Sodium Sulfite, Anhydrous, 98% NSF
Sodium Sulfite, Anhydrous is an inorganic compound supplied as a free-flowing granular crystal, white to pale yellow in color, odorless, and readily soluble in water. It is a versatile reducing agent valued across industrial processes for its ability to scavenge oxygen, neutralize oxidizing agents, and act as a sulfonating agent. Its granular, free-flowing form makes it easy to dose, handle, and dissolve into solution.
Product Specifications
| Chemical Name | Sodium Sulfite, Anhydrous |
| Chemical Formula | Na2SO3 |
| CAS Number | 7757-83-7 |
| Molecular Weight | 126.04 g/mol |
| Sodium Sulfite (Na2SO3) | 97.0 – 100.0 % |
| Alkalinity (as Na2CO3) | 0.0 – 0.5 % |
| Sodium Sulfate (Na2SO4) | 0.0 – 2.5 % |
| Chlorides (Cl) | 0.0 – 0.02 % |
| Heavy Metals (as Pb) | 0.0 – 20 ppm |
| Iron (Fe) | 0.0 – 15 ppm |
| Water Insolubles | 0.0 – 100 ppm |
| pH (1% Solution) | 9.7 – 10.3 |
| Appearance | White to Pale Yellow |
| Physical State | Solid, Free-Flowing Granular Crystal |
| Relative Density | 2.63 |
| Bulk Density | ≈ 95 lb/ft³ |
| pH (5% Solution) | ≈ 10.1 |
| Solubility in Water | 17% at 10°C; 28% at 33.3°C |
| Decomposition Temperature | 900°C |
| Shelf Life | Nominally 36 months when properly stored in original packaging |
| Storage Conditions | Store in a cool, dry, well-ventilated indoor environment. Keep away from acids and oxidizing agents. |
Applications and Benefits:
- Used as a pulping agent in chemimechanical, chemithermomechanical, and sulphite pulp production.
- Removes dissolved oxygen from steam boiler water systems.
- Removes excess chlorine from wastewater treatment processes.
- Functions as a solubilizing agent in vegetable tanning.
- Acts as a sulfonating agent in chemical manufacturing.
- Serves as a reducing agent in polymerization and surfactant production.
- Used as a reducing agent for dyes in textile processing.
- Reduces chrome and other metals in industrial applications.
- Acts as a preservative and antioxidant in photographic developer solutions.
- Free-flowing granular form allows easy handling, dosing, and dissolution.
Caution:
Not classified as hazardous under the Globally Harmonized System (GHS) and not regulated for transport by the US DOT. Reacts with acids to release sulfur dioxide (SO₂), a toxic and irritating gas. Incompatible with oxidizing agents and may generate strong exothermic reactions. May cause severe allergic reactions in sulfite-sensitive individuals. Avoid skin and eye contact and inhalation of dust. For NSF applications, the maximum usage level is 22 mg/L. For ozone reduction, use approximately 215 mg/L sodium sulfite per 100 mg/L ozone. Residual sulfite levels shall not exceed 100 ppm in finished water. Store in a cool, dry, well-ventilated area away from acids and oxidizers. Refer to the Safety Data Sheet (SDS) before use.