利用垃圾焚烧炉内循环处理垃圾焚烧飞灰的技术研究

将垃圾焚烧厂的垃圾焚烧飞灰作为球核主料和含碳还原剂以及必要的吸氯剂和催化剂制成复合球团,投入到垃圾焚烧炉进行高温还原分解二噁英,重金属形成玻璃态熔渣。从而对垃圾焚烧飞灰进行无害化处理,实现了垃圾焚烧飞灰在焚烧炉自身完整的闭路内循环处置,为处理垃圾焚烧飞灰提供了最佳技术路线。     

垃圾焚烧飞灰中二噁英污染控制技术研究进展

垃圾焚烧发电技术凭借多项优势正成为我国大多数城市处理垃圾的首要选择。而焚烧飞灰作为垃圾焚烧的副产物之一，由于富集重金属和二噁英(PCDD/Fs)等被划定为危险废物，规定在其最终处置前需要进行无害化处理。在垃圾焚烧飞灰无害化处理前，对其中的PCDD/Fs进行减量和降解是十分必要的。因此，本文对焚烧飞灰中PCDD/Fs的污染控制技术(包括源头控制、过程控制和末端控制)进行了综述，针对焚烧过程飞灰PCDD/Fs的高温气相反应和低温多相反应(从头合成、前体催化合成)，以及末端控制方法中的催化还原、热处理、光催化、机械化学处理和水热处理等技术的最新研究进展进行了介绍，并讨论了不同处理技术的特点、挑战和未来的发展方向，为焚烧飞灰中PCDD/Fs的污染控制技术发展提供参考。     

城市生活垃圾焚烧飞灰中重金属的固化/稳定化处理

城市生活垃圾焚烧飞灰已被明确规定为危险废物,其中含有的大量有毒重金属对自然环境和人类生存会造成严重危害.综述了目前常用的水泥固化、烧结固化、熔融固化、药剂稳定化四种固化/稳定化垃圾焚烧飞灰中有毒重金属的方法,对比分析了各项技术的优缺点;对城市生活垃圾焚烧飞灰中重金属固化/稳定化处理的发展前景进行了展望,指出资源化利用是未来发展的必然趋势.     

利用垃圾焚烧飞灰固化污染底泥的实验研究

为探讨利用垃圾焚烧飞灰代替水泥进行污染底泥固化的可行性,研究了不同配比的底泥、水泥、垃圾焚烧飞灰的固化体抗压强度及浸出毒性.结果表明：固化剂中用20%的垃圾焚烧飞灰替代10%的水泥配置的固化体7.d,其抗压强度可达0.24.MPa,重金属浸出浓度低于毒性标准,固化体可进入固废填埋场填埋处置.     

茶皂素稳定和改性处理垃圾焚烧飞灰试验研究

以上海市生活垃圾焚烧飞灰的高附加值资源化和稳定化为目标,初步研究茶皂素对城市生活垃圾焚烧飞灰改性活化以及对重金属离子的螯合效果,改性飞灰的活化指数可达95%以上.在试验的同时,比较了茶皂素、EDTA,硫脲和磷酸钠对飞灰中重金属的稳定螯合效果.经重金属毒性浸出试验表明,茶皂素对飞灰中的重金属具有较强的束缚能力,其稳定化效果与硫脲和磷酸钠螯合剂能力相当.     

我国固体废物处理与资源化展望

文章比较全面地分析了我国当前在固体废物方面急需解决的问题，如垃圾焚烧厂飞灰、医疗垃圾、废汽车和废家电等。总而言之，我国在环境保护技术方面与发达国家至少相差２０～３０年。城市生活垃圾和危险废物等仍未得到适当处理。     

我国固体废物处理与资源化展望

文章比较全面地分析了我国当前在固体放心物方面急需解决的问题，如垃圾焚烧厂飞灰，医疗垃圾，废汽车和废家电等。总而言之，我国在环境保护技术方面与发达国家至少相差20－30年。城市生活垃圾和危险废物等仍未得到适当处理。     

水热法稳定垃圾焚烧飞灰重金属研究

水热法是生活垃圾焚烧飞灰无害化处置新方法,在飞灰重金属稳定化方面具有显著能力.在前期研究基础上,提出利用水热法耦合化学添加剂方法实现重金属的深度稳定化,设计正交实验研究各参数对重金属浸出毒性的影响.结果表明:实验的较优工况为以空气为气氛,碳酸钠为添加剂,在300℃下水热并保持1h;同时可通过增大添加剂使用量来降低飞灰的浸出毒性,达到生活垃圾填埋场的飞灰进场标准.水热法可有效改变飞灰微观结构,降低颗粒粒径;水热后重金属是以一种稳定的、难以离子交换的形式存在,从而实现稳定化;水热反应中有部分微、中孔向大孔转变,改善了孔隙结构,具有更大的比表面积,飞灰利用价值也得到了提升.     

城市垃圾焚烧飞灰熔融动力学研究

在高温差示扫描量热差热分析（DSC-DTA）实验基础上，对垃圾焚烧飞类熔融过程进行研究，建立飞灰熔融动力学模型，在惰性气氛（N2）和氧化气氛（O2）下，20-1450℃的温度对两种垃圾焚烧飞灰的熔融过程进行研究，实验采用了三种温升速率（5、10、20℃/min），并研究了CaO添加剂对飞灰熔融的影响。飞灰熔融过程包含干燥脱水、多晶转变和熔融相变三种反应，脱水发生在100-200℃，多晶转变发生在480-670℃，熔融发生在1136-1231℃，在1174℃达到峰值，提出了垃圾焚烧飞灰熔融的0级反应动力学，并得到飞灰熔融反应表现活化能。     

杭州地区生活垃圾焚烧飞灰基本特性分析

对杭州两种典型生活垃圾焚烧工艺产生的飞灰A(炉排炉)和飞灰B(流化床)进行物化性质、自身胶结强度、土工性质和重金属总量及浸出毒性测试,并与其他地区的飞灰研究结果进行对比分析,为飞灰无害化处置提供技术支持。结果表明:飞灰A和飞灰B颗粒表面均疏松多孔,且均含有较多的CaO及一定量的Al2O3、SiO2和Fe2O3,自身胶结后无侧限抗压强度(灰水比为1kg∶300mL)分别为0.281MPa和0.283MPa。根据颗粒级配和液塑限测试结果,飞灰A属于粉土类,飞灰B属于黏土类。飞灰A和飞灰B的比重分别为2.463和2.858。飞灰A和飞灰B的孔隙比分别为2.81和2.68,相应的渗透系数分别为5.211×10-7 cm/s和2.069×10-8 cm/s。飞灰A中重金属总量约占飞灰质量的0.71%,其中Cu、Zn和Pb分别为杭州土壤背景值的48、60和63倍;飞灰B中重金属总量约占飞灰质量的1.26%,其中Cu、Zn和Pb分别为杭州土壤背景值的77、123和65倍。根据重金属浸出毒性测试结果,两种飞灰均不满足危险废物填埋场直接入场填埋要求,必须进行安全处置后方可进行填埋或资源化利用。     

Effect of MSWI fly ash and incineration residues on cement performances

The activities of municipal solid waste incineration (MSWI) fly ash and incineration residues were studied contrastively, through the component analysis and the activity ratio tests. The mechanical properties, hydration mechanism and leaching toxicity of the hardened cement paste mixing with MSWI fly ash and incineration residues were investigated. The experimental results indicated that the active constituents (CaO+Al₂O₃+Fe₂O₃) in MSWI fly ash were higher than those in incineration residues. Therefore the activity ratio of MSWI fly ash was 43.58%, twice as much as that of incineration residues. Meanwhile, the hydration of cement was delayed by mixing with MSWI fly ash and incineration residues, which also reduced the cement strength markedly. By adding with exceeding 20% MSWI fly ash, the specimens expanded and microcracks appeared. The leaching toxicities of cement pasted mixed with MSWI fly ash and incineration residues were lower than the Chinese national standard. Accordingly the cement mixed by MSWI fly ash and incineration residues can be considered as the environment-friendly materials.     

配料对焚烧飞灰电弧炉熔渣晶化行为的影响

将垃圾焚烧飞灰电弧炉熔融处理后的液态熔渣直接浇铸成型后热处理,运用同步热分析仪、X射线衍射仪和扫描电镜等方法,研究废玻璃和晶核剂(TiO2和Cr2O3)等辅助原料的添加对微晶玻璃晶化行为及性能影响.研究表明,适量掺加废玻璃对微晶玻璃理化性能有显著改善,晶核剂类型及添加比对微晶玻璃主晶相和晶化程度影响较大,微晶玻璃的理想原料配比为m(废玻璃)∶m(垃圾焚烧飞灰)=1∶1,晶核剂TiO2添加质量分数为3%,制成的微晶玻璃主晶相为透辉石Ca(Mg,Al)(Si,Al)2O6和少量普通辉石Ca(Mg,Fe,Al)(Si,Al)2O6,抗弯强度54.96 MPa,主要理化性能达到或优于天然花岗岩和大理石,重金属浸出浓度低于国际建材环保要求限值.     

Effect of MSWI Fly Ash and Incineration Residues on Cement Performances

The activities of municipal solid waste incineration (MSWI) fly ash and incineration residues were studied contrastively, through the component analysis and the activity ratio tests. The mechanical properties, hydration mechanism and leaching toxicity of the hardened cement paste mixing with MSWI fly ash and incineration residues were investigated. The experimental results indicated that the active constituents (CaO+Al2O3+Fe2O3) in MSWI fly ash were higher than those in incineration residues. Therefore the ...     

Physicochemical properties and heavy metals leachability of fly ash from coal-fired power plant

The physicochemical properties of fly ash from two kinds of coal-fired power plants were studied. Three aspects were examined: the micro-morphology, the mineral composition and the content of heavy metals. The results show that the fly ash from plants using a circulating fluidized bed are more irregular particles, while the particles from the plants using a pulverized coal-fired boiler are mainly spherical in shape. Quartz and mullite are the main crystalline phases in the ash. Clearly, both the technology and the coal used by a power plant can influence the mineral composition of the ash. The mineral composition of fly ash from a circulating fluidized bed is more complex than that from a pulverized coal-fired boiler. The quantity of elements found in the fly ash is greater than that found in the bottom ash for the same plant. Heavy metals are likely to be enriched in the fly ash. Heavy metal leachability was studied using two leaching methods. The results indicate that most of the heavy metals that leached during either batch leaching or column leaching experiments did not exceed the related maximum concentration standards. But Ni concentrations in the leachates from both batch and column tests exceed the standard. The highest excess rates in both tests were 572% and 497%, which levels might threaten the environment.     

逆向涡流等离子体降解飞灰中二恶英的研究

利用氮气逆向涡流非平衡等离子体反应器,进行医疗垃圾焚烧飞灰中二恶英的降解.考察氮气逆向涡流非平衡等离子体放电特性,从而获得反应器稳定的工作条件.在实验过程中分别测量处理后飞灰中和尾气中的二恶英质量分数,分析利用氮气逆向涡流非平衡等离子体反应器降解飞灰中二恶英的效果,初步探索二恶英的降解机理.结果表明,切向进气体积流量是影响放电电弧特性的关键因素,增大切向进气体积流量,可以提高电弧放电的稳定性;逆向涡流等离子体对飞灰中二恶英有明确的降解作用,单位质量飞灰中PCDD/Fs总质量的平均降解率为49.6%,总毒性当量I-TEQ平均降解率为62.3%,飞灰中PCDFs比PCDDs更容易降解.     

Microstructures and thermal properties of municipal solid waste incineration fly ash

To analyze the feasibility of utilization of thermal technology in fly ash treatment, thermal properties and microstructures of municipal solid waste incineration (MSWI) fly ash were studied by measuring the chemical element composition, specific surface area, pore sizes, functional groups, TEM image, mineralogy and DSC-TG curves of raw and sintered fly ash specimens. The results show that MSWI fly ash particles mostly have irregular shapes and non-typical pore structure, and the supersonic treatment improves the pore structure; MSWI fly ash consists of such crystals as SiO₂, CaSO₄ and silica-aluminates, and some soluble salts like KCl and NaCl. During the sintering process, mineralogy changes largely and novel solid solutions are produced gradually with the rise of temperature. Therefore, the utilization of a proper thermal technology not only destructs those persistent organic toxicants but also stabilizes hazardous heavy metals in MSWI fly ash.     

医疗废物焚烧灰、渣对人体健康风险评价

针对医疗废物处置不当容易产生二次污染的的问题,指出焚烧法是目前最为可行的处置方法之一,但处置医疗废物产生的固体废弃物(飞灰、灰渣)若直接释放到环境中,仍可能存在潜在的环境风险与危害.通过浸出实验与模式预测相结合,研究飞灰与灰渣中重金属通过饮水途径对人体产生的健康风险值.铬在医疗飞灰和灰渣中个人年风险最大,分别达8.8865×10-5/a和8.2597×10-5/a,超过国际辐射防护委员会(ICR)推荐的最大可接受风险5.0×10-5/a.医疗废物焚烧处置后的飞灰、灰渣存在着健康风险隐患,应该对其按危险废物进行处置与环境管理.     

The Cement Solidification of Municipal Solid Waste Incineration Fly Ash

The chemical composition, the content and the leachability of heavy metals in municipal solid waste incineration （ MSWI） fly ash were tested and analyzed. It is shown that the leachability of Pb and Cr exceeds the leaching toxicity standard, and so the MSWI fly ash is considered as hazardous waste and must be solidifled. The effect of solidifying the MSWI fly ash by cement was studied, and it is indicated that the heavy metals can be well immobilized if the mass fraction of the fly ash is appropriate. The heavy metals were immobilized within cement hydration products through either physical fixation, substhtaion, deposition or adsorption mechanisms.