高温自蔓延法固化处置生活垃圾焚烧飞灰  

Immobilization of MSWI Fly Ash by High Temperature Selfpropagating Method

作　　者：肖博[1] 徐中慧[2] 

机构地区：[1]西南科技大学固体废物处理与资源化教育部重点实验室,四川绵阳621010 [2]西南科技大学非煤矿山安全技术四川省高等学校重点实验室,四川绵阳621010

出　　处：《环境科学与技术》2016年第5期56-59,128,共5页Environmental Science & Technology

基　　金：西南科技大学重点科研平台专职科研创新团队建设基金项目(14tdgk04)

摘　　要：将高温自蔓延反应用于生活垃圾焚烧飞灰(以下简称飞灰)的无害化处置,探索了Mg-Fe_2O_3-飞灰反应体系中最大飞灰含量(质量分数,下同),评估了不同飞灰含量下的无害化效果,研究了自蔓延反应过程中飞灰中重金属元素的挥发行为,并通过XRD和SEM分析探讨了自蔓延反应固化飞灰中重金属的机制。研究结果表明,系统维持自蔓延的飞灰含量最大为65%;经高温自蔓延处置后,飞灰中Pb、Cd、Cu和Cr的毒性浸出浓度分别由21.51、0.19、0.18和0.58 mg/L降低到0.53、0.12、0.06和0.07 mg/L以下;Pb、Cd和Zn等重金属在自蔓延反应过程中大量挥发,飞灰含量40%时其挥发率分别高达92.24%、88.66%和87.77%,Cr和Cu主要以铬矿物和氧化亚铜的形式固化于产物中。XRD/SEM结果表明飞灰高温自蔓延反应产物以玻璃相为主体,体系中残留重金属与低熔点物质形成固液共存相并随着反应的推进迅速冷却形成密实的固熔体,通过化学固化和物理固封作用固定于玻璃体中。High temperature self-propagating method was used for the disposal of MSWI fly ash（FA）. The maximum content of FA in the Mg-Fe2_O_3-FA system was investigated. Moreover, the effectiveness of non-hazardous process was evaluated and the transfer behavior of heavy metals in FA during the process was studied. The immobilization mechanisms of heavy metal elements were also explored based on XRD and SEM analysis. The results showed that the maximum content of FA is up to 65%, and the leaching concentrations of Pb, Cd, Cu and Cr drop from 21.51, 0.19, 0.18 and 0.58 mg/L to less than 0.53, 0.12, 0.06 and 0.07 mg/L respectively. Heavy metals such as Pb, Cd, and Zn volatilize heavily in the process of self-propagating reaction, and the amounts of evaporation is 92.24%, 88.66% and 40% respectively while the FA content is40%, while Cr in the form of cuprous oxide and Cu in the form of chromium minerals are immobilized in the products. XRD/SEM analyses showed that products exist as glass phase for the main body. Residual heavy metals in the system with low melting point materials form solid-liquid phase and cool rapidly to form close-grained solidified body subsequently. Heavy metals are immobilized by chemical bonding and physical encapsulation.

关 键 词：垃圾焚烧飞灰 高温自蔓延 重金属 固化 

分 类 号：X705[环境科学与工程—环境工程]