高钙铬渣及其解毒后可溶六价铬含量分析方法研究

Evaluation of methods for determination of hexavalent chromium contained in chromite ore processing residue

分析了铬渣中六价铬含量的测定方法、六价铬的浸取方法、解毒铬渣的评价方法等几个方面的问题。通过对比国内外大量的研究结果,指出了铬渣中六价铬浸取评价方法存在的问题。由于铬渣的强碱性及其强大的酸中和能力,所谓的酸液浸取大多名不符实,用硫酸、硝酸、盐酸稀溶液浸取铬渣中六价铬要比USEPA Method 3060A碱消解方法效果差很多;用HJ/T 299—2007和HJ/T 300—2007评价解毒后的铬渣存在很多问题;用GB 5085.3—2007评价铬渣的浸出毒性也有不严密的地方。测定铬渣中六价铬最好用物理方法,例如XANES方法;浸取铬渣中的六价铬宜采用USEPA Method 3060A的碱消解方法。

Hexavalent chromium （Cr^6＋） determination,and extraction protocols from chromite ore processing residue （COPR）, and the evaluation of the harmlessness measures of COPR were reviewed.Problems of some Cr^6＋ leaching protocols of COPR were pointed out by referring to quite a lot of related publications at home and abroad.As the strong alkali and the great acid neutralization capability of COPR ,many so-called Cr^6＋ acid solution extractions are untrue.USEPA Method 3060A leaches much more Cr^6＋ than the diluted aqueous solutions of sulfuric acid, nitric acid or hydrochloric acid.HJ/T 299--2007 and HJ/T 300--2007 methods can not determine genuine Cr^6＋ content of the treated COPR.GB 5085.3-2007 has flaws for evaluating the leaching toxicity of COPR.Best choice for determining Cr＋ content of COPR is physical analysis, such as X-ray absorption near-edge structure analysis;and igs better to leach Cr6 from COPR by USEPA Method 3060A.