Sodium Sulfite Anhydrous (Sodium Sulfite), is an odorless white crystalline powder widely used as industrial reducing agent, food bleach and preservative, textile auxiliary and water treatment chemical. It features stable chemical properties and reliable reducibility for dozens of manufacturing sectors. Qingdao Tianya Chemical Co., Ltd ranks among China’s top manufacturers of Sodium Sulfite Anhydrous. We provide two professional grades of anhydrous sodium sulfite, including Food Grade Anhydrous Sodium Sulfite and Industrial Grade Anhydrous Sodium Sulfite. Different grades adopt targeted quality standards to meet food safety and industrial production requirements respectively.
Product information
| Product Name | Sodium Sulfite Anhydrous |
| Manufacturer | Qingdao Tianya Chemical Co., Ltd |
| CAS No | 7757-83-7 |
| HS Code | 28321000 |
| EINECS No | 231-821-4 |
| Synonyms | Sodium Sulfite, Sodium Sulphite, Sodium Sulphite Anhydrous |
| Molecular Formula | Na2SO3 |
| Molecular Weight | 126.04 |
| Melting Point | 500 °C |
| Density | 2.633 g/cm³ |
| Accurate Mass | 125.93600 |
Physical & Chemical Properties of Sodium Sulfite Anhydrous
| Appearance | White crystal powder, no peculiar odor |
| Solubility | Highly soluble in water; slightly soluble in ethanol; nearly insoluble in ether, liquid chlorine and liquid ammonia |
| Water Solubility Data | 0℃: 12.54g per 100ml water; Peak solubility at 33.4℃ (28% concentration); 80℃: 28.3g per 100ml water |
| Aqueous Solution Alkalinity | pH value ranges from 9.0 to 11.0 |
| Chemical Stability | Prone to oxidize into sodium sulfate when exposed to open air; decomposes into sodium sulfide under high temperature |
| Reaction Characteristics | 1. Acts as a strong reducing agent in general chemical reactions; 2. Reacts with sulfur dioxide to produce sodium bisulfite; 3. Reacts with strong acids to generate corresponding inorganic salts |
Applications of Sodium Sulfite Anhydrous
Laboratory & Analytical Chemistry
Used for trace element testing of tellurium and niobium, developing liquid preparation, and serving as a standard inorganic reducing reagent. It also acts as raw material for photosensitive resistance components in electronic production.
Textile, Printing & Dyeing Industry
- Stabilizer for artificial fiber production
- Bleaching auxiliary for woven fabrics and dyestuffs
- Cotton fabric boiling agent: prevents local fiber oxidation, retains fabric tensile strength and boosts fabric whiteness
- Reducing agent for dye synthesis and color fixing processes
Paper Manufacturing Field
Functions as an efficient lignin removal agent during pulp processing to improve paper brightness and pulp quality.
Photographic Industry
Classic photographic developer material for traditional film processing solutions.
Organic Chemical Synthesis
Critical reducing agent for producing m-Phenylenediamine, 2,5-dichloro intermediates, anthraquinone-1-sulfonic acid, 1-Aminoanthraquinone, sodium paramisan and other dye intermediates. It effectively stops semi-finished products from oxidation during synthesis reactions.
Electronic & Water Treatment
- Electronic industry: Raw material for photosensitive resistance parts
- Water treatment: Deoxidizer and purification chemical for electroplating wastewater and drinking water systems
Food Grade Anhydrous Sodium Sulfite (Bleach, Preservative, Antioxidant)
Approved as food additive with clear maximum usage limits calculated by residual SO₂ content:
- Preserves (candied fruits): Max dosage 2.0g/kg
- Glucose, liquid glucose, white sugar, rock sugar, maltose, hard candy, bamboo shoots, fresh mushrooms, canned mushrooms, grape & blackcurrant concentrated juice: Max dosage 0.60g/kg
- Residual control standard:
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- Bamboo shoots, mushroom cans, fruit cans, grape & blackcurrant juice concentrate: ≤0.05g/kg SO₂
- Potato starch: ≤0.03g/kg SO₂
- Biscuits, sugar, vermicelli: Below 0.1g/kg SO₂
- Liquid glucose: No more than 0.2g/kg SO₂
It suppresses oxidase activity in plant-based food, slowing browning and spoilage; also applied as reducing agent for dehydrated vegetable processing and pharmaceutical synthesis.
Other Multi-Scenario Usages
- Raw material to manufacture sulfite cellulose ester, sodium hyposulfite and fine pharmaceutical chemicals
- Fabric bleaching agent, antichlor, preservative and universal reducing agent across fine chemical sectors
- Standard lab reagent for sulfur dioxide gas preparation
Why Choose Qingdao Tianya Chemical as Your Anhydrous Sodium Sulfite Supplier
As a professional manufacturer & exporter of Sodium Sulfite Anhydrous, we deliver reliable products and full export service for global buyers.
Strict Factory Quality Control
- Independent production lines for industrial & food grade Sodium Sulfite Anhydrous
- Batch-by-batch lab testing, full COA provided for every shipment
- Stable purity 96%-98%, controlled impurities meeting global standards
Two Grades to Cover All Demands
- Industrial Grade: For textile printing, papermaking, water treatment, dye synthesis and lab reagents
- Food Grade: Compliant with international SO₂ residual limits for food preservation, sugar & canned food processing
Custom specs available per your local requirements.
All-in-One Support Service
- Free samples for quality test before bulk orders
- Professional technical guidance for your production application
- Fast quotation, full cargo tracking and 24h response for after-sales issues
Mature Global Export Experience
We have supplied Sodium Sulfite Anhydrous to 60+ countries, maintaining long-term cooperation with textile mills, water treatment plants and chemical distributors.
Tianya Chemical supplies stable, high-purity Sodium Sulfite Anhydrous in bulk orders for global wholesalers, factories and trading companies worldwide. Our team offers flexible packaging, full COA test reports and complete export documentation. Feel free to contact our sales team to place orders, request free samples or get latest bulk quotations.
FAQs
1. What is the difference between sodium sulfite anhydrous and sodium sulfite heptahydrate?
The key difference lies in water content. Sodium Sulfite Anhydrous (Na₂SO₃) contains no water molecules, while Sodium Sulfite Heptahydrate (Na₂SO₃·7H₂O) contains seven water molecules per formula unit. Sodium sulfite anhydrous is more stable than the crystalline form and less prone to oxidation, making it the preferred choice for most industrial and food applications.
2. What are the main grades of sodium sulfite you supply?
Tianya Chemical supplies two primary grades: Industrial Grade and Food Grade.
- Industrial Grade: Designed for textile printing, papermaking, water treatment, dye synthesis, and laboratory reagents.
- Food Grade: Complies with international SO₂ residual limits for food preservation, sugar processing, and canned food applications. Food grade undergoes more rigorous quality control to meet food safety regulations, with stricter limits on impurities like heavy metals.
3. How should sodium sulfite anhydrous be stored?
Sodium sulfite anhydrous should be stored in a cool, dry, and well-ventilated area, inside tightly sealed containers. It is sensitive to moisture and prone to oxidation into sodium sulfate when exposed to air. Keep away from acids, strong oxidizing agents, and combustible materials. When properly stored, the shelf life is typically 24 months.
4. Is sodium sulfite anhydrous a hazardous chemical for shipping?
Sodium sulfite anhydrous is generally classified as non-hazardous for most modes of transport. However, when shipped by air, it may be classified as Class 9 hazardous material under certain regulations. For sea freight, it is shipped in standard containers with proper moisture-proof packaging. We provide full export documentation and compliance support for all shipments.
5. What is the typical purity of your sodium sulfite anhydrous?
Our sodium sulfite anhydrous maintains stable purity between 96% and 98%, with controlled impurities meeting global standards. Every batch undergoes rigorous laboratory testing, and a complete Certificate of Analysis is provided for each shipment.
6. What is the pH value of sodium sulfite anhydrous aqueous solution?
The aqueous solution of sodium sulfite anhydrous is alkaline, with a pH value ranging from 9.0 to 11.0.
7. How does sodium sulfite anhydrous work as a water treatment chemical?
In water treatment, sodium sulfite anhydrous acts as an oxygen scavenger and deoxidizer. It removes dissolved oxygen from boiler feedwater and industrial water systems, effectively preventing corrosion. It is also used in electroplating wastewater treatment and drinking water purification systems.
