What Is Sodium Carbonate?
Sodium carbonate, a white, hygroscopic powder, is an alkaline metal carbonate with the chemical formula Na2CO3. Known as soda ash, disodium carbonate, and anhydrous sodium carbonate, it is also referred to as soda carbonate or soda.
Uses of Sodium Carbonate
As a versatile raw material, sodium carbonate is integral to producing various chemical products, including carbonates like magnesium carbonate and barium carbonate, amino acids such as glutamic acid, food ingredients like soy sauce, and baking soda (sodium bicarbonate). Its applications extend to glass manufacturing for flat glass and water glass, and in the textile industry for cleaning cotton yarns and wool. Furthermore, sodium carbonate is utilized in dye production, soap powders, as a desulfurizing agent, in pulp processing, and pharmaceuticals.
Properties of Sodium Carbonate
An odorless, white solid, sodium carbonate exhibits hygroscopic properties, with a molecular weight of 105.99, a specific gravity of 2.533, and a melting point of 851°C. It absorbs moisture gradually from the air and starts to lose CO2 at 400°C when heated, forming sodium bicarbonate (NaHCO3) upon CO2 absorption. A 1% aqueous solution has a pH of 11.3, showing alkalinity by ionizing and producing OH– ions. Sodium carbonate forms a 10-hydrate below 32°C, a 7-hydrate between 32°C and 35°C, and a 1-hydrate above 35°C, with the 10-hydrate known as washing soda potentially decomposing to 1-hydrate when exposed to air.
Other Information on Sodium Carbonate
How Sodium Carbonate Is Produced
Sodium carbonate is manufactured through various methods, including the ammonia soda (Solvay) method, the sodium chloride soda method, and the caustic soda carbonation method. The Solvay method, which has been used industrially for many years, uses sodium chloride (NaCl), ammonia (NH3), seawater, and limestone (CaCO3) as raw materials. The production process involves brine purification to remove calcium and magnesium salts, ammonia absorption to create ammonia brine, carbonation to produce and precipitate sodium carbonate, and solid-liquid separation and calcination to convert sodium bicarbonate to sodium carbonate. This process efficiently recycles ammonia and converts NH4Cl byproducts back to ammonia, showcasing an effective loop of resource utilization.