Chemical identity and common names
Sodium sulfate, sodium sulphate and disodium sulfate refer to Na2SO4. PubChem lists a molecular weight of 142.04 g/mol for the anhydrous compound and CAS 7757-82-6. “Natrium sulphate” is a language variant that may appear in trade documents. The formula and CAS number are safer identifiers than spelling alone.
Sodium sulfate is not sodium sulfite (Na2SO3), sodium bisulfite, sodium metabisulfite, sodium sulfide or sodium lauryl sulfate. These substances have different chemistry and uses. A procurement document should never shorten the name to “sulfate” or “sulfite” where confusion is possible.
Anhydrous sodium sulfate and Glauber’s salt
| Form | Formula | Buying implication |
|---|---|---|
| Anhydrous sodium sulfate | Na2SO4 | Water-free chemical basis used for many industrial powder applications |
| Sodium sulfate decahydrate (Glauber’s salt) | Na2SO4·10H2O | Contains water of crystallization; gross mass and behavior differ from anhydrous material |
Hydrate identity changes the mass fraction of Na2SO4, storage behavior and process calculation. A quote for “sodium sulfate” is incomplete when the required form is not stated. Do not treat a decahydrate price per tonne as directly comparable with an anhydrous price per tonne.
Properties that matter in industrial use
Sodium sulfate dissolves in water and dissociates into sodium and sulfate ions. Published solubility values depend strongly on temperature, hydrate form and method; a single handbook number should not be used as a plant recipe. For dissolution-sensitive processes, qualify the actual grade using the customer’s water, temperature, agitation, concentration and residence time.
Particle size and bulk density are physical, not purely chemical, properties. They affect dust, flow, storage volume, feeder calibration and dissolution. Moisture and packaging history can change caking or handling even when assay remains compliant. These properties should be specified only when they affect the process.
Material identity also needs to survive across languages and documents. Match the commercial invoice, bag label, specification, SDS and COA to the same form and product code. If a translated name is ambiguous, the formula, CAS number and hydrate description should control the review.
Major industrial-use families
USGS identifies detergents, glass, textiles, pulp and paper and other industrial uses in the historical sodium sulfate market. In powder detergents, sodium sulfate can serve as a formulation filler or processing carrier; it is not the surfactant itself. In textile dyeing, sodium sulfate can act as an electrolyte in selected dye systems. In glass batches, sulfate can serve a formulation-specific fining or oxidation role. The exact function and dose must be set by the formulator, dye technologist or glass technologist.
Other uses depend on specific process chemistry. A broad industrial-use list does not prove food, pharmaceutical, medical, cosmetic or agricultural suitability. Regulated uses require the correct grade, manufacturing controls and current destination-market evidence.
How to read a sodium sulfate specification
- Confirm anhydrous or hydrate identity and the reporting basis for Na2SO4.
- Review moisture or loss on drying and water-insoluble matter.
- Set chloride, calcium, magnesium, iron, free acid or free alkali limits only where relevant.
- Use application-specific requirements for whiteness, color, pH, particle size or bulk density.
- Identify test methods, sampling, retained samples and acceptance rules.
- Connect every commercial shipment to a lot-specific COA.
Storage, handling and environmental controls
Store bags in a dry, covered area and protect them from damaged flooring, roof leaks and condensation. Manage dust and manual handling under the current SDS and site risk assessment. Sodium and sulfate remain dissolved ions in water, so process wastewater and high-salt discharge require site-specific review. Do not infer discharge permission from the product’s general hazard classification.
Frequently asked questions
What is the formula of sodium sulfate?
The anhydrous formula is Na2SO4. The decahydrate form is Na2SO4·10H2O.
Are sodium sulfate and sodium sulphate different?
No. They are spelling variants. Chemical form, grade and specification remain the important distinctions.
Is sodium sulfate the same as SLS?
No. SLS usually means sodium lauryl sulfate, a surfactant with different chemistry and function.
Is every industrial sodium sulfate suitable for food or medicine?
No. Regulated uses require the applicable grade, manufacturing controls and current compliance evidence.
Primary technical references
- PubChem — Sodium Sulfate
- PubChem — Sodium Sulfate Decahydrate
- USGS — Sodium Sulfate Statistics and Information