1. Sample identification
Record product or sample name, sample code, batch/lot, supplier/source, sampling date, test date and operator.
2. Water information
Record water source, volume, initial temperature and, where relevant, pH, hardness or conductivity. Confirm that the mixing container is clean and free from polymer or salt contamination.
3. Suspension preparation
Record bentonite mass, mixer ID, initial mixing time, conditioning start/end and re-mixing time. The common reference suspension is 22.5 g / 350 mL.
4. Rheology
Record R600 and R300, then calculate PV, YP, YP/PV and AV. Confirm R300 ≤ R600 and PV >0 when reporting YP/PV.
5. Filter press
Record apparatus, filter paper, temperature and pressure. Confirm that the 0–7.5 minute filtrate is discarded and record Vc for the 7.5–30 minute interval.
V = 2 × Vc
6. 75 µm wet sieve
Record sample mass, dispersant, mixing time, sieve, wash pressure, wash time and dry retained mass. Calculate residue above 75 µm as mass percent.
7. Optional moisture QC
Moisture may be recorded as an internal QC parameter. State whether the result is as received or on a defined dry basis.
8. Result summary
Summarize R600, YP/PV, filtrate volume and residue above 75 µm. Use “within reference”, “outside reference”, “not entered” or “invalid” rather than certification language.
This checklist is a laboratory workflow aid and does not constitute API certification or formal conformity assessment.