安徽铜陵杨山冲尾矿库尾砂重金属元素的迁移规律

安徽铜陵杨山冲尾矿库使用期为1966—1990年，堆积了近1 308×104 t尾矿，选择该尾矿库进行尾砂重金属迁移规律研究.结果表明:在自然风化条件下，Cu，As，Hg，Cd和Pb的淋滤迁移速度相对较快，Zn略慢；Zn，Pb，Hg和Cd在50～60 cm深处产生了二次富集；不同位置的尾砂中重金属迁移规律有一定差异，低洼区Zn，As和Cd等在表层形成局部富集，100 cm以内浅层尾砂中也有部分重金属元素二次富集；经过长期风化氧化和淋滤作用，浅层尾砂中的重金属元素易淋滤部分大多被淋失，风化后尾砂中Cu，Pb，As和Hg以残渣态为主要赋存形式，其含量占全量比例均大于35%，其次为铁锰氧化态，其中Zn和Cd以铁锰氧化态含量在表层最高.在尾矿库表面植草能减少扬尘，也可能造成部分重金属元素含量在表层异常升高，影响尾矿库的进一步改造和复垦. 

Migration of Heavy Metals in Yangshanchong Tailings Impoundment in Tongling,Anhui Province

The Yangshanchong tailings impoundment in Tongling mining area,Anhui Province,was investigated in order to determine the migration and transformation behaviors of heavy metals in mine tailings.The tailings impoundment was in operation between 1966 and 1990,and approximately 1308×10~4 t of tailings accumulated there.The results showed that the transfer rates of Cu,As,Hg,Cd,and Pb were relatively fast,while that of Zn was slower.Zn,Pb,Hg,and Cd got secondarily enriched 50～60 cm from the surface down.There was some discrepancies in the heavy metal migration characteristics in different places.At the shallower part of the tailings impoundment,Zn,As,and Cd deposited near the tailings surface,resulting in metal ions enrichment in the shallower part.The heavy metal transformation characteristics at different depths were dissimilar.Through the long process of weathering and eluviating chronically,the most easily eluviating heavy metals in tailings above 100 cm had been eluviated.The major existing state of Cu,Pb,As and Hg was the residual state,with the fraction being greater than 35%,and the secondary state was the Fe-Mn oxidation state. Surface grass planting can decrease dust flying upwards,but can also cause some elements to enrich,which might hinder the rehabilitation in the tailings impoundments.