PURPOSE: To obtain a high-grade refined zinc mineral, by adding SO2 or a sulfite to mineral pulp containing a zinc mineral and iron sulfide minerals, further adding copper sulfate to the pulp after mixed with air, and then subjecting the treated pulp to zinc froth floatation.

CONSTITUTION: After SO2 of a sulfite is added to mineral pulp containing a zinc mineral and iron sulfide minerals, the pulp is adjusted at an alkaline pH lelve and mixed with air. By this treatment, the surface of iron sulfide mineral particles is rapidly oxidized and converted into 9 state inactive to a conventional anionic collector, while the floatability of the zinc mineral is improved. Consequently, the zinc mineral can be easily separated from the iron sulfide minerals. Thereafter, copper sulfate is added to the pulp before, after or during aeration. After addition of the copper sulfate and after the aeration, a collector is added to the pulp. Zinc is then separated from the pulp by a froth floatation process.