【作者】 金剑；

【导师】 严建华； 李晓东； 池涌；

【作者基本信息】 浙江大学 ， 能源环境工程， 2010， 博士

【摘要】 本文利用水热法来处理垃圾焚烧飞灰和重金属废水,实验研究了水热法稳定重金属的机理,水热条件对于稳定化效果的影响。利用XRD分析仪、SEM-EDS、ICP-MS和BET氮吸附仪等仪器对等水热反应后飞灰与废水的特性,如元素含量、表面形态、比表面积、重金属浓度、渗滤毒性进行实验研究。利用能谱仪SEM-EDS和XRD分析了典型生活垃圾焚烧厂和医疗废物焚烧厂的垃圾焚烧飞灰的元素组成特性,表面形态和晶相结构特性,并利用国家环保部制定实行的固体颗粒物重金属渗滤毒性测试标准研究了飞灰的重金属浸出特性,实验中各种重金属的浸出浓度各异,Zn的浸出浓度最大,而作为毒性较大的重金属Pb和Cd的浸出值超出了标准值。飞灰水热稳定化处理实验中,发现Al,Si元素含量、反应温度和反应时间的提高对重金属稳定化效果起促进作用,最终趋于平稳；而液固比、碱性物质添加量、废水初始重金属浓度对于重金属稳定化效果的影响具有波动性,通过实验研究得出,水热反应时液固比和碳酸钠投加量对处理效果和二次污染均有较大的影响。结果表明,液固比为10/1,碳酸钠投加量(以20g干灰质量计)为4-5 g较为合理。飞灰与废水重金属同步去除稳定化处理实验中,在水热过程中,NaOH的添加有助于硅铝酸盐的形成,并且提高反应温度有助于硅铝酸盐结晶率的提高。MWI飞灰对重金属的去除效果受到反应温度,NaOH添加量与初始重金属浓度的影响。去除效率随着反应温度和初始浓度的升高而升高,但是过量添加NaOH会导致Zn(Ⅱ)和Pb(Ⅱ)去除效率的急剧下降。在水热过程中,重金属不但从废水中去除,而且进一步转化为稳定的矿物结构稳定于飞灰中。渗滤毒性测试结果显示,水热处理后飞灰渗滤毒性大大降低。而反应后飞灰的渗滤毒性也受到反应条件的影响。较高的反应温度以及合理的NaOH添加量,适中的重金属废水浓度可以使反应后飞灰重金属渗滤毒性以及出水重金属浓度处于极低的水平。在水热过程中同时伴随着二噁英类有机污染物的脱氯效应,在重金属稳定化的同时,飞灰中二嗯英浓度也得到大大降低。通过本文的研究,形成了垃圾焚烧飞灰与废水中重金属以及飞灰中二噁英类有机污染物的较为经济有效处理工艺,为实现城市生活垃圾及医疗废物焚烧法的污染“零排放”技术做了有效的补充。更多还原

【Abstract】 In this context, the hydrothermal process has been applied to deal with heavy metals from both waste incineration fly ash and waste water. Experimental studies of the hydrothermal synthesis and stabilization mechanism of heavy metals, and the stabilization effect of hydrothermal conditions have been determined. XRD analyzer, SEM-EDS, ICP-MS, the BET nitrogen adsorption instrument and other equipment applied to discover the effects of hydrothermal treatments on treated fly ash and wastewater characteristics, such as the element content, surface morphology, specific surface area, and heavy metal concentration of leachate.Fly ash used in experiments from municipal solid waste incineration and medical waste incineration was investigated experimentally, using the SEM-EDS and XRD to analyze the characteristics of their elemental composition, surface morphology and crystalline structure characteristics, and take advantage of solid particulate matter standards for heavy metals leaching toxicity formulated and implemented by the State Environmental Protection Department to identify the heavy metal leaching characteristics of fly ash. Among various concentrations of different heavy metals, Zn leaching concentration is the greatest, but as a highly toxic heavy metals, Pb and Cd leaching concentration have exceed the standard value.The increasing Al, Si element contents, reaction temperature and reaction time have been found play a positive role Fly ash treatment hydrothermal stability experiments and found that, increase the effects of heavy metals in stabilization and eventually stabilized. While the effects of liquid-solid ratio, dosage of alkaline substances, and initial concentrations of heavy metals in wastewater for the stabilization of heavy metals are volatile. Emerging from the study through experiments, liquid-solid ratio and dosage of sodium carbonate treatment have a greater impact on stabilized effect and secondary pollution. The results showed that, liquid-solid ratio of 10/1, sodium carbonate dosage (to 20 g dry mass of ash) for 4-5 g is more reasonable.In heavy metals co-disposal hydrothermal process, NaOH additions contribute to the formation of aluminosilicate, and the increasing reaction temperature helps to increase the crystals rate of aluminosilicate. The heavy metals removal efficiency of MWI fly ash affects by the reaction temperature, NaOH dosage and the initial heavy metal concentration. Removal efficiency increased with the reaction temperature and higher initial concentration, but too much addition of NaOH will lead to Zn (II) and Pb (II) removal efficiency dropped drastically.In the hydrothermal process, heavy metals were not only removed from the wastewater, and further transformed into a stable mineral structure and stability in the fly ash. Leaching toxicity test results showed that heavy metals leachability of fly ash greatly reduced as the effect of hydrothermal reaction. The reaction conditions have also affect heavy metals leachability of treated fly ash. Higher reaction temperature and a reasonable amount of NaOH addition, moderate concentrations of heavy metals in waste water can make lower heavy metals leachability of treated fly ash.Via the study of this paper, a relatively cost-effective treatment process for dealing with the waste incineration fly ash, heavy metals containing waste water and dioxins in fly ash, and has done an effective supplement for the realization of municipal solid waste and medical waste incineration pollution "zero emission" technology.更多还原