Also known as the Solvay Process.
An industrial method of making
sodium carbonate from ammonium carbonate and sodium chloride. When carbon
dioxide is passed into a nearly saturated solution of common salt containing
ammonia, ammonium carbonate is formed and this tends to pass into ammonium
hydrogencarbonate, which reacts with sodium chloride to form sodium
hydrogencarbonate and ammonium chloride. Sodium hydrogencarbonate is sparingly
soluble in a solution of sodium chloride or ammonium chloride, and mostly separates
out as a solid which may be filtered off.
2NH3 + H2O + CO2 ==> (NH4)2CO3
(NH4)2CO3 + H2O + CO2 ==> 2NH4HCO3
NaCl + NH4HCO3 <==> NaHCO3 + NH4CL
Sodium hydrogencarbonate is then heated to give sodium carbonate and carbon dioxide.
2NaHCO3 ==> Na2CO3 + CO2 + H2O
The ammonium chloride is heated with calcium oxide to regenerate the ammonia.
In 1881 Ernest Solvay was the first to successfully use this process. 1872 was the first time that is was used on a large scale.