Technical specifications of sulfate on single water chemical formula ZnSO4.H2O Appearance Soft powder Maximum water insoluble substance (w / w ٪) 1 Minimum zinc (w / w%) 33 Maximum lead (w / w%) 30 ppm Maximum copper (w / w%) 1000 ppm Maximum magnesium (w / w%) 5000 ppm Maximum iron (w / w%) 5000 ppm At least PH 4 Maximum cadmium (w / w%) 25 ppm Maximum arsenic (w / w%) 50 ppm packing 25 kg layered bags and moisture resistant