scope:

This Standard specifies procedures for the determination of ash content of all types of wood, pulp, paper and board.

This Standard embodies two procedures-one specifies ignition at 900°C and the other at 525°C. The former temperature is applicable to all types of wood, pulp, paper and board. The latter temperature is applicable to all types of pulp, paper and board.

The ash may consist of-

(a) mineral matter in the wood or pulp and various residues from chemicals used in manufacture of the pulp;

(b) metallic matter from piping and machinery; and

(c) fillers, pigments, coatings or residues from various additives in the paper or board.

The ash content, of wood pulp, paper and board can be thought of as the residue after ignition or the total inorganic matter. The procedure for ignition, however, needs to be carefully defined. At 900°C any calcium carbonate, a common component of paper and board, will be converted to calcium oxide. Therefore, the ash content, determined at this temperature, might not be a measure of the original mineral content. At 525°C there is minimal decomposition of calcium carbonate, and therefore the ash content at this temperature may be used as a measure of original mineral content, providing the sample does not contain other minerals which decompose at or below this temperature. For example, magnesium carbonate, which can be added to paper to provide particular properties, may be at least partly decomposed to magnesium oxide at 525°C.