... industry,it is used to make ferric salt,ink iron oxide red and indigo-blue, as mordant, tanning, water purification, ... , it is for fertilizer, weedicide, pesticide treating wheat smut etc. Ferrous sulphate monohydrate Usage: It is feed additive used as supplement ... is necessary for poultry growth, also used as making iron oxide red, granule material is good fertilizer, which can effectively improve ...