Solvay process

The Solvay Process is a chemical process which uses ammonia to convert salt and calcium carbonate into sodium carbonate and calcium chloride.

1. Roast calcium carbonate (Limestone) to give calcium oxide and carbon dioxide:

   {{#Chem:CaCO3 = CaO + CO2 //roast}}

2. Bubble carbon dioxide through a mixture of aqueous ammonia and salt in water, giving ammonium chloride and sodium bicarbonate

   {{#Chem: NaCl + NH3 + H2O + CO2 = NaHCO3↓(s) + NH4Cl(aq)}}

3. Filter off the sodium bicarbonate
4. Recombine the calcium oxide with the aqueous ammonium chloride giving ammonia and calcium chloride.

   {{#Chem: 2NH4Cl(aq) + CaO = 2NH3 + CaCl2 +H2O}}