Caustic Soda Specifications
Caustic soda has a chemical formula of NaOH. It is used to make soaps, rayom, paper, explosives, dyestuffs, and petroleum products. It is also used in processing cotton fabric, laundering and bleaching, metal cleaning and processing, oxide coating, electroplating, and electrolytic extracting. It is commonly present in commercial drain and oven cleaners. Caustic soda common name is sodium hydroxide and usually comes in a white solid appearance. It is an inorganic alkali salt, hygroscopic in nature, and is soluble in water and polar solvents. It has a slippery feel and also absorbs carbon dioxide in the atmosphere to form sodium carbonate. Caustic soda is mainly used in textiles in the form of caustic soda flakes or pearls.
The Manufacturing Process
- Heating : The first step of caustic soda manufacturing is to heat the solid alkaline mineral which consisted of hydrated double salts of sodium carbonate and calcium carbonate with a 1:1 molar ratio until the water of the hydrated salts is removed and will produce sodium carbonate and calcium oxide
- Mixing : The second step of caustic soda manufacturing is to mix the calcium oxide with water and the mixture will causticize the sodium carbonate then generate an aqueous mixture of suspended calcium carbonate in a caustic soda solution
- Separation : The suspension formed from the mixing process is separated to obtain the caustic soda in a solution form called liquid caustic soda. To obtain the solid caustic soda, the liquid caustic soda is precipitated by lowering the temperature to the freezing point of liquid caustic soda
Caustic Soda Applications
Caustic soda applications are spread around many industries. It is used for pulp, aluminum, and sugar production. It is used as catalyst in production of biodiesel. It is used as a cleaning and disinfectant agent.
1. Food and Beverage : Having an E number from European Food Safety Authority (EFSA), caustic soda flakes uses is classified as an acidity regulator in the food industry with an E number of E524.
2. Soap and Detergent : Caustic soda uses in detergent industry as a strong alkali has an important role to trigger the saponification process for soaps and detergents manufacturing, particularly producing soaps and detergents which have solid forms.
3. Metal and Steel : The metal and steel industry used caustic soda as a cleaning agent to remove the excess or remaining water-insoluble substance which remain on the surface of the metal or steel
4. Paint, Ink and Coating : Similar to the metal and steel industry, the coating industry used caustic soda as a degreaser, which has an objective to polish the surface of the metal or steel from the excess water-insoluble substances.