土法炼锌废渣堆中的重金属及其释放规律

Heavy metals and their release in the wastes residue pile at the indigenous zinc smelting area

黔西北地区的土法炼锌使生态环境遭受了严重破坏.用原子吸收等方法对土法炼锌废渣的研究表明,废渣堆pH值呈中性、微碱性,重金属含量很高,Pb、Zn、Cu和Cd的最高含量分别达31631,57178,2367和311.5mg/kg.废渣堆中的重金属含量分布与堆放的废渣类型和堆放时间有关,重金属主要滞留在矿渣层中.矿渣层中的重金属含量随堆放时间的增长而降低,可用负指数方程很好地描述矿渣中的重金属(Pb、Zn和Cd)的自然释放过程.废渣中重金属的总量大,释放时间长,对环境构成威胁.

The eco-environment was seriously damaged by the indigenous zinc smelting in Guizhou Northwest Region. Studies on the waste residue of indigenous zinc smelting with atomic absorption spectroscopy and other techniques indicate that pH values of the waste residue pile are neutral or weak-basic. The heavy metal content is very high, with Pb, Zn, Cu and Cd content maximum of 31631, 57178, 2367 and 311.5 mg/kg, respectively. The distribution of heavy metals in the waste residue pile are relative to the type of waste residue and the piling time. These metals are detained mainly in the slags layer. With prolongation of piling time, the contents of these heavy metals in the slags decrease gradually. The natural releasing processes of Pb, Zn and Cd in the slags can be primely described with minus-exponent equation; and they are hazardous to environment because of their high total contents and long time of release.