Zinc sulfate Heptahydrate for paint,printing ink,rubber,cable,medicines,electronics,papermaking,enamel,match,cosmetic and others Zinc sulfate HeptahydrateSpecification: superior quality fist grade qualify gradeZn content≥% 22.0 21.0 20.0free acid content≤% 0.1 0.2 0.3Pb content≤% 0.002 0.005 0.01Cd content≤% 0.002 0.002 0.003As content≤% 0.002 0.005 0.007