Robert B. Finkelman Allan Kolker 1998 <p>Mode-of-occurrence data are summarized for 13 potentially hazardous elements (Be, Cr, Mn, Co, Ni, As, Se, Cd, Sb, Hg, Pb, Th, U) in coal. Recent work has refined mode-of-occurrence data for Ni, Cr, and As, as compared to previous summaries. For Cr, dominant modes of occurrence include the clay mineral iliite, an amorphous CrO(OH) phase, and Cr-bearing spinels. Nickel is present in Fe-sulfides (pyrite and marcasite) and is also organically bound. Arsenic-bearing pyrite may be the dominant host of As in bituminous coals.</p><p>Concentration data for the 13 HAPs, obtained primarily by quantitative microanalysis techniques, are compiled for mineral and organic portions of coal. HAPs element concentrations are greatest in Fe-sulfides, and include maxima of 2,300 ppm (Co), 4,500ppm (Ni), 4.9wt.% (As), 2,000ppm (Se), 171 ppm (Hg), and 5,500ppm (Pb). Trace-element microanalysis is a significant refinement over bulk methods, and shows that there is considerable trace-element variation on a fine scale for a given coal, and from one coal to another.</p> application/pdf 10.1080/07349349808945578 en Taylor & Francis Potentially hazardous elements in coal: Modes of occurrence and summary of concentration data for coal components article