Sodium sulfate or brine is key raw material for manufacturing both sodium carbonate and bicarbonate. By reacting the sodium sulfate with calcium carbonate, soda ash is produced this method is called LeBlanc process and when brine and ammonia are used as reactants the process is referred to solvay process.
Sodium carbonate is reacted with carbon dioxide and H2O to form sodium bicarbonate. Along with this the byproducts calcium sulfate and calcium chloride are generated.
A functions diagram explains the process, each block in the figure represent the operations involved in manufacturing for LeBlanc and Solvay process.