硫铁矿和冶炼废渣中毒害重金属形态分布特征及环境效应的研究

Study on heavy metals' distribution in different geo-chemical species of pyrite mineral and smelting slag and their environmental effect

利用电感耦合等离子质谱法（ICP-MS）研究了粤西大降坪硫铁矿和硫酸生产过程的冶炼废渣中毒害重金属元素Tl、Pb、Cu、Zn、Ni、Co、Cd、Ag、Mo、V和Sr的含量．并进一步结合IRMM连续分级提取法和ICP—MS研究了它们在各个地球化学形态（弱酸可交换态、可还原态、可氧化态和残余态）的含量分布。研究结果表明，硫铁矿矿石和废渣样品中Tl、Pb、Cd、Ag等重金属的含量高于地壳背景值，且矿石中40％～60％的Tl、Cd和Ag赋存于元素的活动态（即弱酸可交换态、可还原态及可氧化态之和），它们在冶炼废渣中活动态的百分含量有所降低。浸出实验和风险评价代码的分析数据进一步表明，硫铁矿矿石和冶炼废渣大部分毒害重金属（特别是Tl、Pb和Cd）在生产利用过程中极易活化进入表生环境．形成极大的环境隐患。

The concentrations of heavy metals （ Tl,Pb, Cu, Zn, Ni, Co,Cd, Ag, Mo, V and Sr） in the pyrite mineral and the pyrite slag produced by sulfuric acid production from the Western Guangdong Province were determined by Inductively Coupled Plasma-Mass Spectrometry （ICP-MS）. Heavy metal concentrations in different geo-chemical species （weak acid exchangeable, reducible, oxidisable and residual） were further analyzed by IRMM sequential extraction combined with ICP-MS. The results showed that the pyrite mineral and the pyrite slag had higher concentrations of Tl, Pb, Cd and Ag than the crustal abundance, and 40% -60% of these metals were associated with the easily-mobile fraction （the sum of weak acid exchangeable, reducible and oxidisable ）. Their percentages of easily-mobile fraction reduced in the pyrite slag. Results of the leaching experiments and the risk assessment code further indicated that most of the studied toxic metals, especially Tl, Pb and Cd, were apt to release into the environment, forming great environmental hazard.