Method for preparing zinc-sulfur mineral depressor

A method for preparing a zinc-sulfur mineral depressor comprises the following steps that firstly, phosphoric acid, hydrochloric acid and water are mixed according to the mass ratio of 1-3: 1-2: 10-15 to obtain a solution 1; then sodium benzoate is added to the solution 1 according to the mass ratio of 1-2: 5-15, and the sodium benzoate and the solution 1 are stirred to be dissolved to obtain a solution 2; then sulfate or sulfite dissolved in water is added to the solution 2 according to the mass ratio of 1-2: 3-8, the temperature of the solution 2 is controlled to range from 60 DEG C to 70 DEG C, the stirring reaction is kept for 3-5 hours to obtain a solution 3, the solution 3 is subjected to suction filtration to obtain crystal dope, finally the crystal dope is dried at the temperature ranging from 80 DEG C to 85 DEG C, and the zinc-sulfur mineral depressors are obtained. The method is low in agent consumption, and can restrain zinc-sulfur minerals, and high-quality lead concentrate can be obtained.