96/02231 Determination of the strength of metallurgical coke

Abstract

The molecular coordination of trace levels of Zn (1–2 wt%) in natural sediments from an acid mine drainage and of V, Cr, and Mn (10–300 ppm) from weathered hydrothermal soils was examined by synchrotron X-ray absorption spectroscopy (XAS) at ambient and cryogenic (≈10 K) temperatures. XAFS analyses of mine drainage sample spectra show that, with increased weathering, Zn coordination changes from a sulfide phase in its host mineral, sphalerite (ZnS), to coordination indicative of hydroxide phases. In samples with silica, carbonate, and iron-hydroxide phases (3–54 wt% Fe(OH)3), the local atomic Zn environment changes with the total amount of bulk iron hydroxide, bu Zn is not incorporated into carbonate or silica phases. Analysis of pre-edge and K-edge spectral features of very low concentrations of V, Cr, and Mn in oxidized, kaolinite-rich soils from hydrothermal areas indicates reduced valences states for these ions (V3+, 4+, Cr3+, Mn2+) and suggests trapping of metals under paleo-reducing conditions during clay formation.