Sodium Silicate

Abstract

Sodium Silicate is a colourless compound of oxides of sodium and silica. It has a range of chemical formula varying in sodium oxide (Na2O) and silicon dioxide or silica (SiO2) contents or ratios. It is soluble in water and it is prepared by reacting silica sand and sodium carbonate at a high temperature ranging from 1200 to 1400OC. Aqueous solution of sodium silicate is called water glass. Sodium silicates are produced in the form of a variety of compounds ranging from Na2O.4SiO2 to 2Na2O.SiO2 by properly proportioning the reactants. Sodium silicates varying in ratio from Na2O.1.6SiO2 to Na2O.4SiO2 are known as colloidal silicates. These are sold as 20% to 50% aqueous solutions called water glass.