Leaching of Metals from High Carbon Fly Ash Mixed Soils

摘要: Fly ash produced by power plants in the United States occasionally contains significant amounts of unburned carbon due to use low nitrogen-oxide and sulphur-oxide burners recent years. This cannot be reused concrete production its reactivity with air entrainment admixtures is largely placed landfills. Highway structures have high potential for large volume fly ashes (HCFAs). However, such applications, even though mechanical properties ash-amended highway base layers embankments are deemed satisfactory, one key issue that precludes built groundwater impacts caused metals ash. This study was conducted evaluate leaching from stabilized amended embankment structures. Three different laboratory tests: (1) batch water leach tests, (2) toxicity characteristics procedure (3) column test two numerical modeling analyses: WiscLEACH, MINTEQA2, were carried out. Analysis on eight locally available sandy soil materials mainly used layer Laboratory results indicated an increase content mixtures yielded leached metal concentrations except Zn metal. The pHs had metals. Cr, Zn, Al, As Se increasing pH while Ba, B, Cu, Fe, Mn, Sb, V decreasing. Numerical model WiscLEACH simulate behavior HCFA predicted field significantly lower than obtained decreased time distance dispersion vadose zone. Numerical MINTEQA2 solubility controlled As, Sb Speciation analyses present at their less or non-toxic forms.