A promising strategy for the detoxification and immobilization of chromite ore processing residue (COPR) in a spinel-based glass-ceramic matrix is reported in this study. In the search for a more chemically durable matrix for COPR, the most critical crystalline phase for Cr immobilization was found to be a spinel solid solution with a chemical composition of MgCr1.32Fe0.19Al0.49O4. Using Rietveld quantitative X-ray diffraction analysis, we identified this final product is with the phases of spinel (3.5 wt.%), diopside (5.2 wt.%), and some amorphous contents (91.2 wt.%). The partitioning ratio of Cr reveals that about 77% of the Cr was incorporated into the more chemically durable spinel phase. The results of Cr K-edge X-ray absorption near-edge spectroscopy show that no Cr(VI) was observed after conversion of COPR into a glass-ceramic, which indicates successful detoxification of Cr(VI) into Cr(III) in the COPR-incorporated glass-ceramic. The leaching performances of Cr2O3 and COPR-incorporated glass-ceramic were compared with a prolonged acid-leaching test, and the results demonstrate the superiority of the COPR-incorporated glass-ceramic matrix in the immobilization of Cr. The overall results suggest that the use of affordable additives has potential in more reliably immobilizing COPR with a spinel-based glass-ceramic for safer disposal of this hazardous waste. (C) 2016 Elsevier B.V. All rights reserved. Publication name | JOURNAL OF HAZARDOUS MATERIALS, 321 449-455; 10.1016/j.jhazmat.2016.09.035 JAN 5 2017 | Author(s) | Liao, Chang-Zhong; Tang, Yuanyuan; Lee, Po-Heng; Liu, Chengshuai; Shih, Kaimin; Li, Fangbai | Corresponding author(s) | LIU Chengshuai csliu@soil.gd.cn 1. Guangdong Inst Ecoenvironm & Soil Sci, Guangdong Key Lab Agr Environm Pollut Integrated, Guangzhou 510650, Guangdong, Peoples R China 2. Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang 550009, Peoples R China SHIN Kaimin kshih@hku.hk Univ Hong Kong, Dept Civil Engn, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China. | View here for the details
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