Sodium silicate is an inorganic sodium salt that contains the counterion silicate. Furthermore, it goes by the names Waterglass and Sodium metasilicate. Sodium silicate has the chemical formula (Na2O) xSiO2.

 

Sodium metasilicate is a flaked solid or powdered material. It breaks down in water to generate alkaline solutions. Also, it possesses a polymeric anion. It remains intact in neutral and alkaline solutions, but in acidic solutions, the hydrogen ions in the silicate ions will react to form silicic acids, which are likely to break down into hydrated silicon on the dioxide gel. When heated further, the water evaporates, leaving behind a hard translucent substance known as silica gel.

PROPERTIES

Sodium silicates are glassy-appearing crystalline substances. Moreover, Liquid glass and water glass are two common names for sodium silicate aqueous solutions.

Due to their water solubility, they produce alkaline solutions. Simply put, this chemical compound is soluble and stable in both neutral and alkaline solutions. In contrast, in an acidic medium, the ions of silicate and hydrogen combine to form silicic acid, which has a propensity to break down into hydrated silicon dioxide gel. After removing the water, the remaining product is silica gel, a hard, translucent substance.

Uses of Sodium silicate ((Na2O)x·SiO2)

  • In wastewater treatment facilities, sodium silicate is used as an alum coagulant as well as an iron flocculant.
  • It is used as a fixative in hand-dying.
  • It is used in ceramics.
  • It’s commonly used in food storage, homebrewing, and aquaculture.

Production of Sodium silicate

In a reactor, silica, water, and caustic soda can be treated with hot steam to create sodium silicate solution. The following is the response:

2x NaOH + SiO2 → (Na2O)x·SiO2 + x H2O

Sodium metasilicate can also be synthesized by dissolving silica SiO2 in molten sodium carbonate (Na2CO3) at 851 °C.

x Na2CO3 + SiO2 → (Na2O)x·SiO2 + CO2