Modes of occurrence of trace and minor elements in some Australian coals

The modes of occurrence of the trace elements in six Australian coals are reported, together with the nature and percentages of the minerals present. The trace elements studied were As, B, Be, Bi, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Th, TI, U and Zn, as well as the minor elements S and Fe. The modes of occurrence were determined chemically by sequential extraction. For comparison, X-ray absorption fine structure (XAFS) and near edge structure (XANES) spectroscopies were used to determine the modes of occurrence of As, Pb, Ni,S and Zn in four of these six coals and Fe-57 Mossbauer spectroscopy was used to estimate the Fe-species (or forms) occurring in the same four coals. The results obtained were compared with those published on coals generally in the literature. The integrated results provide the most extensive set of information published to-date on the modes of occurrence of trace elements in Australian coals. (C) 2011 Elsevier B.V. All rights reserved.