There are two processes for preparing water glass that are common this day. The first one is by reaction in liquid phase while the next one is by reaction in solid phase. However, alkaline and quartz sand are the same raw materials used in the two processes.
1. Process with reaction in liquid phase: Caustic soda, quartz sand and water are mixed in a mixing tank, and then the mixture is fed into a reactor, where steam is introduced. The reactant is liquid water glass with its module lower than 3. The reaction is as following: nSiO₂+2NaOH Na₂O•nSiO₂+H₂O
2. Process with reaction in solid phase (thermal process) The feed materials in this process are sodium carbonate and quartz sand, or sodium sulfate and quartz sand. The feed materials are heated in a reflection furnace. The reaction is as following: Na₂CO₃ +XSiO₂ → (Na₂O)•(SiO₂)X + CO₂ 4Na₂SO₄ +2C +4SiO₂→ 4Na₂SiO₃ +4SO₂ +2CO₂ The water glass produced by this thermal process can have modules depending on requirements for different applications.