Borax is prepared from

Borax, also known as sodium tetraborate, is a significant sodium compound widely used in various industries. It is commercially prepared using sodium carbonate (washing soda) [1]. One common method involves the reaction of sodium carbonate with boric acid or by boiling the mineral colemanite (calcium borate) with a sodium carbonate solution. In this process, sodium carbonate reacts with the borate minerals to precipitate calcium carbonate while leaving sodium tetraborate (borax) in the solution, which is then crystallized [1]. Sodium carbonate itself is a versatile chemical used in glass, soap, and paper manufacturing, as well as for removing water hardness [1]. While other carbonates like calcium or magnesium carbonate exist in nature as limestone or dolomite, they are not the primary reagents for synthesizing borax. Therefore, sodium carbonate is the essential precursor for borax production.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Uses of washing soda > p. 32