Metathesis Reaction : By reacting sodium carbonate with calcium hydroxide, the reaction yields sodium hydroxide and calcium carbonate. Since sodium hydroxide is soluble while calcium carbonate is not, by doing filtration, calcium carbonate can be easily removed to obtain a crude solution of sodium hydroxide. This solution is then purified, processed and standardized for industrial consumption.
Chloralkali Process : With the electrolysis of sodium chloride solution, solid sodium hydroxide is manufactured and obtained with the evaporation of water. Chlorine gas is also produced as a main by-product. Electrolysis occurs through three main types of cells, mainly mercury cell, diaphragm cell and membrane cell