熔融条件下飞灰中Zn与Pb的挥发行为及其影响因素  

Vaporization Behaviors of Zn and Pb in Fly Ash and the Effects of Influential Factors in Smelting Process

作　　者：付中华[1] 张延玲[1] 王玉刚[1] 李士琦[1] 

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083

出　　处：《过程工程学报》2009年第S1期473-481,共9页The Chinese Journal of Process Engineering

基　　金：国家自然科学基金资助项目(编号:50704004)

摘　　要：对4种飞灰处理工艺进行对比,并综述了关于熔融处理条件下飞灰中Zn,Pb等重金属挥发行为的主要研究成果.首先讨论了Zn,Pb挥发的相关热力学,动力学行为,包括饱和蒸汽压,挥发物种类,最大挥发率及挥发速率等.其次阐述了温度,Cl,H2O,碱金属,Al2O3等基体成分以及系统气氛对Zn,Pb稳定存在的化合物种类,挥发速率,以及最大挥发率的影响趋势及其机理,其中温度是决定性因素;Cl含量较高和还原气氛条件下能够促使Zn,Pb形成挥发性较强的单质和氯化物,对二者的挥发有促进作用;而H2O,碱金属,酸性氧化物如Al2O3等及氧化气氛下Zn,Pb易生成难挥发的氧化物和复杂化合物,而滞留于渣相中.最后指出,熔融处理飞灰过程中形成的是多元熔渣/熔盐体系,关于重金属Zn,Pb在这类体系中的饱和蒸汽压,活度等基本热力学数据较为有限,尚需要大量的研究工作.Four kinds of treatment of fly ash were compared in this paper. Some previous researches on the vaporization behaviors of Zn and Pb in fly ash and the effects of influential factors in smelting process were reviewed. Firstly, the related thermodynamic and kinetic information was discussed, including saturated vapor pressure, vapor species, maximum degree of evaporation and vaporization rate. Then, the effects of temperature, Cl, H2O, alkali metals, atmosphere, and matrix compositions such as Al2O3 and SiO2 on stable vapor species, vaporization rate, and the maximum degree of vaporization were expatiated, together with the influential mechanism. Temperature is a crucial factor that greatly influences their vaporization. Metallic Zn, Pb and their chlorides may form in the conditions of high Cl potential or reductive atmosphere, which promotes their vaporization. In a system with high content of H2O, or alkali metals such as Na and K, the formation of Zn and Pb chlorides may be prohibited because of a stronger affinity between H, Na or K with Cl, their vaporization is limited. The complicated compounds of Zn, Pb such as Zn2SiO4 easily form under oxidizing atmosphere, which tends to make Zn, Pb stay in the residues. Finally, it is pointed out that the basic data, such as saturated vapor pressure and activities of zinc and lead in molten slag/salt, are very limited, therefore it is necessary to carry out such kind of research in the future study.

关 键 词：飞灰 重金属 熔融处理 挥发行为 影响因素 

分 类 号：X705[环境科学与工程—环境工程]