The Solvay process results in soda ash (predominantly sodium carbonate (Na 2 CO 3)) from brine (as a source of sodium chloride (NaCl)) and from limestone (as a source of calcium carbonate (CaCO 3)). The overall process is: 2 NaCl + CaCO 3 → Na 2 CO 3 + CaCl 2. The actual implementation of this global, overall reaction is intricate.