垃圾焚烧飞灰中重金属的浸出规律

测定了垃圾焚烧飞灰中Zn、Pb、Cu、Cr、Ni的浸出率与pH值的关系,并利用MINTEQA2模型进行了浸出规律模拟。结果表明:Pb、Cu、Zn、Cr、Ni的模拟浸出值与实测浸出值基本吻合,模拟浸出值可反映实际浸出情况;pH2时,Zn、Cu、Pb的浸出率较大,8pH12时浸出率接近0;Zn、Pb的浸出率分别在pH7、pH2时达到最大值,最大值分别约为75%及72%,pH值12时随pH值的增加,其浸出率逐渐增强;Cr在pH4时浸出率较大,最大浸出率达43%,4pH12时浸出率接近零,pH12时其浸出率再次增加;Ni的浸出率在pH2时随pH值的增加而降低,2pH13时其浸出率接近零。

Leaching Behavior of Heavy Metals from MSWI Fly Ash

Leaching behavior of Zn, Pb, Cu, Cr and Ni as a function of pH was analyzed based on the leaching ratios at different pH derived from measurement and MinTEQA2 modeling. It was found that measured leaching ratios were essentially consistent with those derived from MinTEQA2 modeling, indicating that the latter could represent actual leaching behavior. Leaching ratios of Zn, Cu and Pb were relatively high when pH was less than 2, and stood close to zero at pH between 8 and 12. Leaching ratios of Zn and Pb reached peak value of 75% and 72% at pH less than 7 and 2 respectively, and rose with the increase of pH over 12. Leaching ratios of Cr, with the peak value registering 43% at pH less than 4, were close to zero at pH between 4 and 12, and increased again at pH exceeding 12. Leaching ratios of Ni decreased with increase of pH from 0 to 2, and stood close to zero at pH spanning 2 and 13.