Sodium sulfide

Sodium sulfide (CAS 1313-82-2), also known as disodium sulfide, is an inorganic sulfur compound supplied primarily in hydrated flake form. It functions as a reducing and precipitating agent across several heavy industrial processes. The compound is in particular demand for leather processing, textile dyeing, and metals recovery. In leather tanning, it is the primary unhairing agent used to break down keratin bonds in hides during the beamhouse stage.

This chemical directly affects throughput and hide quality in the tanning process. Textile manufacturers use it as a reducing agent to solubilize sulfur dyes, enabling deep, wash-fast coloration on cotton and cellulosic fibers. In mining and hydrometallurgy, it precipitates heavy metal ions from process streams and leachates. This supports both metals recovery and effluent compliance for industrial facilities and large scale mining operations.

Paper pulp operations and water treatment facilities apply it for sulfide precipitation and pH adjustment. It is particularly effective in high-alkalinity process environments where precise chemical reactions are required. The product is commercially supplied as yellow to brick-red hydrated flakes, typically at 60% purity. This form usually contains approximately 30 to 40 percent water content to maintain stability during transport.

Technical grade is the standard market form, with purity commonly specified at 60% Na2S minimum. Anhydrous and higher-purity grades exist for specialty applications but are less common in bulk industrial trade.