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

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.