Potassium Silicate vs. Sodium Silicate

Potassium Silicate (K2SiO3) glass is a colorless super-cooled melt of Potassium Carbonate and pure Silica Sand. It is slightly hygroscopic, but remains free flowing if stored in original unopened drum. Potassium Silicate (K2SiO3) solutions are prepared by dissolving Potassium Silicate (K2SiO3) glass in hot water. By varying the silica to Potassium Oxide (K2O) ratio, products of definite but widely different properties are produced.

Although Potassium Silicate has properties and uses similar to Sodium Silicate, but certain differences offer advantages in many uses, forming a basis for selecting Potassium Silicate in place of Sodium Silicate.

Solubility: Potassium Silicate is more soluble than Sodium Silicate of equal levels of alkalinity, making blends with Potassium Silicate more life-cycle stable, more rinsable, and offers the potential for higher concentration formulations.

Potassium Silicate glass dissolves more rapidly than Sodium Silicate glass of equal molar silica-to alkali ratio. Potassium Silicate glass can be dissolved in atmospheric dissolver, whereas pressure dissolver are generally used for Sodium Silicate glass.

Temperature Resistance:

Potassium Silicates offer higher temperature resistance for insulation applications, up to 100oF or 50oC higher than sodium silicates. This also applies to inorganic coating temperature stability as well, such as inorganic zinc coatings.

Low Efflorescence

Sodium Silicates tend to react with atmospheric Carbon Dioxide to form carbonates and become progressively less water-soluble. Potassium Silicate films are less likely than Sodium Silicate to develop a carbonate bloom or white efflorescent coat of alkali carbonate.

Lower Tack

Potassium Silicate solutions are not as sticky or tacky as Sodium Silicate solutions and are therefore easier to handle and use.