What Are the Common Sodium Sulphate Specifications in International Trade?
For global chemical procurement managers, evaluating batch specifications correctly determines whether a shipment will perform seamlessly in production or cause downstream processing issues. Understanding the standard trade parameters helps buyers negotiate contracts effectively and secure consistent raw material quality.
1. Main Purity Grades and Forms in Global Commerce
In international trade, sodium sulphate is traded primarily in two distinct physical states and chemical purity tiers:
Anhydrous Industrial Grade (99 Minimum Purity): The dominant form traded internationally. Supplied as a free-flowing white crystalline powder, it is heavily utilized in laundry detergents (as a bulking agent), glass manufacturing (as a refining agent), and textile dye levelling.
High-Purity / Pharmaceutical Grade (ge 99.5%): Premium-grade material with near-zero heavy metal contamination. It is specified for pharmaceutical excipients, food-grade applications, and sensitive chemical reagents where trace impurities disrupt formulation stability.
Decahydrate Form (Na2SO4 · 10 H2O / Glauber's Salt): A hydrated form containing ten water molecules per formula unit. Traded in specialized agricultural, chill-storage, or regional industrial markets.
2. Key Chemical & Physical Specifications
When reviewing a Certificate of Analysis (COA) from an export supplier, procurement teams must verify five essential parameters:
| Specification Parameter | Standard Export Tolerance | Why It Matters for Production |
|---|---|---|
| Main Content (Na2SO4 ) | ≥ 99.0 (Industrial) / ≥ 99.5 (High Purity) | Dictates active chemical strength and raw material efficiency. |
| Moisture Content | ≤ 0.05% - 0.20% | Low moisture prevents caking and clumping during transit. |
| Whiteness Index | ≥ 85% - 92% | Critical for detergent and paper sectors to maintain product aesthetics. |
| Iron Content ($\text{Fe}$) | ≤ 0.002% - 0.005% (20 - 50ppm) | Prevents unwanted discoloration in glass clarity and textile dyeing. |
| Water Insoluble Matter | ≤ 0.05% | Ensures clean dissolution without leaving abrasive grit in processing tanks. |
3. Particle Size Distribution and Granulation
Physical particle sizing directly affects dissolution rates and pneumatic handling:
· Fine Powder (60–100 Mesh): Dissolves rapidly in liquid formulations, making it ideal for textile dye baths and chemical synthesis tanks.
· Granular Grade (20–60 Mesh): Features low dust emissions and uniform flowability, allowing easy dry-blending into laundry powders without clogging automated hoppers.
4. Packaging, Shipping, and Quality Documentation
Sodium sulphate is non-hazardous and falls under HS Code 2833.11 for international customs clearance. Standard packaging options include:
1.25 kg or 50 kg Woven PP Bags: Lined with inner PE moisture-barrier films to protect against ambient humidity.
2.1000 kg - 1250 kg Jumbo Super Sacks: Tailored for high-volume automated plant discharging.
3.Crucial Documentation: B2B shipments must always be accompanied by a batch-specific Certificate of Analysis (COA), Material Safety Data Sheet (MSDS/SDS), and ISO quality management compliance certificates.
Source Certified Chemical Raw Materials with CNChemist
Securing consistent batch-to-batch chemical quality requires partnering with an established exporter who understands strict international quality standards. CNChemist provides reliable sourcing, quality testing, and international export logistics for industrial chemicals and inorganic salts.
Advantages of Partnering with CNChemist:
· Strict Quality Assurance: High-purity sodium sulphate tested to meet international standards for main content, low iron, and minimal moisture.
· Flexible Packaging & Particle Sizing: Tailored mesh sizes and customized export packaging (palletized bags, jumbo sacks) designed for maritime shipping.
· Complete Trade Compliance: Fully documented supply chains providing COA, SDS, and REACH compliance support for global buyers.
Procurement Checklist for Buyers
Before issuing a Purchase Order (PO):