Caustic soda, also known as sodium hydroxide (NaOH), is a key product of Chlor-Alkali Plant, produced through the electrolysis of brine. It is an essential chemical compound used in various industrial processes. In Indonesia, it plays a crucial input in the country’s growing downstream industries, particularly in alumina and nickel extraction. It also serves an essential use in water treatment by stabilizing pH levels and neutralizing acidic impurities, ensuring a safe and clean water supply. Aside from its applications in metallurgy and environmental processes, caustic soda is also an important ingredient in textile production, pulp and paper manufacturing, as well as in the development of soaps and detergents.