Plan a trial for your application
Leather tanning trials
Use matched pieces from one hide lot. Compare penetration uniformity, shrinkage temperature and color after tanning.
Light-colored leather
Compare iron impurities, shade and the plant’s specified chromium tests. Retain the leather swatch ID.
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 |
|---|---|---|---|
| Chromium oxide (as Cr₂O₃) | Mass fraction | ENVO published powder grade 25±1% | Compare the material as received with its batch COA and check basicity. |
| Basicity | % | ENVO published powder grade 33±2% | Record separately from chromium oxide content and use the same sampling procedure. |
| Water-insoluble matter | Mass fraction | ENVO published powder grade ≤0.10% | Agree the dissolution, filtration and drying conditions. |
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.
From samples to commercial delivery
Packaging and receiving
ENVO lists 25 kg bags. Confirm the liner, powder lot number and bags per pallet.
Storage and handling
On receipt, retain a powder sample and its corresponding tanned leather sample to distinguish incoming-material variation from variation in the hide.
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.
The basic chromium sulfate label example lists gross and net weights separately. Match the lot number to its Cr₂O₃ analysis.
Questions from the plant
Why do hide penetration and chrome fixation vary between lots?
Tan matched pieces from the same hide lot. Check penetration at a cut edge and record the shade of the finished leather.
Does “not detected” on a COA establish compliance with the buyer’s hexavalent chromium limit?
Check the sample matrix, method and quantification limit. Arrange the applicable separate test on the finished leather.
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 chromium oxide content, alkalinity, 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.