巴里富碳酸盐硫化物尾矿中重金属的赋存状态  

Occurrence State of Heavy Metals in the Carbonate-rich Sulfide Tailings in Bali Inactive Impoundment,Dachang Tin-polymetallic Mine(Guangxi,China)

作　　者：雷良奇[1] 莫斌吉[1] 付伟[1] 莫佳[1] 史振环 陈斯耐 

机构地区：[1]桂林理工大学地球科学学院,广西桂林541004

出　　处：《地球与环境》2014年第5期604-610,共7页Earth and Environment

基　　金：国家自然科学基金项目(41272394;40972220;41102051)

摘　　要：本文以广西大厂锡石-硫化物矿区巴里尾矿库的富碳酸盐尾矿（堆放了20余年）作为研究对象,采用BCR三步提取法研究Zn、Cd、Pb和As的化学形态分量以及其总含量在该尾矿铅垂剖面中的分布,并结合尾矿的结构构造、次生和原生矿物成分及其变化等分析,探讨在氧化/酸化条件下富碳酸盐尾矿中重金属的释放机制。研究结果表明：（1）尾矿下层原尾矿中重金属主要以稳定或较稳定的残渣态（As、Pb、Zn、Cd）、氧化物结合态（Pb）及硫化物结合态（Zn、Cd）形式赋存。在酸水淋滤作用下,原尾矿中重金属的释放顺序为Cd≈Zn〉Pb〉As;（2）尾矿上部厚层状氧化硬层（厚度1～1.5m）中,Zn、Cd以酸可溶态大量富集,具有较强的迁移性;As、Pb主要以残渣态以及氧化物结合态赋存,其迁移性较差。因此,富含碳酸盐的硫化物尾矿经过氧化作用具有释放多种重金属的潜能。由于这类尾矿中各重金属的赋存状态存在差异性,因此对其迁移性及环境效应须具体分析。To probe into the mechanism of heavy metals release from carbonate-rich sulfide tailings （CRSTs） subjected to the ox- idation/acidification, the study focused on the Bali CRSTs, piled more than 20 years, in Dachang cassiterite polymetallic sulfide mine （Guangxi, China）. By investigating the distribution of the chemical speeiation （BCR three-step sequential extraction pro- cedure） and total contents of heavy metals （Zn, Cd, Pb, As） on a plumb profile in Bali tailings impoundment, discussing it on the basis of the tailings structure, secondary and primary mineral composition and its change, this paper indicated that： （1） Heavy metals in the original railings of lower profile occurred mainly as stable or relatively stable forms, i.e. residual fraction （As, Ph, Zn, Cd）, Fe-Mn oxide bound fraction （Pb） and sulfide bound fraction （Zn, Cd）. The mobility of metals in the origi- nal tailings leached by acid water followed the order Cd≈Zn〉Pb〉As. （2） In the hard layer （hardpan, 1～1.5 m thick） of up- per profile, Zn and Cd occurred mainly as acid soluble speciation, which are of stronger mobility, while As and Pb occurred mainly as residual fraction and Fe-Mn oxide bound fraction, which are of weaker mobility. Therefore, the CRSTs subjected to oxidation possess the potential to release multiple heavy metals. Because the heavy metals in the CRSTs were not identical in occurrence state, their mobility and environmental effect should be considered separately.

关 键 词：碳酸盐型尾矿 尾矿组构 重金属化学形态 矿山环境 大厂锡矿 

分 类 号：X142[环境科学与工程—环境科学]