重庆市垃圾焚烧飞灰中重金属含量及浸出毒性分析

On Particle Size Distribution,Gross Contents of Heavy Metals and Its Leaching Behavior of Fly Ash from Municipal Solid Wastes Incineration of Chongqing

采用筛分法研究了重庆市春、秋季生活垃圾焚烧飞灰的粒径分布,分析了各粒径颗粒中Cu,Zn,Mn,Pb,Cd,Ni,Cr和Hg的总量.并研究了在GB5085.3-2007和USEPA-TCLP浸出条件下不同粒径范围内的重金属浸出量的差异.结果表明,秋季飞灰粒径相对春季较小,春秋两季90%以上的飞灰粒径小于250μm,其中春季飞灰粒径为83～105μm的最多,约占总量的40%,而秋季飞灰粒径为105～149μm的最多,约占总量的45%.飞灰中除Ni以外,其他重金属总量随粒径减小呈先减小后增大的趋势,其中秋季飞灰重金属总量除Fe和Zn外均比春季含量高.国标GB5085.3-2007体系下飞灰的浸出毒性鉴别显示重庆市春秋两季垃圾焚烧飞灰中Cu,Zn和Ni以及春季Cr未超出浸出毒性限值,Pb,Cd和秋季Cr分别超出国家标准.TCLP浸出体系下春秋浸出毒性鉴别结果Pb,Cr和Cd均超出标准限值,表明不同浸出方法对重金属的浸出量影响很大.

The distributions in different particle sizes of municipal solid waste incinerator （MSWI） fly ash in spring and autumn have been studied in sieve method, and the heavy metal contents of Cu, Zn, Mn, Pb, Cd, Ni, Cr and Hg in different particles have been measured, and the heavy metal leaching amount in the different particle size have also been studied under the GB5085.3-2007 and USEPA-TCLP leaching procedure, respectively. The results show that the particle size of fly ash in autumn is relatively small than that of in spring, more than 90% of particle size of fly ash in spring and autumn are less than 250 μm, and the particle size in 83-105μ m of fly ash in spring distributes most, accounting for about 40% of the total, but 105--149 μm in autumn distributes most, accounts for about 45% of the total. The content of heavy metals decreases first and then increased with the decreasing particle sizes except for Ni, and the content of heavy metals in the spring is higher than that of in autumn except for Fe and Zn. Under the GB5085.3- 2007 leaching procedure, the leaching content of Cu, Zn and Ni in MSWI fly ash in both spring and autumn and Cr in spring are not beyond limited standard, but Pb and Cd in both spring and autumn and Cr in autumn are beyond limited standard. However, under TCLP leaching procedure, the leaching content of Pb, Cr and Cd in both spring and autumn are beyond the standard limits, so it shows that there is an important influence on the concentration of the heavy metals under different leaching procedure.