垃圾衍生燃料燃烧飞灰中重金属元素的浸出机制研究

发布时间：2018-01-23 01:48

  本文关键词： 垃圾衍生燃料 飞灰 重金属 浸出机制　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着垃圾焚烧技术在国内的发展,垃圾衍生燃料(Refuse Derived Fuel,RDF)凭借燃烧充分、热值高、燃烧产物污染程度低等优势,在国内开始被广泛关注。RDF燃烧后产生的飞灰具有潜在的资源化利用前景,但是处置不当仍对环境存在一定的危害。目前,国内外对RDF飞灰的理化特性做了大量的研究,但对RDF燃烧飞灰中重金属的浸出机制研究甚少。本论文旨在研究填埋场堆积的RDF飞灰中重金属的浸出机制,为RDF飞灰的资源化利用提供参考依据。重点进行以下几方面的工作:(1)本论文以不同地区填埋场堆积的2种陈化飞灰(堆积时间半年)及2种新鲜飞灰(堆积时间一周)为研究对象,进行了不同pH值下的浸出实验,实验结果表明,两种RDF飞灰中,Cu、Zn、Cd、Cr及Pb的浸出行为均为阳离子浸出模式,随着pH值的增加浸出液中元素浸出浓度会降低;Cr的浸出行为也类似于两性浸出模式,浸出液中的元素浸出浓度在中性pH条件(pH约为7)时最低,而在酸性和碱性环境下增大。(2)采用地球化学模拟软件Visual MINTEQ模拟室温下不同pH值下重金属浸出过程,从而通过模拟结果分析比较重金属的浸出机制。结果表明:Cr及Cu属于氧化还原反应敏感型元素,Cd、Pb及Zn则属于敏感性较低或无氧化还原敏感型元素;重金属元素中 Cr、Cu、Cd、Pb 及 Zn 分别以 Cr(Ⅲ)、Cu(Ⅱ)、Cd(Ⅱ)、Pb(Ⅱ)及 Zn(Ⅱ)形态存在。(3)采用地球化学模拟软件Visual MINTEQ模拟不同温度下重金属浸出过程,从而研究温度是否对重金属的浸出行为存在影响。结果表明:不同温度下,同种重金属在陈化飞灰与新鲜飞灰中的浸出行为表现一致;温度对重金属元素Cd、Pb和Zn的浸出影响很小,而对Cr及Cu的浸出有一定的影响,在一定pH范围内,温度越高Cr及Cu重金属元素越易浸出,温度越低越不利于Cr及Cu重金属元素的浸出。本论文完成了对RDF燃烧飞灰中重金属浸出机制的研究,模拟分析了不同温度对重金属浸出行为的影响,对RDF燃烧飞灰的资源化利用具有一定参考价值。
[Abstract]:With the development of MSW incineration technology in China, the MSW derived fuel Refuse Derived fuel (RDF) has the advantages of sufficient combustion, high calorific value and low pollution degree of combustion products. In China, the fly ash produced by the combustion of .RDF has the potential prospect of resource utilization, but the improper disposal is still harmful to the environment. The physical and chemical properties of RDF fly ash have been studied extensively at home and abroad. However, the leaching mechanism of heavy metals in RDF combustion fly ash is rare. This paper aims to study the leaching mechanism of heavy metals in RDF fly ash accumulated in landfills. To provide a reference for the utilization of RDF fly ash. Focus on the following aspects of work: 1) this paper based on different landfills to accumulate two kinds of fly ash (deposition time half a year). And two kinds of fresh fly ash (the accumulation time is one week) as the research object. Leaching experiments at different pH values have been carried out. The results show that the leaching behavior of the two kinds of RDF fly ash is cationic leaching mode. With the increase of pH value, the leaching concentration of elements will decrease. The leaching behavior of Cr is similar to that of amphoteric leaching. The leaching concentration of elements in leaching solution is the lowest when pH is about 7 under neutral pH. The geochemical simulation software Visual MINTEQ was used to simulate the leaching process of heavy metals at different pH values at room temperature. The leaching mechanism of heavy metals was analyzed and compared by the simulation results. The results showed that: cr and Cu belong to the redox sensitive elements (CD). Pb and Zn belong to less sensitive or non-oxidation-reduction sensitive elements. In the heavy metal elements, Cr (鈪，

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