Sodium sulphate ((text{Na}_{2}text{SO}_{4})) is a versatile inorganic compound found as a white crystalline solid or powder. It exists in several forms, most notably as anhydrous sodium sulphate (water-free) and the decahydrate Glauber's salt ((text{Na}_{2}text{SO}_{4}cdot 10text{H}_{2}text{O})). Key Properties Chemical Stability: It is highly stable and unreactive toward most oxidizing or reducing agents at normal temperatures.Solubility: Highly soluble in water, but its solubility is unusual, peaking at (32.38^{circ }text{C}) before becoming nearly independent of temperature.pH: It is a neutral salt, forming aqueous solutions with a pH of approximately 7.Safety: Generally regarded as non-toxic and non-hazardous, though dust can cause minor eye or respiratory irritation. Major Industrial Applications Detergents: Primarily used as a cost-effective filler in powdered laundry detergents to improve flowability and stability.Glass Manufacturing: Acts as a 'fining agent' to help remove small air bubbles from molten glass.Pulp and Paper: Essential in the Kraft process for paper pulping, where it helps break down wood fibres.Textiles: Used as a levelling agent in dyeing to ensure uniform absorption of dyes onto fabrics.Laboratory Use: The anhydrous form is widely used as an inert drying agent to remove traces of water from organic solvents. Forms and Sources Anhydrous ((text{Na}_{2}text{SO}_{4})): Occurs naturally as the mineral thenardite.Decahydrate ((text{Na}_{2}text{SO}_{4}cdot 10text{H}_{2}text{O})): Known as Glauber's salt or the mineral mirabilite; two-thirds of the world's production comes from this natural mineral.Synthetic: Often produced as a by-product of chemical processes, such as hydrochloric acid production. Pricing (India Estimates) Industrial grade sodium sulphate typically ranges between ₹4.50 and ₹20 per kg depending on purity and quantity. High-purity laboratory or food-grade variants can cost significantly more, often exceeding ₹300 per kg for specialized ACS or FCC grades.
