Dept. of Civil and Environmental Engineering, Univ. of Connecticut, Storrs, CT, United States.
J Hazard Mater. 2020 Jul 5;393:122385. doi: 10.1016/j.jhazmat.2020.122385. Epub 2020 Feb 22.
The microstructure of Chromite Ore Processing Residue (COPR) derived from the soda ash roasting process was investigated prior to and after removal of water exchangeable chromate using a host of microscopy and spectroscopy techniques. Soda ash COPR consists mostly of a magnesioferrite (MgFeO) matrix that has substantial substitution of trivalent chromium (Cr) for iron. The chromite particles are generally larger than the overall particle size distribution of COPR, containing most of the Cr mass in areas that are greater than 20 μm in diameter; chromite particles are also associated with most of the non-exchangeable hexavalent Cr (Cr(VI)), even though the binding mechanism is not well understood. The remaining non-exchangeable Cr(VI) was found in association with the surrounding Si- and Al-matrix, with spectroscopic evidence of the presence of Cr(VI)-hydrotalcite.
采用多种显微镜和光谱技术研究了苏打灰焙烧工艺产生的铬铁矿加工残渣（COPR）在去除水可交换铬前后的微观结构。苏打灰 COPR 主要由镁铁尖晶石（MgFeO）基质组成，其中三价铬（Cr）对铁有大量取代。铬铁矿颗粒通常大于 COPR 的总体粒度分布，其大部分 Cr 质量集中在直径大于 20μm 的区域；铬铁矿颗粒也与大部分不可交换的六价铬（Cr(VI)）有关，尽管其结合机制尚不清楚。其余不可交换的 Cr(VI) 与周围的 Si 和 Al 基质有关，光谱证据表明存在 Cr(VI)-水滑石。
