Direct and indirect methods for chromium identification in industrial wastes |
| |
Authors: | Edeltrauda Helios Rybicka Michael Jefferson Wilson |
| |
Affiliation: | (1) University of Mining and Metallurgy, Al. Mickiewicza 30, PL-30-059 Krakow, Poland;(2) Macaulay Land Use Research Institute, AB 15 8QH Aberdeen, UK |
| |
Abstract: | The examinations of selected wastes and stream sediments from the vicinity of a chemical plant by sequential extraction procedures and direct methods, SEM/EDX and XRD, were carried out in order to identify the different forms of chromium, particularly as they are released to potential mobility. The results show that the top and bottom waste samples contain 37,756 and 53,650 μg g1 Cr, respectively, but about 7% and 2% of the total chromium type Cr(VI). The chemical extraction results show that the mobility of Cr in the upper part of the waste pile is significantly higher than in the bottom section; the exchangeable form of Cr accounts for 25% and < 1%, respectively, the last one irrespective of redox conditions. About 50% of Cr is associated with the reducible fraction of the top waste, and similar with the residual fraction in the bottom waste. Oxidation of the bottom waste shift some portion of Cr from residual to the moderately reducible fraction. The major Cr-forms in the river sediments are compounded with Fe-oxides. The < 2 μm size fraction of the selected sediment sample, particular enriched in chromium contained up to 73,000 μg g1 Cr with about 95% of this in the moderately reducible fraction, predominantly bound with oxyhydroxides. SEM/EDX and XRD analysis of wastes and river sediment indicate that the main insoluble Cr-phase is ferroan — (Mg, Fe) (Cr, Al)2O4 which would be dissolved mainly in the residual fraction. |
| |
Keywords: | Chemical form chromium industrial wastes mobility sediments SEM/EDX methods sequential extraction XRD methods |
本文献已被 SpringerLink 等数据库收录! |
|