... ZnSO4:98%,99%Min 4)Form:White crystal powder,granular Zinc Sulfate Heptahydrate MedicineGradeTianjin Xinxin Chemical Factory is the largest manufacture ... (30,000Tons/Year),Calcium Hypochlorite (30,000Tons/Year),Zinc Chloride (10,000Tons/Year), in China.With 17years of experience ... to produce medicine.C.Have little heavy metal. Lead(pb)cadmium(Cd),chromium(Cr),arsenic(As)mercury(Hg) etc infaust elements ...