3. Chemical Process Industries

Leblanc process — was used from 1792, by using salt, sulfuric acid, limestone, and coal. In 1861, Solvay process was introduced. By 1900, 90% of sodium carbonate was produced by the Solvay process, and the last Leblanc process plant closed in the early 1920s.

Solvay process uses limestone (\(\ce{CaCO3}\)), coal / coke (C) / natural gas, salt (\(\ce{NaCl}\)) and air as the raw materials and uses ammonia as a cyclic reagent.

\[\ce{CaCO3} + \ce{C} + \ce{O2} + 2 \ce{NaCl} \rightarrow \ce{Na2CO3} + \ce{CO2} + \ce{CaCl2}\]