What Does Ferrous Sulfate Mean?
Ferrous sulfate is an inorganic salt with the chemical formula FeSO4.xH2O. The hydrated ferrous sulfate is used for industrial applications and for the treatment of iron deficiency. It is also known as iron (II) sulfate. Ferrous sulfate is found in many states of hydration ranging from one molecule H2O to seven molecules H2O.
Ferrous sulfate has many uses. It primarily serves as a precursor to other iron compounds. It is also used as a reducing agent for the reduction of chromate in cement.
Corrosionpedia Explains Ferrous Sulfate
Ferrous sulfate is an iron compound containing iron (II) and sulfate. It is water-soluble; upon dissolving it forms a paramagnetic ion. When heating anhydrous ferrous sulfate, it decomposes and releases sulfur dioxide and white fumes of sulfur trioxide with a reddish-brown iron (III) oxide as follows:
2 FeSO4 --> Fe2O3 + SO2 + SO3
As a reducing agent, it reduces nitric acid to nitrogen oxide and chlorine to chloride:
6 FeSO4 + 3 H2SO4 + 2 HNO3 --> 3 Fe2(SO4)3 + 4 H2O + 2 NO
6 FeSO4 + 3 Cl2 --> 2 Fe2(SO4)3 + 2 FeCl3
When ferrous sulfate oxidizes, it forms a corrosive brown-yellow coating of basic ferric sulfate:
12 FeSO4 + 3 O2 --> 4 Fe2(SO4)3 + 2 Fe2O3
Ferrous sulfate has many uses. It is used to manufacture inks, to stain concrete and limestone, and for water purification and sewage treatment. When it is added to the cooling water flowing through the brass tubes of turbine condensers, it forms a corrosion-resistant protective coating.
Ferrous sulfate reduces the corrosion rate of copper-nickel in both polluted and unpolluted seawater.