what is ferrous sulphate used for

{"title":"Premium Fes04 7h20 Purity Assured Iron Ii Sulphate 7 Hydrate For Pharmaceutical , Agricultural & Industrial Use","imgUrl":"https:\/\/img.silkroadsl.com\/nimg\/96\/f8\/187aa2bfc0cd641f53a643b2337a-200x200-1.jpg","attrs":{"Price":"USD85\/Ton","Brand Name":"AOXINCHENG","Model Number":"Ferrous Sulfate Heptahydrate Power","Minimum Order Quantity":"27 Ton","Delivery Time":"7-10 Days","Place of Origin":"ShanDong\uff0cChina","Payment Terms":"L\/C, T\/T","Supply Ability":"20000Ton\/Year","Packaging Details":"Customized Packaging","Product Name":"Ferrous Sulfate Heptahydrate Power","Ferrous Sulfate(FeSO4)":"99.0% To 100.5% Or Not Less Than 92% Or 99.9%","Chloride (Cl)":"\u22640.005%","Sulfur(S)":"\u226511.5%","Lead (Pb)":"Not More Than 0.001% To 0.002%","Cadmium (Cd)":"Not More Than 0.001% To 0.003%","Arsenic (As)":"Not More Than 0.0002% To 0.005%"}}