Download or read book Transformations of Inorganic Coal Constituents in Combustion Systems. Quarterly Report No. 22, January 1--March 31, 1992 written by and published by . This book was released on 1992 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results from recent UK chromium XAFS analysis of several coal and ash samples are reported. Illinois No. 6 parent coal, Illinois NO. 6 physically beneficiated coal, and two coals from the Penn State Coal Bank (DECS-2 and DECS-12), were found to contain chromium in the +3 oxidation state. No evidence for the carcinogenic and toxic +6 oxidation state (i.e., CrO4−2) was found. Ash samples were generated from each of these coals in a PSIT laboratory scale reactor at 1500°C and 7% oxygen. Subsequent XAFS analysis of these ash samples also identified only Cr+3 in the ash. As discussed further in Section 3, if the results of this study can be considered general for bituminous coals, then the absence of the (+6) chromate state in both the coal and the ash implies that the hazard posed by chromium in coal combustion is small, absent high concentrations of chromium in the ash (> 100 ppM). Of the two major oxidation states of chromium, the CrO4−2 oxidation state can be both toxic and carcinogenic, whereas the Cr{sup 3+} oxidation state at such low concentration levels (