不同渗滤条件下垃圾焚烧飞灰中重金属的渗滤特性

Leaching Characteristics of Heavy Metals in MSW Fly Ash Under Different Condition

对垃圾焚烧飞灰在酸性及碱性条件下的渗滤特性进行了实验研究 ,结果表明 ,重金属Pb、Zn、Ni、Cr及Hg存在相似的渗滤规律 ,即在酸性及碱性 (pH >1 2 )条件下均有一定的渗滤 ,且渗滤量随着渗滤液浓度及液固比 (L/S)的增加而增加 ,如对于Pb在酸、碱 2种渗滤环境下 ,当液固比由 2 0增加到 4 0时 ,渗出量分别由 0 4 5 7mg/kg、5 1 1 4 2mg/kg增加到 1 0 4 5 76mg/kg、5 9 6 92mg/kg .而Cd、Cu只在酸性环境下存在渗滤情况 ,在碱性环境下几乎没有渗滤 ,在酸性环境下对于所研究的几种重金属 ,Cd、Pb、Zn的渗出率较高 。

The leaching characteristic of heavy metals in MSW fly ash was studied under acidic and alkaline condition. The result showed the leaching characteristic of Pb, Zn, Ni, Cr and Hg had similar law, which was these heavy metals could leach out under acidic condition and alkaline condition(pH>12), and the leaching amount increased with the leachate density or L/S increasing. For example, under acidic and alkaline condition, the leaching amount of Pb increased from 0 457 mg/kg, 51 142 mg/kg to 104 576 mg/kg, 59 692 mg/kg respectively when L/S increased from 20 to 40 Cd and Cu could leaching out only under acidic condition. Under acidic condition the leaching rate of Cd, Pb and Zn were higher then the others.