垃圾焚烧飞灰热处理过程中Zn的挥发机理研究

试验在650~1350℃条件下探讨了温度和时间对飞灰中Zn的挥发率的影响，采用XAFs对飞灰及二次飞灰中Zn的赋存形态进行分析，运用吉布斯自由能理论推导了Zn的氯化反应途径，并开展了验证试验.结果表明：温度是影响Zn挥发的主要因素，其挥发趋势随温度先增加而后降低，在1000℃时挥发率达到最高，而时间对其挥发效果影响较小；Zn主要以氯化物形态挥发，从假设反应途径的吉布斯自由能理论计算及验证试验得出，热处理过程中Zn的氯化反应分两步进行，首先飞灰中氯化物与SiO₂反应生成Cl₂，而后与ZnO反应生成ZnCl₂，而小部分Cl₂可能与水蒸气反应形成HCl，再与ZnO反应生成ZnCl₂.

Volatilization mechanism of Zn on municipal solid waste incineration fly ash during thermal treatment

Under the condition of 650~1350℃, the effect of temperature and time on the volatilization rate of Zn in fly ash was investigated in this experiment. XAFs were used to analyze the morphological and structuralof Zn in fly ash and secondary fly ash. The chlorination reaction pathway of Zn was deduced by using Gibbs free energy theory and the verification test was carried out. The results showed that the temperature was the main factor affecting on the volatilization of Zn. The volatilization trend increased first with temperature and then decreased. The volatilization rate reached the highest at 1000℃, while the time had little effect on its volatilization. Zn was mainly volatilized in the form of chloride, according to the theoretical calculation and verification test of Gibbs free energy theory in each hypothetical reaction pathway, it was concluded that the chlorination reaction of Zn in the heat treatment was carried out in two steps. First, the chloride in the fly ash reacted with SiO₂ to form Cl₂, and then ZnO reacted with Cl₂ to form ZnCl₂, while a small part of Cl₂ may react with water vapor to form HCl, and then react with ZnO to form ZnCl₂.