Ferrous chloride dihydrate is widely used in wastewater treatment processes as a coagulant to remove phosphates and other contaminants. It helps in reducing the levels of heavy metals and suspended solids in industrial and municipal wastewater.

In the chemical industry, it serves as a catalyst in various organic synthesis reactions, particularly in the production of chlorinated compounds. It is also utilized in the manufacturing of ferric chloride, which is another important chemical in water treatment and electronics.

Additionally, it finds application in the textile industry as a mordant, helping to fix dyes onto fabrics, ensuring colorfastness. In the pharmaceutical sector, it is used as a reducing agent in the synthesis of certain drugs and as a source of iron in dietary supplements.

In metallurgy, ferrous chloride dihydrate is employed in the pickling of stainless steel and other metals to remove surface oxides and impurities, preparing them for further processing or coating.