... 20% 2)package,25kg/bag 3)Usage, additives,fertilizer,water scavenging agent iron sulfate heptahydrateMolecular Formula: FeSO4·(X) H20 (X=1 ... is offwhite powder ,used for the manufacture of iron salts, ink, iron oxide red and indigo-blue; as mordant ,tanning ... agent,water scavenging agent,wood preservative,disinfectant and heliograph etc.as fertilizer ...