Ferrous Sulfate

About This Product

Ferrous sulfate, iron(II) sulfate, is supplied chiefly as the heptahydrate, FeSO4.7H2O with CAS number 7782-63-0, or the monohydrate with CAS number 17375-41-6, as pale green to off-white crystals or granules. The divalent oxidation state is central to its function and also to its instability, since it oxidises in air to brown ferric compounds. That reducing power is what drives its largest application. Portland cement contains traces of hexavalent chromium from the raw materials and the kiln, and hexavalent chromium is a potent skin sensitiser responsible for chromate dermatitis in construction workers. Adding ferrous sulfate reduces it to trivalent chromium, which is not a sensitiser, and EU regulation has required the treatment since 2005. The additive has a shelf life because the ferrous iron itself slowly oxidises and loses activity, which is why treated cement carries a use-by date. It is also a coagulant in water treatment, an iron supplement in feed and nutrition, a moss killer in lawn products where it burns moss and greens grass simultaneously, and a reagent for treating chromate and cyanide wastes. It is used in cement chromate reduction, water and wastewater treatment, iron supplementation, moss control, and in pigment and chemical manufacture. Bio Green Chem supplies ferrous sulfate to specification on iron content, ferric iron, free acid, moisture, insolubles and heavy metals.