垃圾焚烧灰渣熔融处理重金属氯化-挥发反应分析

热力学分析表明,在800~1 000℃的较低温度区,以NaCl作为氯化剂,与垃圾焚烧灰渣熔融处理炉内气相中的SO3及H2O进行反应,生成硫酸盐Na2SO4,可以使重金属氯化-挥发所需氯源HCl的放出反应得以积极进行.此外,添加Al2O3于Na2O-SiO2熔渣相中,Na2O的活度得到很大程度的降低,从而促进熔融盐相中所生成的Na2SO4于炉内高温区的再分解反应,这不仅释放出炉内低温区重金属氯化-挥发反应所需的SO3,还可得到具有高化学稳定性的熔融残渣.

Thermodynamic Analysis of Chlorination-Evaporation of Heavy Metals During Melting of Ash from Municipal Waste Incineration

Thermodynamic analysis revealed that the presence of gaseous SO3 and H2O in the melting process of ash from municipal solid waste incineration leads to a reaction to form Na2SO4 and evolves HCl which is required for the chlorination-evaporation reaction with NaCl as a chloridizing agent at the comparatively low temperature from 800 to 1000°C. Moreover, the activity of Na2O is greatly lowered by adding Al2O3 to Na2O-SiO2 molten slag phase, thus boosting the redecomposition reaction of Na2SO4 to Na2O and SO3 through the reaction with slag phase at higher temperature zone. The residues of highly chemical stability can therefore be obtained.