Sequential leaching of trace elements in coal: A case study from Talcher coalfield, Orissa

The extent of vaporisation and subsequent condensation of many trace elemen ts during coal combustion is largely dependent upon the mode of occurrence of the trace elements, besides many other parameters, Mode of occurrence of a few important trace elements in coals from Talcher coalfield representin g low and high ash type from Karharbari and Barakar Formations is studied b y sequential leaching experiments. It is observed that in both the coal sam ples, Cr and Mn exhibit more affinity towards organic matrix and/or insolub le oxide phases. Pb and Cd are mostly associated with soluble sulphide and oxide minerals. Co is mostly bonded with silicate phases in the coal sample s. No definite mode of occurrence is visualised for Ni from the present stu dy, as it is associated more with the residue indicating its association wi th either organic matrix or insoluble oxide.