Basic Information

Chinese Name: 硫酸钠
English Name: Sodium Sulfate
Chemical Formula：Na2SO4
Molecular Weight：142.04 g/mol (anhydrous); 322.20 g/mol (sodium sulfate decahydrate, Na2SO4⋅10H2O)
Appearance & Odor
Anhydrous form: White crystalline powder, odorless
Decahydrate form: Colorless transparent monoclinic crystals, odorless
Physical Constants
Boiling Point: 1429 °C (decomposes at high temperature)
Melting Point: 884 °C (anhydrous form)
Density: 2.68 g/cm³ (anhydrous, 20 °C); 1.46 g/cm³ (decahydrate, 20 °C)
Flash Point: Non-flammable
Solubility in Water: ~42.7 g/100 mL (20 °C, anhydrous); solubility decreases with temperature rise above 32.4 °C
CAS No.：7757-82-6

Solvent Properties

Solubility
Highly soluble in water, forming neutral aqueous solutions (pH≈7 at 25 °C).
Slightly soluble in glycerol; insoluble in ethanol, ether, benzene and most other organic solvents.
The decahydrate form will lose crystal water and turn into anhydrous sodium sulfate when heated to 32.4 °C.
Solvent Characteristics
As an ionic salt, its aqueous solution has good electrical conductivity and can be used as an electrolyte medium in electroplating and chemical analysis.
It has a significant salting-out effect—adding saturated sodium sulfate solution to the aqueous solution of organic substances can reduce the solubility of organic compounds and promote their precipitation and separation.
It can be used as a drying agent for some organic solutions (anhydrous form) due to its strong water absorption.

Main Applications

Chemical Manufacturing
A key raw material for producing sodium sulfide, sodium silicate, sodium carbonate and other inorganic chemicals.
Used in the manufacturing of synthetic detergents, acting as a builder to enhance decontamination performance and reduce surfactant dosage.
Textile & Paper Industry
Serves as a dyeing auxiliary in textile printing and dyeing: acts as a levelling agent and fixing agent for reactive dyes, improving dye uptake rate and color fastness of fabrics.
Applied in papermaking process as a cooking agent for pulp, helping to remove lignin and improve pulp quality.
Glass & Construction Industry
Added to glass formulations to reduce melting temperature of raw materials, lower production energy consumption, and improve the transparency and mechanical strength of glass products.
Used as a concrete admixture to adjust setting time and enhance frost resistance of concrete.
Other Fields
Pharmaceutical Industry: Used as a mild laxative (oral administration) and an osmotic diuretic in some formulations.
Food Industry: Approved as a food additive (E511), used as a processing aid, anti-caking agent and pH regulator in baked goods, dairy products and condiments.
Water Treatment: Applied in wastewater treatment to remove calcium and magnesium ions, and as a coagulant aid to improve sedimentation effect of suspended solids.

Safety

Hazard Classifications
Non-flammable, Non-explosive: No fire or explosion risk under normal storage and operation conditions.
Low Toxicity: Oral intake of large amounts may cause gastrointestinal discomfort (nausea, vomiting, diarrhea); long-term exposure to dust may cause mild irritation to respiratory tract and eyes.
Non-corrosive: Does not corrode metals, skin or common packaging materials.
Handling Precautions
Operate in a well-ventilated environment; wear dust-proof masks, protective glasses and gloves to avoid inhalation of dust and direct contact with eyes and skin.
Avoid mixing with strong acids (e.g., hydrochloric acid, sulfuric acid) in large quantities, as it may release trace amounts of acidic fumes.
Storage Requirements
Store in a cool, dry, well-ventilated warehouse; keep away from moisture to prevent caking of anhydrous sodium sulfate and deliquescence of decahydrate.
Separate from strong acids and food raw materials; use sealed plastic or woven bags for packaging, and mark product specifications clearly.
Emergency First Aid
Skin Contact: Rinse the affected area with plenty of running water for 5–10 minutes; no special treatment is needed if no irritation occurs.
Eye Contact: Immediately lift the eyelids and rinse with running water or normal saline for 10–15 minutes; seek medical attention if eye redness or pain persists.
Inhalation: Move the victim to fresh air, keep the airway open; if coughing or chest discomfort occurs, give oxygen and seek medical care.
Ingestion: Drink plenty of warm water to induce vomiting (for conscious persons only); do not induce vomiting for unconscious persons, and send to hospital immediately.