有色冶炼废渣的矿物学特征与环境活性

通过扫描电子显微镜与X射线衍射仪分析、BCR法三步连续提取及元素化学分析,对某有色冶炼废渣中重金属的赋存状态、环境活性及其释放机理进行研究。研究结果表明:废渣中主要有价金属为Fe,Zn,Cu,Pb,Ag和In等,主要毒害元素为Pb,Cd和As等。废渣矿物相中Fe主要以单质铁、铁的氧化物和硫化亚铁存在,Zn主要以闪锌矿存在,Pb主要以方铅矿存在,Cu和Cd主要以硫化矿物等形式存在;Ag和In则很可能以类质同相镶嵌在闪锌矿晶格中;废渣中Zn,Cd,Cu和Pb主要以残渣态为主;酸可提取态含量相对较低,而可还原态和可氧化态含量相对较高;在我国南方地区,酸沉降、微生物作用及原电池效应共同影响废渣中重金属的溶出,为生物浸出废渣中有价金属,实现其资源化和无害化提供了理论依据。

Mineralogical characteristics and environmental availability of non-ferrous slag

The geochemical distribution,environmental availability and releasing mechanisms of heavy metals from the non-ferrous slag were studied through scanning electron microscope analysis,X-ray diffraction analysis,three-stage BCR sequential extraction procedure and metals element chemical analysis.The results show that the slag mainly includes valuable metals of iron,zinc,copper,lead,silver,and indium,and toxic metals of lead,cadmium,and arsenic,respectively.The mineralogical components of iron in slag mainly contain single iron,iron of oxides and sulfide,the component of zinc is sphalerite,of lead is galena,and that of copper and cadmium is sulfide,respectively.But,the mineralogical components of silver and indium in slag are opaque and probably stud in the crystal lattice of sphalerite with isomorphism.The speciation of zinc,cadmium,copper,and lead in the slag exists mainly in residual forms.The percentage of acidic extractable forms of metals in slag is low while that of reducible and oxidizable forms is high,respectively.In the South of China,the releasing potential of heavy metals from the slag is significantly affected by acid deposition,microbial effect and galvanic effect,and the recycling and toxicity reduction of nonferrous slag through bioleaching is evaluated.