Sodium Sulfide Red Flake (Na₂S) 1313-82-2

Sodium Sulfide Red Flake is a reddish-brown crystalline flake with 60% Na₂S purity and a molecular weight of 78.04 g/mol. The red-brown color comes from trace iron impurities in the product. It is the most widely used and economical grade of sodium sulfide for leather dehairing and copper mining flotation applications.

Red flake sodium sulfide contains trace iron impurities that give it its reddish-brown color. Yellow flake is more refined with lower iron content and a lighter color. Both grades contain approximately 60% Na₂S. Red flake is the standard choice for leather processing and mining where the iron content does not affect performance. Yellow flake is preferred for textile dyeing and specialty applications where a cleaner color or lower iron content is required.

In leather processing, sodium sulfide red flake is used in the liming or unhairing process. It hydrolyzes the disulfide bonds in the keratin protein of animal hair and epidermis, breaking down the hair structure for easy removal. It is typically applied in a lime-sulfide bath, where the combination of sodium sulfide and calcium hydroxide swells the hide and dissolves the hair.

In copper mining, sodium sulfide red flake is used as a sulfidizing agent in froth flotation. It reacts with oxidized copper mineral surfaces to form a copper sulfide layer. This sulfidized surface then allows conventional collectors like xanthates to attach and float the copper minerals, significantly improving oxide copper recovery rates.

Sodium sulfide red flake is corrosive and requires careful handling. It releases toxic hydrogen sulfide gas when in contact with acids. It is hygroscopic and will absorb moisture from air. Store in a cool, dry, well-ventilated area in tightly sealed containers away from acids and moisture. Use appropriate PPE including chemical-resistant gloves, goggles, and respiratory protection when handling. Solutions should be kept alkaline to minimize H₂S release.