Soda ash, also known as sodium silicate, is an inorganic substance with the chemical formula Na₂SiO₃. Its aqueous solution is called water glass, and it comes in colorless, greenish, or brown solids or thick liquids. It is widely used in foundry, papermaking, sand casting, remolding, paper tube and box adhesive, construction, carbon black, subway construction, gold and silver foil lamination, ceramics, alkali for silicate sol, and can also be customized into various liquid sodium silicate products according to customer needs.