BS ISO 20360:2020,Brown coals and lignites – Determination of the volatile matter in the analysis sample: one furnace method.BS ISO 20360:2020 pdf free download.
BS ISO 20360:2020 specifies a method of determining the volatile matter of brown coals and lignites by the one furnace method.
The test of volatile matter is empirical and, in order to obtain reproducible results, it is essential that the rate of heating, the final temperature and the overall duration of the test are carefully controlled. It is also essential to exclude air from the coal during heating to prevent oxidation. The fit of the crucible lid is, therefore, critical. The moisture content of the sample is determined at the same time as the volatile matter so that the appropriate correction can be made.
To arrive at a valid comparison of volatile matter results conducted in different laboratories, it is essential that the moisture condition of the test samples in the two laboratories is within the expected variance of the moisture test. If a sample is re-equilibrated with the laboratory atmosphere or partially dried in one laboratory and not the other then oxidation can and will most definitely occur for brown coals and lignites. Oxidation will alter the, as-determined, volatile matter of a test sample.
The dry basis precision for volatile matter includes a variance contribution from the moisture determination and potentially a covariance component, both of which can influence the precision statistics for volatile matter on a dry basis.
Mineral matter associated with the sample may also lose mass under the conditions of the test, the magnitude of the loss being dependent on both the nature and the quantity of the minerals present.