安徽铜陵水木冲尾矿重金属赋存状态及污染特征研究

A study of modes of occurrence and pollution characteristics of heavy metals in Shuimuchong tailings of Tongling,Anhui Province

为探讨富硫化物尾矿酸化及重金属污染特征,选择安徽铜陵水木冲尾矿库浅层(0～90 cm)剖面为研究对象,对其结构特点、矿物组成、重金属(Pb、Cd、Zn、Ni、Cr、Mn、Cu和As)含量及赋存形态进行研究。结果表明,该尾矿库浅层出现分层现象,即表层为强硬化层,向下依次为弱硬化层和松散层,且呈酸性;矿物主要以辉石、长石、云母和石膏为主,由浅及深,金属硫化物及碳酸盐型矿物特征峰呈现增强的趋势;重金属呈现两种富集类型:表层(0～30cm,As、Pb)富集和中部(40～60 cm,Cd、Cu、Mn、Ni、Zn和Cr)富集型,其中Cu、Cd、As污染较为严重。由相关性分析可知,部分金属之间存在一定的伴生性,且p H值是影响重金属迁移的重要因素之一。该尾矿重金属主要以残渣态为主,其中Pb的潜在迁移能力最强,As最弱,顺序为Pb> Cd> Zn> Ni> Cr> Mn> Cu> As。

In order to explore the characteristics of acidification and heavy metal pollution in the sulfide-rich tailing pond, the authors chose the shallow （0 - 90 cm） section of Shuimuchong tailing reservoir in Tongling of Anhui Province as the research object. Its structural characteristics, mineral composition, heavy metals （Pb, Cd, Zn, Ni, Cr, Mn, Cu and As） content and morphology were studied in detail. The results show that the shallow layer of the tailings reservoir exhibits stratification, that is, the surface layer is strong hardened layer, followed by weakly hardened layer and loose layer, with an acidic environment. Tailing minerals are mainly pyroxene, feldspar, mica and gypsum, and are characterized by the fact that from shallow part to deep part, characteristic peaks of metal sul- fides and carbonate minerals tend to be strengthened. Heavy metals show two types of enrichment： the top layer （0 30 cm, As, Pb） enrichment type and the middle （40 - 60 cm, Cd, Cu, Mn, Ni, Zn and Cr） enrichment type, in which Cu, Cd, As pollution is relatively serious. According to the correlation analysis, there exist some associat- ed types between some metals, and pH is one of the important factors affecting the migration of heavy metals. The tailing heavy metals are mainly in the residual state, with Pb having the strongest potential migration potential, and As having the weakest potential, varying in order of Pb 〉 Cd 〉 Zn 〉 Ni 〉 Cr 〉 Mn 〉 Cu 〉 As.