攀枝花地区煤矸石中重金属元素浸出行为

Leaching Behavior of Main Heavy Metal from Coal Gangue in Panzhihua Region

针对煤矸石中重金属元素污染问题,对攀枝花地区煤矸石开展了分批静态浸出实验。结果表明,该区煤矸石浸出的重金属元素主要为Fe、Zn、Mn和Cu,Co、Cr、Pb和Ti的浸出量不大,As、Ni则难以浸出。浸提液pH值、环境温度和液固比对浸提液中Co、Cr、Cu、Fe、Pb和Ti的浸出浓度影响显著,低pH值、高温和高液固比有利于Co、Cr、Cu、Fe、Pb和Ti的浸出。对于Mn和Zn,pH值和液固比是影响其浸出的主要环境因素,温度的影响效果并不显著,低pH值和高液固比可促进Mn和Zn的浸出。细粒径煤矸石中大部分金属(Co、Cu、Mn、Ni、Pb、Ti和Zn)的浸出浓度更高,但占比小;-5+2 mm粒径的煤矸石占比高,且其中的各金属的浸出浓度均较高;煤矸石中大部分金属(Co、Cr、Cu、Fe、Mn和Zn)的释放持续时间较长,但长时间的浸出会使Cu、Fe的浸出浓度下降。

In order to study the releasing mechanism and the environmental effect of heavy metals in the coal gangue of Panzhihua,the metal leaching experiments were carried out under the conditions of pH value,ambient temperature,liquid-solid ratio,time and particle size.Results showed that the leaching concentration of Co,Cr,Cu,Fe,Pb and Ti were significantly affected by pH,ambient temperature and liquid-solid ratio of the extract,and low pH,high temperature and high liquid-solid ratio were favorable for the leaching of Co、Cr、Cu、Fe、Pb and Ti.Leaching concentration of Mn and Zn were significantly affected by pH and liquidsolid ratio of the extract,but not obviously by ambient temperature.Leaching concentration of thin samples was higher than that of thick ones,but the proportion of thin ones was low.Proportion of-5+2 mm particles was high,and their leaching concentration were high.Most metals in coal gangue(Co、Cr、Cu、Fe、Mn and Zn)have a long release duration,but the leaching concentration was declining with time increasing.