Plan a trial for your application
Textile dechlorination after bleaching
Compare treatment at the same residual oxidant target. Record water quality and hydration state of the sample.
Process reducing-agent sourcing
Use representative liquor to evaluate active requirement and insolubles. Retain a sample from each lot.
Purchase specifications and incoming inspection
Include the intended grade or current specification in the enquiry. Use the table to compare selection criteria and inspection conditions. The specification agreed by both parties defines the contractual limits. ENVO public product information · Verify against the ordered grade and lot ↗
| Property | Unit | Published or agreed specification | Test conditions and checks |
|---|---|---|---|
| Sodium thiosulfate pentahydrate | Mass fraction | published pentahydrate grade ≥99% | Express as Na₂S₂O₃·5H₂O. Compare the anhydrous material separately. |
| Water-insoluble matter | Mass fraction | ENVO published pentahydrate grade ≤0.01% | Retest using the filtration method agreed for the grade. |
| Iron | Mass fraction | ENVO published pentahydrate grade ≤0.002% | Distinguish the specification maximum from the measured batch result. |
When approving a sample, record the grade, methods, limits and specification revision. On receipt, match the packing lot number to the lot-specific COA and record the measured values and release decision.
Chemical identity
| Database entry | Molecular or composition formula | Molar mass |
|---|---|---|
| Sodium Thiosulfate | Na2O3S2 | 158.11 g/mol |
The values refer to the compound indicated. Confirm hydrate form, solution concentration and blend composition for the commercial grade.
From samples to commercial delivery
Packaging and receiving
The pentahydrate listing specifies 25 or 1,000 kg bags. For bulk bags, request discharge spout, lifting and moisture-barrier liner details.
Storage and handling
Check the as-received hydrate. Changes in appearance or the proportion of fines do not directly measure purity.
Sample and order lead times
State the concentration or hydrate, initial net quantity, destination and unloading method. Confirm minimum order, pallet or truckload quantity, dispatch point and arrival date separately.
Questions from the plant
Why do equal tonnes provide different reducing capacity?
Compare molar quantities, then verify performance in the actual water sample at the specified endpoint.
Why do the documents mention both anhydrous and pentahydrate forms?
Ask for the actual crystal form and assay basis. Reconcile specification, lot documentation and package label before calculating active cost.
Report a delivery or batch issue
Include the order number, lot number from the package, label photos and inspection records for the affected lot. When retesting, check Hydration state, assay basis, Insoluble matter.
Request documents for your application
TDS · Technical data sheet
For grade selection and sample approval, specify the grade and revision required.
SDS · Safety data sheet
Specify the country or region of use and the required language.
COA · Certificate of analysis
Request a sample COA during supplier review. For incoming inspection, provide the actual lot number.