Sodium hexametaphosphate(SHMP) is a hexamer of composition (NaPO3)6. Sodium hexametaphosphate of commerce is typically a mixture of polymeric metaphosphates, of which the hexamer is one, and is usually the compound referred to by this name. It is more correctly termed sodium polymetaphosphate.
Sodium Hexameta Phosphate is a water soluble glass of Sodium Phosphate which is also known as Graham's Salt. Sodium Hexameta Phosphate has a property of "SEQUESTRATION" due to which it forms soluble complex ions with salts of Calcium, Magnesium, Zinc, Iron, etc., thus preventing deposition of their insoluble salts. By virtue of this property Sodium Hexameta Phosphate is an excellent water softner and used in wide applications.
Typical uses for Sodium Hexameta Phosphate are :
- It finds use in boiler water where it prevents deposition of Calcium and Magnesium salts on boiler tubes.
- In case of soaps, it not only prevents the precipitation of soap as Calcium salt (Calcium Soap) but actually dissolves such soap. It has therefore, found important function of removing Calcium Soap which otherwise encrusts the washed textiles.
- It is extensively used in process water, industrial water and cooling water for softening of water.
- It is also used as dispersant in paper industry, as deflocculating agent in petroleum industry and as coagulation agent in lather tanning.