不同年代废弃的铅锌矿渣堆中重金属的动态变化

Dynamic of Heavy Metals in a Lead-Zinc Tailings Deposited in Different Years

分别调查了堆积时间在10、20和近100a的铅锌矿渣堆,埋深在10、30、60cm的重金属含量变化情况。结果表明,由于雨水的淋溶作用和酸化,矿渣堆表层的重金属随堆积时间延长而减少,在100a的矿渣堆中,表层的铅含量仅有575.51mg·kg-1,但下层含量却达到5144.57mg·kg-1。在这些矿渣堆中,可溶性铅的含量也较高,最高达到了453.48mg·kg-1,而堆积20a和10a的矿渣中表层的重金属含量减少的程度较小,可溶性铅含量也相对小,最高含量分别为197.1mg·kg-1和50.11mg·kg-1。在堆积初期,表层的可溶态重金属含量较高,随时间的推移,下层含量逐渐增加,在某一个历史时期超过上层。

Losses of several heavy metals at dep ths of 10,30and 60cm in a lead -zinc ta ilings deposited about 10,20and 100years,respectively,were evaluate d.Due to raining -water and acidific ation,in case of the tailings deposited about 100years(100-year tailing),the largest loss of the metals(575.51mg ·kg -1 at 10centimeter to 5144.57mg ·kg -1 at 60centimeter)and the highest soluble metals(453.48mg ·kg -1 at 60centimeter)were observed.In contrast,the tota l heavy metals of surface of 20-year and 10-year tailings have been l ost lightly;while the soluble metals were also low,withthe highestvalu e of197.1mg ·kg -1 and50.11mg ·kg -1 ,respectively.In younger tailings,the soluble metals of surface were higher than that of the deeper layers,but it was opposite in the 100-year tailing,fr om 10,30,to 60cm depth,the soluble metals increased.