Hydrothermal treatment of MSWI fly ash for simultaneous dioxins decomposition and heavy metal stabilization  

作　　者：Jinlong XIE Yuyan HU Dezhen CHEN Bin ZHOU 

机构地区：[1]Thermal&Environmental Engineering Institute,Tongji University,Shanghai 200092,China

出　　处：《Frontiers of Environmental Science & Engineering》2010年第1期108-115,共8页环境科学与工程前沿（英文）

基　　金：the National High-Tech Research and Development(863)Program of China(Grant No.2008AA06Z340);the National Natural Science Foundation of China(Grant No.50708068).

摘　　要：Researches on the hydrothermal treatment of municipal solid waste incineration(MSWI)fly ash were conducted to eliminate dioxins and stabilize heavy metals.In order to enhance decomposing polychlorinated dibenzodioxins(PCDDs)and polychlorinated dibenzo-furans(PCDFs)during hydrothermal process,a strong reductant carbohydrazide(CHZ)is introduced.A hydrothermal reactor was set up by mixing raw MSWI fly ash or the pre-treated fly ash with water and then heated to a pre-set temperature;CHZ was spiked into solution according to specially defined dosage.Experimental results showed that under the temperatures of 518 K and 533 K,the decomposition rates of PCDDs/PCDFs were over 80%and 90%,respectively,by total concentration.However,their toxic equivalent(TEQ)decreased only slightly or even increased due to the rising in concentration of congeners 2,3,7,8-TCDD/TCDF,which might be resulted from the highly chlorinated congeners losing their chlorine atoms and being degraded during the hydrothermal process.Better results of TEQ reduction were also obtained under the higher tested temperature of 533 K and reactor with addition of 0.1%wt CHZ was corresponded to the best results.Good stabilization of heavy metals was also obtained in the same hydrothermal process especially when ferrous sulphate was added as auxiliary agent.

关 键 词：municipal solid wastes incineration(MSWI) fly ashes polychlorinated dibenzo-dioxins(PCDDs) polychlorinated dibenzo-furans(PCDFs) hydrothermal heavy metal stabilization 

分 类 号：O61[理学—无机化学]