This Standard sets out two methods for the determination of mineral matter in coal, and a method for determination of water of constitution.

The methods for mineral matter determination are as follows:

(a) Radio-frequency oxygen plasma oxidation.

(b) Air oxidation (370°C).

Both methods are known as low-temperature oxidation techniques. The radio-frequency method yields a residue that contains essentially the original unchanged mineral matter of the coal, and is suitable for semi-quantitative analysis of the mineral matter composition. Predictable alteration of some minerals occurs in the air oxidation process, and appropriate empirical corrections are made.

NOTE:

1 For the applicability of this Standard to lower rank coals, reference should be made to Appendix A.

2 It is advisable to use the radio-frequency oxygen plasma oxidation method for coals of high ash, due to significant irreversible loss of water of constitution in the air oxidation method.