Sodium Sulfate Anhydrous

About This Product

Sodium sulfate anhydrous, Na2SO4 with CAS number 7757-82-6, is supplied as a free-flowing white powder or granule, freely soluble in water and giving a neutral solution. It is produced both as a natural mineral and as a by-product of numerous chemical processes. It is unusual among high-volume chemicals in being valued largely for what it does not do. It is neutral, non-hygroscopic, non-reactive and cheap, so in powder detergents it serves as a filler and flow aid that occupies volume, keeps the powder free-running and carries the active ingredients without interfering with them. In textile dyeing it has a genuine chemical function known as exhaustion. Reactive and direct dyes and cellulose fibres both carry negative charge in the dyebath and therefore repel each other, so much of the dye stays in solution. Adding sodium sulfate raises the ionic strength, screening that repulsion so the dye is driven onto the fibre, which both deepens the shade and reduces the dye left in the effluent. In glass manufacture it acts as a fining agent, removing bubbles and scum from the melt. It is used in powder detergents, textile dyeing, glass manufacture, paper pulping, and as a laboratory drying agent. Bio Green Chem supplies sodium sulfate to specification on assay, moisture, water-insoluble matter, chloride, iron, calcium and pH.