Abstract:

Following the research idea of "waste treatment with waste",to investigate the effects of leaching temperature (50—90℃) and leaching time (5—15min) on the migration characteristics of heavy metals (Zn, Ni, Cu, Pb, Ba and Cr), the test of leaching municipal solid waste incineration bottom ash(MSWI-BA) by leachate was conducted, and leaching toxicity of the bottom slag formed after leaching was analyzed to determine the best condition. It was found that MSWI-BA captured Ni, Zn, Pb, Cr and Ba within the leachate, while Cu was released from the MSWI-BA into the leachate. With the increase of leaching temperature, except Pb and Cr, the content of heavy metals in MSWI-BA tended to increase first and then decrease. With the increase of leaching time, each heavy metal showed different changing trends due to the changes of precipitation, adsorption, complexation, precipitation dissolution and other factors. Meanwhile, based on the results of leaching concentration and leaching rate of heavy metals, the toxicity of the bottom slag formed under different treatment conditions was relatively low, with leaching temperature of 70℃ and leaching time of 10min being the optimal operating condition. This paper provided a valuable reference on heavy metal migration control during the contact of MSWI-BA and leachate in real industrial processes.

Key words: municipal solid waste incinerated bottom ash, leachate, heavy metals, migration, leaching toxicity

摘要：

遵循以废治废的研究思路，通过开展渗滤液浸沥城市生活垃圾焚烧炉渣的实验，探究了渗滤液在不同浸沥温度（50~90℃）及浸沥时间（5~15min）下对垃圾焚烧炉渣中重金属Zn、Ni、Cu、Pb、Ba和Cr迁移行为的影响，并对浸沥后形成的底渣进行浸出毒性分析，以判断最佳浸沥条件。研究发现，炉渣可捕获渗滤液内的Ni、Zn、Pb、Cr和Ba，而Cu则从炉渣内释放迁移至渗滤液内。伴随浸沥温度的升高，除Pb和Cr以外，底渣内重金属整体呈现先增加后减少的变化规律。随浸沥时间增加，各重金属由于沉淀、吸附、络合或沉淀溶解等因素变化呈现不同变化特点。根据浸沥后形成的底渣内重金属浸出浓度和浸出率分析，所有浸沥工况下形成的底渣毒性均较小，浸沥温度70℃、浸沥时间10min为最佳工况。本文通过重金属浸出毒性分析为实际工业过程中被渗滤液浸沥后炉渣二次利用提供了有价值的参考。

关键词: 生活垃圾焚烧炉渣, 渗滤液, 重金属, 迁移, 浸出毒性