could be improved.

Key words: zinc sulphate, fluoride precipitation, calcium, magnesium