BCR改进法提取稀土冶炼废渣中的重金属元素Cr、Mn、Zn和Pb

Extraction of Cr, Mn, Zn and Pb from rare earth smelting slag by modified BCR

金属的赋存形态对其生物有效性、环境危害性等非常重要,为探究稀土冶炼废渣中重金属的赋存形态以及潜在风险,本文用改进的顺序提取法(BCR改进法)对酸不溶渣、除放射滤渣和最终中和渣中重金属元素Cr、Mn、Zn和Pb的赋存形态进行研究。结果显示酸不溶渣提取效果最好,最终中和渣提取效果次之,除放射滤渣提取效果最差;酸不溶渣中的Mn和Zn主要以弱酸提取态和可还原态为主,Pb主要以可还原态和可氧化态为主,酸不溶渣中重金属的活性为排序:Zn>Mn>Pb>Cr;最终中和渣中Cr、Zn、Mn和Pb以残渣态为主。

As we know that the occurrence form of metals is very important for their bioavailability and environmental hazards. In order to study the occurrence forms and potential risks of heavy metals in rare earth smelting slag, here we explore the occurrence forms of Cr, Mn, Zn and Pb in acid insoluble slag, radioactive filtering slag and final neutralization slag by means of modified sequential extraction procedure(modified BCR). We show that the extraction effect of acid insoluble residue was the best, final neutralization slag followed, and radioactive filtering slag the worst. We also find that Mn and Zn in acid insoluble slag were mainly in weak acid-soluble fraction and residual fraction, while Pb mainly in residual fraction and oxidizable fraction. Result indicated that the activity of heavy metals in acid insoluble slag was in a sequence of Zn>Mn>Pb>Cr. In addition, Cr, Zn, Mn and Pb were mainly residual fraction, in the final neutralization slag.