Long-term treatment issues with chromite ore processing residue (COPR)

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dc.contributor.author Moon, Deok Hyun
dc.contributor.author Wazne, Mahmoud
dc.contributor.author Dermatas, Dimitris
dc.contributor.author Christodoulatos, Christos
dc.contributor.author Sanchez, Adriana M.
dc.contributor.author Grubb, Dennis G.
dc.contributor.author Chrysochoou, Maria
dc.contributor.author Kim, Min Gyu
dc.date.accessioned 2016-03-01T12:01:03Z
dc.date.available 2016-03-01T12:01:03Z
dc.date.copyright 2007
dc.date.issued 2016-03-01
dc.identifier.issn 0304-3894 en_US
dc.identifier.uri http://hdl.handle.net/10725/3227
dc.description.abstract A pugmill treatability study was conducted to remediate chromite ore processing residue (COPR) using ferrous sulfate heptahydrate (FeSO4·7H2O) as a reductant. Two different types of COPR, with respect to particle size and mineralogy, were tested in this study. Two different stoichiometric ratios of FeSO4·7H2O to Cr6+ (5× and 8×) were applied to reduce Cr6+ to Cr3+. The effectiveness of FeSO4·7H2O treatment was assessed using the toxicity characteristic leaching procedure (TCLP) tests and X-ray absorption near edge structure (XANES) analyses. TCLP results obtained from the pugmill treatability study showed that TCLP Cr concentrations were less than the TCLP regulatory limit of 5 mg/L upon 8× FeSO4·7H2O treatment for up to 420 days but may fail to meet this regulatory limit in the long-term. XANES results obtained from samples cured for 300 days showed that all of the treated samples failed the New Jersey Department of Environmental Protection (NJDEP) clean up level for Cr6+ of 240 mg/kg. However, the Cr6+ concentration from the sample with the smaller particle size approached 240 mg/kg (338 mg/kg), suggesting that particle size reduction prior to the addition of reductant may improve the effectiveness of the treatment. COPR heaving was investigated with unconfined swell tests upon 5× and 8× FeSO4·7H2O treatment. The formation of ettringite, an expansive material, was investigated following the swell tests using X-ray powder diffraction (XRPD). Significant heaving (>50 vol%) was observed at curing times of 138 days for the 5× treatment and the ettringite formation was identified by XRPD analyses. en_US
dc.language.iso en en_US
dc.title Long-term treatment issues with chromite ore processing residue (COPR) en_US
dc.type Article en_US
dc.description.version Published en_US
dc.title.subtitle Cr6+ reduction and heave en_US
dc.author.school SOE en_US
dc.author.idnumber 201205627 en_US
dc.author.woa N/A en_US
dc.author.department Civil Engineering en_US
dc.description.embargo N/A en_US
dc.relation.journal Journal of Hazardous Materials en_US
dc.journal.volume 143 en_US
dc.journal.issue 3 en_US
dc.article.pages 629-635 en_US
dc.keywords Chromium (Cr) en_US
dc.keywords Chromite ore processing residue (COPR) en_US
dc.keywords Ettringite en_US
dc.keywords Ferrous sulfate heptahydrate (FeSO4·7H2O) en_US
dc.keywords Heaving en_US
dc.keywords X-ray absorption near edge structure (XANES) en_US
dc.keywords X-ray powder diffraction (XRPD) en_US
dc.identifier.doi http://dx.doi.org10.1016/j.jhazmat.2007.01.013 en_US
dc.identifier.ctation Moon, D. H., Wazne, M., Dermatas, D., Christodoulatos, C., Sanchez, A. M., Grubb, D. G., ... & Kim, M. G. (2007). Long-term treatment issues with chromite ore processing residue (COPR): Cr 6+ reduction and heave. Journal of hazardous materials, 143(3), 629-635. en_US
dc.author.email mahmoud.wazne@lau.edu.lb
dc.identifier.url http://www.sciencedirect.com/science/article/pii/S0304389407000386

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