Chemical transformations of ferruginous minerals during the process of oxidation of hard coal

In this paper are given the results of Mössbauer measurements for three samples of coalWK22, MKL, WK16 in which respectively,pyrite, siderite andankerite were the predominant ferruginous minerals present. The results showed that these minerals are transformed tohematite during the oxidation process. A part of hematite appeared in the superparamagnetic phase when pyrite was present in the coal samples. The siderite was transformed to hematite but without the occurrence of its superparamagnetic phase.