Chemical analysis and modes of occurrence of selected trace elements in a coal sample from eastern Kentucky coal bed: White Creek Mine, Martin County, Kentucky

This report provides semi-quantitative data on modes of occurrence of 20 elements in a sample collected from an eastern Kentucky coal from the White Creek Mine, Martin County, Kentucky.The data are in support of the project "Prediction of Trace Element Removal from Coal" -a Cooperative Research and Development Agreement (CRADA) with CQ Inc.The purpose of this CRADA is to apply modes of occurrence information to coal cleaning procedures, specifically a low sulfur central Appalachian coal for this study.Techniques used in this study include sequential selective leaching procedures, scanning electron microscopy, X-ray diffraction analysis, and electron microprobe analysis.Selective leaching results indicate that greate' than 50 percent of the elements Ca, Cd, Mn, Pb, and Zn are associated with HOI-or ammonium acetate-soluble carbonates, iron oxides, or monosulfides; greater than 40 percent of the Al, Be and Cr are associated with HF-soluble silicates; greater than 40 percent of the Co, Cu, Ni, Se, Sb, Th and U are associated with HCI, HF and HNO3 acid-insoluble phases and/or organic matter; and greater than 50 percent of the t-s and Hg is associated with HNCb-soluble pyrite.Due to the high clay content and relatively low pyrite content in this sample, 35 percent of the Fe was associated with th^ HFsoluble silicates while only 25 percent was associated with the pyrite.Thirty-five percent of the Ba is associated with the HF-soluble silicates whereas 40 percent of the B3 was associated with HCI-soluble (and ammonium acetate-soluble) barite.Thirty-five percent of the Mo was associated with the HF soluble clays.The major minerals present in this sample are quartz, kaolinite, and illite, as indicated by scanning electron microscopy and confirmed by X-ray diffraction analysis.The chalcophile elements As, Se, Cu, Ni, Zn, and Cd in most pyrite grains are at or below the detection limit of about 1C 0-200 ppm based on electron microprobe analysis, but two pyrite grains locally showed As concentrations of greater than one weight percent.One of these grains also had over a weight percent of each of the following elements: Co, Cu, Ni, and Se.Lead and Cu were also higher in this grain than in any other grains measured.The results of this project should aid in the development of models for predicting the response of potentially toxic trace elements in commercial coal cleaning procedures.' ' Vi< , ! ' ' ' (.