Sodium Bicarbonate (Technical) - India

Brief Overview
Sodium bicarbonate, a chemical molecule having the molecular formula NaHCO3, is commonly referred to as baking soda. It is readily soluble in water or mineral springs and has a white, crystalline or powdery appearance. Natural sources of sodium bicarbonate include the minerals thermokalite and nahcolite. Amphoteric substances, such as sodium bicarbonate, react with bases or acids. Sodium acetate may be produced by reacting it with acetic acid. Additionally, it produces carbonates through reactions with base chemicals like sodium hydroxide. At a temperature higher than 149°C, sodium bicarbonate will break down into sodium carbonate, a stable chemical, with the production of carbon dioxide and water as byproducts.
Manufacturing Process
Sodium bicarbonate may be made using the Solvay method. This procedure was initially developed in the 1860s by Ernest Solvay, who reacted sodium chloride with ammonia and carbon dioxide in water. This procedure yields sodium bicarbonate, which can be changed into soda ash (Na2CO3) or washing soda (Na2CO3.10H2O). This is how the production process looks like:
1. Manufacturing Sodium Bicarbonate
Sodium chloride reacts with carbon dioxide and ammonia in water to produce this reaction. In this procedure, the carbon dioxide is obtained from calcium carbonate, and the ammonia is separated from ammonium chloride using the calcium oxide byproduct. Dry ice is another source of carbon dioxide. The reaction is
NaCl(aq) + NH3(aq) + CO2(s) + H2O → NH4Cl(aq) + NaHCO3(s)
2. Extracting Sodium Bicarbonate
Step 1's reaction yields sodium bicarbonate and ammonium chloride as products. Both of these compounds are soluble at room temperature. However, ammonium chloride is more soluble than sodium bicarbonate at temperatures below room temperature, which facilitates the crystal's extraction from the solution. Reacting calcium hydroxide with ammonium chloride is another way to separate sodium bicarbonate from ammonium chloride. This procedure yields calcium chloride in the liquid phase, water vapor, and ammonia gas.