Overview
ISO 10376:2011 specifies a laboratory procedure for determining the fines mass fraction of pulps - the portion of a pulp that passes a nominal 76 µm screen or perforated plate. The method uses a perforated metal plate or a single‑screen fibre classifier (e.g. a Britt Dynamic Drainage Jar, BDDJ) after standardized disintegration of the pulp. Results are reported as the fines mass fraction (%) of the oven‑dry test portion and are intended for mechanical and chemical pulps (and most papers that can be fully disintegrated).
Key topics and technical requirements
- Definition of fines: material passing a 76 µm aperture (perforated plate or wire screen).
- Principle: disintegrate pulp, screen under controlled turbulent flow, dry and weigh retained fibre and fines fractions, calculate fines fraction:
- w (%) = 100 × m_fines / (m_fines + m_fibre)
- Sample sizes and screening water:
- Low‑fines pulps (≤ 10 %): test portion 5.0 ± 0.5 g; screening water ≈ 5 000 ml.
- High‑fines pulps (> 10 %): test portion 0.5 ± 0.1 g; screening water ≈ 2 500 ml.
- Apparatus specifics: BDDJ/fibre classifier or equivalent; screen/perforated plate aperture (76 ± 4 µm); stirrer with three‑bladed propeller positioned close to the screen; balance accurate to 1 mg; filter paper (≈90 g/m², e.g. Whatman No. 4).
- Disintegration and concentration: follow ISO 5263 (parts 1–3) and ISO 4119 for pulp concentration prior to screening.
- Precision: method yields improved precision versus McNett classification (see Annexes). Repeatability typically low (single‑digit % CV for many pulps); inter‑laboratory reproducibility is moderate (see Annex A for data).
- Reporting: include reference to ISO 10376, sample ID, test conditions, fines mass fraction (mean of duplicates, three significant figures), and any deviations.
Applications and users
- Who uses it: pulp and paper laboratories, quality control teams, R&D groups, mill process technologists, and third‑party testing labs.
- Practical uses:
- Monitor fines content to assess headbox fines buildup, retention performance, drainage and dewatering behavior.
- Evaluate effects of refining, recycling, and filler load on paper/board properties.
- Compare retention aid performance and process changes that influence fines generation or removal.
Related standards
- ISO 5263‑1 / ‑2 / ‑3 - laboratory wet disintegration of pulps
- ISO 4119 - determination of stock concentration
- ISO 7213 - sampling for testing pulps
- ISO 3310‑1 - test sieves/wire cloth specifications
- ISO 638 - dry matter (oven‑drying) method
- SCAN methods (e.g., SCAN‑CM 66) - comparative studies with McNett classifier
Keywords: ISO 10376, fines mass fraction, pulp testing, fibre classifier, Dynamic Drainage Jar, perforated metal plate, 76 µm screen, pulp quality, laboratory method.