Editing Sodium silicate (section)

==Production==
Solutions of sodium silicates can be produced by treating a mixture of [[silica]] (usually as [[quartz sand]]), [[caustic soda]], and water, with hot steam in a [[chemical reactor|reactor]]. The overall reaction is
: 2''x'' NaOH + {{chem|Si|O|2}} → {{chem|(|Na|2|O|)|''x''}}·{{chem|SiO|2}} + ''x'' {{chem|H|2|O}}

Sodium silicates can also be obtained by dissolving [[silicon dioxide|silica]] {{chem|Si|O|2}} (whose [[melting point]] is 1713&nbsp;°C) in molten [[sodium carbonate]] (that melts with decomposition at 851&nbsp;°C):<ref name = "Greenwood">{{Greenwood&Earnshaw}}</ref>
: ''x'' {{chem|Na|2|CO|3}} + {{chem|SiO|2}} → {{chem|(|Na|2|O|)|''x''}}·{{chem|SiO|2}} + ''x'' {{chem|CO|2}}
The material can be obtained also from [[sodium sulfate]] (melting point 884&nbsp;°C) with [[carbon]] as a reducing agent:
: 2''x'' {{chem|Na|2|SO|4}} + C + 2 {{chem|SiO|2}} → 2 {{chem|(|Na|2|O|)|''x''}}·{{chem|Si|O|2}} + 2 {{chem|SO|2}} + {{chem|CO|2}}

In 1990, 4 million [[ton]]s of alkali metal silicates were produced.<ref name=Ullmann/>

=== Ferrosilicon ===
{{Further|Ferrosilicon#Hydrogen production}}
Sodium silicate may be produced as a part of [[hydrogen production]] by dissolving ferrosilicon in an [[Aqueous solution|aqueous]] [[sodium hydroxide]] (NaOH·H<sub>2</sub>O) solution:<ref>{{Cite journal |last1=Brack |first1=Paul |last2=Dann |first2=Sandie E. |last3=Wijayantha |first3=K. G. Upul |last4=Adcock |first4=Paul |last5=Foster |first5=Simon |date=November 2015 |title=An old solution to a new problem? Hydrogen generation by the reaction of ferrosilicon with aqueous sodium hydroxide solutions |journal=Energy Science & Engineering |language=en |volume=3 |issue=6 |pages=535–540 |doi=10.1002/ese3.94|s2cid=54929253 |doi-access=free |bibcode=2015EneSE...3..535B }}</ref>

: 2NaOH + Si + H<sub>2</sub>O → Na<sub>2</sub>SiO<sub>3</sub> + 2H<sub>2</sub>

=== Bayer process ===
Though unprofitable, Na<sub>2</sub>SiO<sub>3</sub> is a byproduct of [[Bayer process]] which is often converted to [[calcium silicate]] (Ca<sub>2</sub>SiO<sub>4</sub>).