垃圾焚烧过程中多种重金属资源化回收的研究

项目名称： 垃圾焚烧过程中多种重金属资源化回收的研究

项目编号： No.50806053

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 化学工业

项目作者： 韩军

作者单位： 武汉科技大学

项目金额： 21万元

中文摘要： 近年来，垃圾焚烧产生的重金属污染受到人们广泛的关注。传统的研究思路是将重金属固化于底灰中而避免蒸发，进而减少重金属排放。即使经过上述处理，焚烧飞灰中重金属浓度还是相当高，因此被认为有毒危险物质而必须进行二次处理后才能填埋。本项目首先研究了重金属在垃圾或污泥中的形态，分析了其析出与垃圾或污泥焚烧的关系。接着，借助计算流体动力学，分析了重金属气固转变的方式，结果显示85-90%的PbCl2气固转化归因于冷凝过程，5～10％是由于结核过程。总所周知，重金属化合物的熔沸点不同，其气固转变温度也不同，因此可通过在不同温度分级捕获飞灰以实现重金属的分离，飞灰中Pb质量分数可以达到34%，Cu的质量分数可以达到6%。最后，通过加硫酸和氢氧化钠洗涤的方式，可将上一步获得的飞灰中Pb和Zn回收，Pb最大回收效率可达85.9%。

中文关键词： 垃圾；焚烧；重金属；分离；回收

英文摘要： In recent years, heavy metals from waste incinerator have attracted more attentions.The conventional method for controlling heavy metals is stablizing heavy metals in sluge or reducing the vaporization of heavy metals during waste incineration. However,the concentration of heavy metals in fly ash is relatively high even the conventional method of reducing heavy metals is applied. The project aims to recycle or reuse heavy metals in fly ash from waste incinerator. First,the occurrence of heavy and alkali metals in waste was analyzed. At the same time, the vaporization characteristic of heavy and alkali metals during waste incineration were also considered.Then, CFD was used to analysis the gas-solid transformation in the downstream of incinerator, the experimental results showed that 85-90% PbCl2 was attributed by condensation, the contribution of nucleation is only 5-10%. As we know,each compound has its melting and boiling point, the separation of heavy metals can be achieved by capturing fly ash at different zone. The fraction of Pb in fly ash can reach 34%,and 6% Cu is enriched in fly ash. After acid/ alkaline leaching, the recycle or reuse of heavy metals is feasibility.The experimental results showed the maximum recycle efficiency of Pb is about 85.9%.

英文关键词： Waste;Incineration; Heavy metals; Separation; Recycle