Abstract: A production process of MgSO₄·7H₂O by hot melt crystallization method was introduced，with flotation tailings from a potash magnesium sulphate fertilizer workshop of a sulfate-type saline Mine in Northwest of China as raw material.The process overcame the defects of the conventional flotation process，shortened the process flow，reduced the production cost，and improved the grade of magnesium sulfate heptahydrate products.Various affecting factors were also discussed，and the optimal parameters and conditions were determined.Qualified product of MgSO₄·7H₂O was obtained which met the requirement of National Standard（first grade）.

Key words: potassium magnesium fertilizer, magnesium sulfate heptahydrate, hot melt crystallization, salt lake resource