?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F20014%2F&rft.title=Investigation+of+Environmental+Impacts+of+Beneficial+Reuse+of+Bauxite+Residue+in+Coal-Refuse+Area+Based+on+a+Hydro-Thermal-Geochemical+Model&rft.creator=Xu%2C+Yi&rft.description=The+waste+of+coal+mining+results+in+numerous+piles%2C+which+produce+acid+mine+drainage+(AMD)+and+deteriorate+water+quality.+Also+ions+from+the+refuse+piles%2C+including+sulfate%2C+ferric+and+ferrous+iron+are+continuously+leached+from+these+coal-refuse+piles.+Bauxite+residue%2C+a+byproduct+from+alumina+refining+process%2C+has+a+relatively+high+pH.+If+bauxite+residue+is+innovatively+mixed+with+the+coal+refuse%2C+the+issues+associated+with+these+two+wastes+(e.g.%2C+high+and+low+pH+values)+may+be+solved.+Also%2C+the+concentrations+of+leached+ions+will+be+reduced+significantly.+%0D%0A++++This+study+investigates+the+impacts+of+bauxite+residue+%2B+coal+refuse+on+the+environment+through+a+hydro-thermal-geochemical+model+(HTGCM)+in+combination+with+field+measurements+and+laboratory+analysis.++This+dynamic+model+accounts+for+the+processes+of+water+cycle%2C+pyrite+oxidation%2C+oxygen+diffusion%2C+solute+transport%2C+thermal+transport%2C+pH+calculation+and+other+secondary+reactions.+The+Distributed+Hydrology+Soil+and+Vegetation+Model+(DHSVM)+is+the+basic+framework+based+on+which+the+HTGCM+model+is+developed.++The+HTGCM+model+developments+include+three+main+stages%3A+(1)+improving+the+DHSVM+hydrological+model+and+coupling+the+algorithm+of+pyrite+oxidation+to+DHSVM%2C+(2)+developing+thermal+transport+and+including+the+heat+transport+from+the+oxidation+process%2C+and+(3)+coupling+a+geochemical+model+and+calculating+more+chemical+reactions.+%0D%0A++++The+modeling+studies+and+the+field+observations+lead+to+the+following+main+findings%3A+(1)+the+chemical+concentrations+in+the+amended+zone+are+reduced+while+the+pH+value+is+ameliorated+to+be+less+acidic%3B+(2)+the+chemical+concentrations+in+the+non-amended+zone+also+decrease+but+not+as+significantly+as+in+the+amended+zone+in+the+short-term+period%3B+(3)+it+appears+that+there+may+be+a+range+of+preferred+depth+for+the+amended+zone+to+be+more+effective%3B+(4)+heat+released+from+the+pyrite+oxidation+increases+the+soil+temperature%3B+(5)+the+effect+of+plants+on+soil+temperature+is+restricted+to+a+vegetation-impact+depth%3B+and+(6)+impacts+of+the+amended+zone+on+the+deep+non-amended+zone+can+be+seen+through+a+long-term+simulation.%0D%0A++++This+work+provides+new+insights+into+the+remediation+studies+and+may+lead+to+a+paradigm+shift+in+the+AMD+treatment+strategy+in+the+future.&rft.date=2014-03-13&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F20014%2F1%2FYiXu_etd2013_submitETD.pdf&rft.identifier=++Xu%2C+Yi++(2014)+Investigation+of+Environmental+Impacts+of+Beneficial+Reuse+of+Bauxite+Residue+in+Coal-Refuse+Area+Based+on+a+Hydro-Thermal-Geochemical+Model.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++