Quantitative determination of the mineral-matter content of coal by a radiofrequency -oxidation technique
Review articleOpen access
1973/01/01 Full-length article DOI: 10.1016/0016-2361(73)90010-0
AbstractThe development of a low-temperature (≈150 °C) radiofrequency-oxidation technique as a routine laboratory method for the quantitative determination of the mineral-matter content of coal is described. The main advantage of the method over air-oxidation (370 °C) and acid-extraction methods is that isolation of the unaltered mineral matter permits a more accurate expression of coal analyses on a dry mineral-matter-free basis. Comparison with the air-oxidation method has demonstrated the superiority of the radiofrequency-oxidation method for retention of carbonate and sulphide minerals; reproducibility is generally similar. The radiofrequency-oxidation method yields higher results for the percentage of mineral matter than the air-oxidation method. The differences between the combined water contents of the mineral-matter samples prepared by the two methods indicate that the air-oxidation method partly dehydrates clay minerals and that the radiofrequency-oxidation method produces results closer to the true mineral-matter contents. Other advantages — independence of extra analytical determinations, lower elapsed time and labour costs, applicability to a wider range of coals — are detailed in the Conclusions.
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