湿法预处理对垃圾焚烧飞灰中重金属的形态及风险影响研究

以某典型城市生活垃圾焚烧飞灰为研究对象,采用X射线荧光光谱仪(XRF)、X射线衍射仪(XRD)和电感耦合等离子体光谱仪(ICP)测定了焚烧飞灰的主要成分、矿物学组成和重金属含量,探讨了湿法预处理工艺对飞灰的化学组成、矿物学形态、化学形态及风险水平的影响。结果表明,飞灰的主要化学组成为O、Ca、Cl、Na、K等,占飞灰总质量的93.54%,其次含有0.04%~0.68%的Zn、Pb、Cu、Cr等微量重金属元素;经过湿法预处理,飞灰中可溶性氯盐具有较好的去除效果,且几乎所有重金属元素的不稳定形态(弱酸提取态和可还原态)比例都有一定程度的减少,有效降低了重金属的毒性、生物有效性及环境风险水平。本研究有助于降低焚烧飞灰的环境风险和探寻其资源化的有效途径。

Effects of Wet Pretreatment on Heavy Metal Speciation and Risk in Municipal Solid Waste Incineration (MSWI) Fly Ash

This paper studied the typical municipal solid waste incineration fly ash,tested the main content,mineralogical composition and heavy metal content by XRF,XRD and ICP,respectively,discussed the impact of wet pretreatment on chemical,mineralogical composition,chemical speciation and risk level.The results showed that the main chemical composition of fly ash was O,Ca,Cl,Na,K,etc,accounted for 93.54％ of the total mass of fly ash,and also 0.04％ ～0.68％ trace heavy metals,such as Zn,Pb,Cu,Cr,etc.After wet process pretreatment,most of the soluble chloride salts were removed.The unstable form of heavy metals such as weak acid soluble and reducible form were reduced,which decreased the toxicity,bioavailability and risk level of heavy metals.This study helps to reduce the environmental risk of incineration fly ash and explore the effective way for resource of fly ash.