In 1861 Ernest Solvay (1832-1922, Belgium) made sodium carbonate and calcium chloride from table salt, limestone, and ammonia. This method is called Solvay Ammonia Soda Process Method.
CaCO₃ =heat= CaO + CO₂↑
CaO + H₂O = Ca(OH)₂
2NH₄Cl + Ca(OH)₂ === 2NH₃↑ + CaCl₂ + 2H₂O
NaCl + NH₃ + CO₂+ H₂O=== NaHCO₃↓+ NH₄Cl
2NaHCO₃ =heat= Na₂CO₃ + CO₂↑ + H₂O
In 1933 Dr. Hou Debang (1890-1974, China) improved the Ammonia Soda Process in 1933, introducing carbon dioxide into the process of soda production, so that ammonium chloride can be produced at the same time of soda production.
This method utilizes ammonia gas thoroughly rather than as a circulating substance, reducing the process difficulty, simplifies the manufacturing process and utilizing the previously unused chlorine element, thus improving the efficiency of soda production. This method is therefore called Hou's Process for Soda Production.
NH3 + H2O + CO2 = NH4HCO3
NH4HCO3 + NaCL = NH4CL + NaHCO3↓
2NaHCO3 =heat= Na2CO 3+ CO2↑+ H2O
At present, most of China's soda ash production enterprises adopt the Hou's Process, which has a significant cost advantage compared with the foreign enterprises that still adopt the Ammonia Soda Process. The invention of Hou's Process for Soda Production enables China's soda ash enterprises to occupy an important position in the world.
