模拟实验研究煤矿酸性水中Co、Ni、Zn、Cd、Al、Cr、As、Pb可溶性金属迁移行为

通过模拟煤矿酸性水环境,对来自2个不同产地的煤系非均质黄铁矿样品进行了不同固液比的淋滤实验,对反应体系物理化学状态以及其中的Co、Ni、Zn、Cd、Al、Cr、As、Pb8种元素的释放行为进行了长达312h跟踪检测和对比.结果显示,在2种不同来源的煤系黄铁矿样品反应体系中,Co、Ni、Zn、Cd的释放行为均为持续升高,说明这些元素的释放受体系中物理化学状态的影响相对较小,在液相中具有较高的迁移行为;Al、Cr、As、Pb在不同样品体系中的释放行为差异较大,受到体系pH值、吸附及共沉淀作用等因素的影响,是相对不易迁移的元素.煤矿酸性水环境中元素释放和迁移行为主要受到黄铁矿的氧化还原反应速率、反应体系介质pH值和围岩矿物学性质3个宏观因素控制.

Simulating experiments to the soluble metals migration of Co,Ni,Zn,Cd,Al,Cr,As and Pb in acid coal-mine drainage

Batch leaching experiments were carried out, with different solid-to-liquid ratios like those in the acid coal-mine drainage,for heterogeneous pyrite samples from two coal seams. The state of reaction systems and the migratory behavior of such 8 elements as Co, Ni, Zn, Cd, Al, Cr, As and Pb were measured for a period of 312 hours. The results from 4 systems of different solid-to-liquid ratios show that the concentrations of Co, Ni, Zn and Cd continuously increase. This indicates that the elements were affected little by the physicochemical state of the systems and thus easily mobilized by the leaching solution. On the other hand, the concentrations of Al, Cr, As and Pb vary greatly under the same conditions. This suggests that the elements were affected by the pH value, absorption and co-precipitation of the systems, and thus are less susceptible to migration. Therefore, the release and migration of elements in the acid coal-mine drainage are controlled mainly by three factors: the oxidation rate of pyrite, the medium pH value of reaction systems, and mineralogy of the country rocks.