Overview
ISO 2144:2019 specifies a standardized laboratory method for determining the residue (ash content) on ignition at 900 °C for paper, board, pulps and cellulose nanomaterials. The standard covers sample preparation, apparatus, incineration and result expression to obtain high-precision measurements (0.01 % or better). It applies to all product types including nanoscale cellulose materials (cellulose nano-objects) that can exhibit behaviours distinct from bulk pulps or paper.
Key topics and technical requirements
- Scope and precision: Applicable to paper, board, pulp and cellulose nanomaterials; designed to achieve measurement precision of 0.01 % or better.
- Principle: Weigh test specimen in a heat‑resistant crucible, incinerate in a muffle furnace at 900 °C ± 25 °C, measure residue (ash) and express result on a dry (moisture‑free) basis. Moisture/dry‑matter is measured on a separate specimen.
- Apparatus: Heat‑resistant crucibles (platinum, ceramic, silica), muffle furnace (900 °C ± 25 °C), analytical balance with readability of 0.1 mg or better, desiccator.
- Sampling & specimen: Follow ISO 186 for paper/board and ISO 7213 for pulps when evaluating lots. Test specimen mass: at least 1 g (dry basis) and normally sufficient to yield ≥10 mg ash; for very low‑ash materials smaller residues (≥2 mg) are acceptable but precision may decrease.
- Cellulose nanomaterials: No single sampling method; wet suspensions must be dried (heating, freeze‑drying, spray‑drying) and homogenized before sampling. Avoid filtration that can remove dissolved inorganics. Chemically modified nanomaterials may contain cations (Na, Ca, organic ammoniums) influencing ash.
- Interpretation caveats: Ash measured at 900 °C relates to mineral content but is not an exact determination of specific pigments or fillers. Loss on ignition of pigments varies (example: china clay ~86–89 % residue; calcium carbonate ~56 %), and some soluble inorganics (e.g., NaCl) can be lost during ignition.
Applications and users
- Quality control and lot verification in paper and board manufacturing
- Pulp mills and pulp testing laboratories
- Materials characterization for cellulose nanomaterials and nanocellulose producers
- R&D teams assessing filler/pigment content, contamination or mineral impurities
- Regulatory and conformity testing where standardized ash measurement is required
Related standards
Keywords: ISO 2144:2019, ash content, residue on ignition, 900 °C, paper testing, pulp testing, cellulose nanomaterials, nanocellulose, muffle furnace, sampling, analytical balance.