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Identification of Cr(VI) speciation in ferrous sulfate-reduced chromite ore processing residue (rCOPR) and impacts of environmental factors erosion on Cr(VI) leaching.
Journal of Hazardous Materials ( IF 12.2 ) Pub Date : 2019-03-23 , DOI: 10.1016/j.jhazmat.2019.03.097
Yao Song 1 , Jing Li 2 , Miao Peng 2 , Ziqi Deng 2 , Jianjun Yang 3 , Weizhen Liu 1 , Zhenqing Shi 1 , Zhang Lin 1
Affiliation  

The issue that the residual Cr(VI) in the reduced chromite ore processing residue (rCOPR) is slowly released during deposition has attracted increasing attention. However, the speciation and leaching behaviors of Cr(VI) in rCOPR are still not clear, which is essential for revealing the release mechanism of Cr(VI). In this study, ettringite was determined to be the host phase of Cr(VI) in ferrous sulfate-reduced COPR by scanning electron microscopy (SEM), microfocus X-ray fluorescence spectroscopy (μ-XRF) and aberration-corrected scanning transmission electron microscopy (Cs-STEM). This is because the channel structure of ettringite makes it relatively easy for sulfate to be replaced by chromate with similar structure and thermochemical radius. Furthermore, the investigation on the leaching behavior and mechanism of Cr(VI) in rCOPR eroded by environmental factors showed that carbonates, sulfates and acid can promote the release of Cr(VI). Among them, the erosion effect of HCl on rCOPR is weaker than that of Na2CO3 and Na2SO4 because rCOPR possesses a high buffering reserve of alkalinity. In addition, the erosion of rCOPR by Na2CO3 and Na2SO4 can change Cr(VI) speciation in rCOPR. The results implied that the environmental risk of Cr(VI) release during the deposition of rCOPR should deserve careful assessment.

中文翻译:

硫酸亚铁还原的铬铁矿矿石加工残渣(rCOPR)中Cr(VI)形态的鉴定以及环境因素侵蚀对Cr(VI)浸出的影响。

在沉积过程中,还原的铬铁矿矿石加工残留物(rCOPR)中的残留Cr(VI)缓慢释放的问题已引起越来越多的关注。然而,rCOPR中Cr(VI)的形态和浸出行为仍不清楚,这对于揭示Cr(VI)的释放机理至关重要。在这项研究中,通过扫描电子显微镜(SEM),微焦点X射线荧光光谱(μ-XRF)和像差校正的扫描透射电子显微镜,钙矾石被确定为硫酸亚铁还原的COPR中Cr(VI)的主体相。 (Cs-STEM)。这是因为钙矾石的通道结构使得硫酸盐相对容易被具有相似结构和热化学半径的铬酸盐替代。此外,对环境因素腐蚀后的rCOPR中Cr(VI)的浸出行为及其机理的研究表明,碳酸盐,硫酸盐和酸均可促进Cr(VI)的释放。其中,HCl对rCOPR的腐蚀作用弱于Na2CO3和Na2SO4,因为rCOPR具有较高的碱缓冲缓冲作用。此外,Na 2 CO 3和Na 2 SO 4对rCOPR的腐蚀可以改变rCOPR中的Cr(VI)形态。结果表明,rCOPR沉积过程中Cr(VI)释放的环境风险值得认真评估。Na2CO3和Na2SO4对rCOPR的侵蚀会改变rCOPR中的Cr(VI)形态。结果表明,rCOPR沉积过程中Cr(VI)释放的环境风险值得认真评估。Na2CO3和Na2SO4对rCOPR的侵蚀会改变rCOPR中的Cr(VI)形态。结果表明,rCOPR沉积过程中Cr(VI)释放的环境风险值得认真评估。
更新日期:2019-03-25
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