【作者】 池冬华；

【导师】 刘振鸿；

【作者基本信息】 东华大学 ， 环境工程， 2004， 硕士

【摘要】 垃圾焚烧飞灰是全世界公认的危险废物，主要原因是：飞灰中含有大量能被水浸出的重金属、盐类，另外飞灰中的有机污染物质也是不可忽视的问题。飞灰的处理的主要思想一是借助固化／稳定化的作用来控制污染物在环境中的迁移；二是对飞灰中的污染物质进行分离从而降低飞灰中污染物的含量。飞灰处理的主要目标是降低甚至消除飞灰的毒性。目前国内垃圾焚烧厂对于飞灰的处理大部分是直接填埋，对飞灰采用固化稳定化处理确实不多。 本课题针对飞灰中重金属的稳定，采用水泥为固化剂，对固化稳定化垃圾焚烧飞灰做了大量的试验研究，且对飞灰固化前和固化后的特性做了分析。本课题中采用的飞灰是在上海浦东垃圾焚烧厂袋式除尘器取得，试验对飞灰进行了元素组成分析、X射线衍射分析、浸出毒性测试以及飞灰水洗酸洗后重金属的浸出毒性等进行了分析，了解其性能后对飞灰进行了水泥固化处理，探讨不同的飞灰／水泥配比下的水泥固化体的浸出毒性、固化体的抗压强度、固化体中物相变化X射线衍射分析以及水泥固化稳定化水洗飞灰的浸出毒性测试和抗压强度测定，并进行了经济评估。 飞灰在水泥固化前性能研究，试验表明飞灰浸出液中锌、铅、镉的浓度高于固体废物浸出毒性鉴别标准，也正是因为这一点，飞灰被普遍认为是一种危险废物，必须对之进行稳定化处理。采用普通425#硅酸盐水泥，固化稳定化飞灰中的重金属，从固化效果及重金属的浸出毒性实验发现其固化体中原料最佳配比为飞灰:水泥=2:1。 水泥固化法最终形成的固化块，不论是自然堆存或是作为路基再利用，都应具有足够的抗压强度，否则会出现破裂和散裂，从而增加暴露的表面积和污染环境的可能性。不同飞灰／水泥配比的水泥固化体的抗压强度测试表明，随着飞灰加入量的增加，固化体的抗压强度降低，但最终达到的强度还是能够满足建筑用途或填埋的强度要求。固化体强度的降低是由于水泥固化体中水化产物的减少，而水化产物的判别，则是X射线衍射分析(XRD)一个重要方面。 水泥固化存在长期稳定性和体积增大的问题，针对水泥固化的不足，采用飞灰经过水洗预处理后再固化稳定化于水泥结构中以及采用化学稳定剂来改 变飞灰中重金属的存在形式。 飞灰经过水洗后质量减少40%，除去大部分的可溶性盐和部分水溶性且延 缓固化时间的物质(如，硫酸盐、氯化物、碱和重金属)。水洗飞灰在混合物 中可以达到重量百分比为75%一90%，而不会有重金属从固化体中浸出。并且 对原始飞灰水泥固化工序和水洗飞灰水泥固化工序进行了经济评估，发现后者 有更好的经济效益。 飞灰的化学稳定化正处于研究和开发阶段，本文中采用的NaOH和EDTA 来对飞灰进行稳定化处理，把重金属由固相浸取到液相中从而降低飞灰中的重 金属含量。实验结果表明，从经济性和处理效果考虑，NaOH溶液不适合用来 处理垃圾焚烧飞灰，EDTA稳定效果较好，生成的鳌合物非常稳定，很难通过一般 的方法去除或再生，造成水体污染。 未来飞灰处理的发展趋势是水泥固化和化学药剂稳定化处理结合起来，取长补短这样处理效果更好，但这样会使处理费用明显提高，因此有必要大力开发既经济又安全的新技术。更多还原

【Abstract】 Disposal of municipal solid waste has become a major problem in many countries around the world. With the benefits of substantial weight and volume reduction and potential energy recovery, incineration has become a promising municipal solid waste(MSW) management option. Despite the fact that incineration reduces volume and mass of the wastes by as much as 80%, there are still residues to be properly managed.The municipal solid waste has been recognized as the hazardous waste. The main reasons are that there are large amount of soluble heavy metals, salts and organic contaminative matter in fly ash.This research is aimed at solidification/stabilization of heavy metals in MSEI fly ash. Effective solidification of fly ash is researched by using cement as solidification agents. The fly ash generated from the incineration of waste and collected by the baghouse precipitator is considered hazardous and should be properly treated.In this thesis, the characterization of MSWI fly ash involved chemical and physical analyses, observation under X-ray Diffraction (XRD) analyses, Toxicity Characteristic Leaching Procedure (TCLP) tests. The washing of FA with acid or other reagents are studied, aiming to find a proper leaching agent for the detoxification of FA based on its leaching behaviors of the FA. The results of the tests show that the optimal condition is using NaOAc as the leaching agent with the content of 0.375mol/l, the initial pH of 3, the Liquid and solid ratio of 40 and leaching time of 60min.The thesis explores mechanism of cement solidification, evaluating the leachingtoxicity of condensates, the compressive strengths of mortar specimens, crystal varieties analyzed by X-ray Diffraction (XRD).The further improvement is that the MSWI fly ash pretreated by water is solidified/stabilified in cement mortars. Results show that the performance of fly ash is unproved considerably by removing large amount of sodium salts and Potassium salts etc, utilizing more fly ash to replace cement in mortars without influencing the condensate performance. Economic evaluation finds that the washing fly ash solidified in cement is a effective method with good economic benefits.The .benefits of using MSWI fly ash in cement mortar are twofold; namely, the cost savings stemming from reduction in cement used, and the ecological advantage of ensuring a final destination for the ash.The future trend of the treatment of fly ash is that the cement solidification and Chemical stabilization combined to obtain a good effect.Chi Donghua (Environment Engineering) Supervised by: Liu Zhenhong更多还原