title: Stabilizing Cr species in incinerator fly ashes with/without kaolin addition through a firing process: a molecular study on heated Cr.
abstract: Cr speciation in Cr-sorbing washed incinerator fly ash (IFA) after heating up to 1100°C is temperature dependent. Higher temperature leads to a greater level of chemical reduction of Cr(VI) that is considerably more toxic than Cr(III). Most Cr(VI) sorbed washed IFA is effectively transformed into Cr(III) after heating to 1100°C for 2 h, as indicated by the disappearance of hexavalent pre-edge peak of Cr K-edge X-ray absorption near edge structure (XANES) spectrum. After heating the Cr-sorbing IFA to 100°C and 500°C for 2 h, water-soluble CaCrO4is determined to be the principal Cr species due to the chemical reaction between the sorbed Cr(VI) and CaO components of washed fly ash, based on the comparison between sample and reference XANES spectra. Replacing half of the washed fly ash with kaolin could effectively reduce all Cr(VI) after heating to ≧ 900°C for 2 h.
authors.affiliation: a Department of Environmental Science and Engineering , Tunghai University , Taichung City , Taiwan.
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Wei
authors.affiliation: a Department of Environmental Science and Engineering , Tunghai University , Taichung City , Taiwan.
authors.forename: Hsi-Chih
authors.initials: HC
authors.lastname: Wang
authors.affiliation: a Department of Environmental Science and Engineering , Tunghai University , Taichung City , Taiwan.
authors.forename: Yen-Shiun
authors.initials: YS
authors.lastname: Peng
mesh_terms: D002857:Chromium / Q000737:chemistry*; D060729:Coal Ash / Q000737:chemistry*; D006358:Hot Temperature; D017745:Incineration; D007616:Kaolin / Q000737:chemistry*
chemical_list: D060729:Coal Ash; D002857:Chromium; D007616:Kaolin
keywords: Cr XANES; Cr speciation; Incinerator fly ash; plating sludge; thermal stabilization