Sodium Dithionite Supplier South Africa

What Is Sodium Dithionite?

Sodium dithionite (sodium hydrosulphite) is a powerful reducing agent and reductive bleaching salt widely used in industries where oxidative bleaches such as hydrogen peroxide or chlorine would damage the substrate or produce unwanted side reactions. It is particularly valuable in the textile industry for reduction clearing and vat dyeing, and in the paper and pulp industry for brightening of mechanical pulp.

Textile and Industrial Bleaching

In vat dyeing, sodium dithionite is the standard reductant that converts insoluble oxidised vat dyes to their soluble leucoform, allowing them to substantively absorb into cellulosic fibres. After dyeing the leucoform is re-oxidised by air to regenerate the insoluble pigment permanently fixed within the fibre. For bleaching, sodium dithionite removes colour from natural fibres (wool, silk) and tannin stains from wood and paper without the fibre damage associated with oxidative bleaches.

Handling and Supply

Sodium dithionite is moisture-sensitive and reacts exothermically with water, generating sulphur dioxide gas; it should be stored in sealed containers in a cool, dry location away from ignition sources. Terracore Chemicals supplies technical-grade sodium dithionite (85–88% active) in 25 kg bags and drums for textile processors, paper mills, mineral processing plants, and specialty cleaning product manufacturers.