Sodium Dithionite

Textile Industry: Primarily used for vat dyeing reduction and for stripping unwanted color from fabrics
Pulp and Paper: Employed in the bleaching of mechanical pulp and the de-inking of recycled paper.
Water Treatment: Used to reduce hexavalent chromium to trivalent chromium in industrial wastewater.

Sodium Hydrosulfite, "Hydro".

CAS: 7775-14-6
EC: 231-890-0
Sectors: Textiles, Leather & Paper, Water & Wastewater Treatment

Sodium Dithionite (CAS 7775-14-6), also known as Sodium Hydrosulfite, is a powerful reducing agent in white crystalline powder form that scavenges oxygen, and it is used for vat dyeing, color stripping, pulp and paper bleaching, de-inking, and hexavalent chromium reduction in wastewater. It is highly reactive and valued for its oxygen-scavenging capabilities.

This Technical Grade chemical is indispensable for stripping color and bleaching heat-sensitive materials. It is unstable in the presence of air and moisture, requiring specialized stabilization for industrial use.

In chemical processing, it acts as a primary reagent for vat dyeing and heavy metal recovery. Its rapid reaction rate makes it a preferred choice for high-speed industrial bleaching lines.

Typical Properties

Molecular formula	H₂O₄S₂.2Na
Molecular weight	174.11 g/mol
Appearance	White solid
Form	Powder/Solid
Color	White
Odor	None or slight scent of sulfur dioxide
Melting point	166-168 °C
Boiling point	1390°C
Density	2.19 g/cm³
Water solubility	250 g/L (20 °C)
Flash point	>100°C
pH	5.5-8.5 (50g/l, H2O, 20°C)
GHS signal word	Danger · Flammable, Irritant / harmful
HS code	28311010
Grades available	Technical Grade

Typical literature values for identification; lot-specific results are stated on the certificate of analysis (COA) and the safety data sheet (SDS) that accompany every delivery.

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