Lithium Polysilicate

Lithium polysilicate is an inorganic binder useful for coating, surface modification, and polymer reinforcement applications. Unlike polysilicates based on sodium or potassium ions, the lithium ions in lithium polysilicate permit a ratio of 4.8 of silica to lithium oxide. This is one of the highest ratios of silica in polysilicate products on the market.
Lithium polysilicate is typically used in concrete densifiers, where the silica reacts with available calcium hydroxide in the concrete to build density. Unlike other silicate products, the small size of the lithium ion allows for deeper penetration of silica into the concrete, increasing densifier effectivity. Lithium polysilicate is effective in this application at concentrations between 10% and 15%. Upon drying, the excess densifier will become dust that is easily removed without scrubbing or flushing.

Another common application for lithium polysilicate is as a binder for zinc-rich primers and coatings used for corrosion protection in industrial and marine environments. Here, the high ratio of lithium oxide to silica permits greater binding capacity for zinc, yielding films that provide excellent protection against corrosion and chemical attack. Lithium polysilicate may also be used in waterborne masonry paints to form films with good adhesion to masonry and cementitious substrates. It is also used in anticorrosive metal pretreatments to improve the adhesion of coatings applied. Lithium polysilicate has also been used as a safer replacement in formulations that use hexavalent chromium.