Sodium sulfate anhydrous (Na₂SO₄, CAS 7757-82-6), also known as Glauber's salt anhydrous, is primarily used as a filler and flow aid in powdered detergent production. Its functions include adjusting product density, improving powder flowability, and diluting surfactant concentration to control detergency intensity.
Typical technical specifications include:
Purity (Na₂SO₄) ≥99%
Moisture content ≤0.1%
pH (10% aqueous solution): 6.5–8.0
Bulk density: 0.8–1.1 g/ml (depending on production process and particle size distribution)
Particle size: 80–300 mesh (180–50μm), subject to customer formulation requirements
Whiteness ≥80% (required for light-colored detergent appearance)
From a manufacturing perspective, sodium sulfate anhydrous is produced by dehydrating natural mirabilite (Na₂SO₄·10H₂O) or through chemical synthesis. The anhydrous form ensures that no additional moisture is introduced during mixing, preventing surfactant caking. In the post-dosing stage of detergent powder production, sodium sulfate is typically added during the dry mixing phase and blended with surfactants and builders for 10–15 minutes.
For quality control, each batch should be tested for moisture (≤0.1%), chloride (Cl ≤0.05%), iron (Fe ≤30 ppm), and other impurities. Packaging commonly uses 25kg bags with PE liners or 1000kg jumbo bags. Storage requires moisture protection, with relative humidity controlled at ≤60%. Excess moisture may cause product caking, affecting discharge stability from automated packaging lines.
