Sodium disilicate

Sodium disilicate (CAS 13870-28-5) is an inorganic sodium silicate salt, commercially known under trade names such as SKS 6, Na-SKS 6, and Pyramid G 82. It carries no assigned E-code and is distinct from standard waterglass solutions by its defined crystalline stoichiometry, giving it predictable alkalinity and ion-exchange behaviour.

In detergent and cleaning formulations, sodium disilicate acts as a builder by sequestering calcium and magnesium ions while maintaining an alkaline pH that saponifies fats. In water treatment, it functions as a corrosion inhibitor by forming a protective silicate film on metal pipe surfaces, and in paper and textile processing it stabilises peroxide bleaching baths through pH buffering.

Sodium disilicate is supplied under REACH registration and is available in granular and powder grades suited to dry-blend formulations. Procurement teams should confirm grade specification against intended application, as particle size and moisture content affect dissolution rate and handling. Standard packaging includes 25 kg bags and bulk containers.