垃圾焚烧飞灰中重金属的形成机理

Mechanism of Heavy Metals Formation in MSW Incinerated Fly Ash

以常州市环境卫生综合厂垃圾焚烧车间的飞灰为例,比较深入地分析了飞灰中重金属的来源与形成机理。研究结果表明,由于不同种类重金属及其混合物的蒸发点差异较大,在生活垃圾中的含量也各不相同,所以它们在飞灰中的含量以及在底灰和飞灰的分配比例上都有很大的差异、锌、铅、镉等挥发性重金属在飞灰中的含量明显高于底灰。

In this work, the incinerator fly ash generated from Changzhou MSW Incineration Plant has been sampled and characterized in detail. The relationship between heavy metals contents in fly ash and in solid wastes incinerated was calculated. The heavy metal contents of fly ash, especially lead and cadmium, are very high. According to the existing regulations in China, the fly ash is viewed as a hazardous waste. The contents of heavy metals in fly ashes are found to be a function of those in the municipal solid waste incinerated. Hence, it is important to prevent the heavy metals waste from being incinerated in order to reduce the contents of toxic metals in the fly ash. Moreover, the elemental contents of the fly ash are also closely related to the melting and boiling points of the elements (metals or compounds) con-cerned. In general, the lower the melting and boiling points for either elements or compounds (oxides, sul-fates, and chlorides), the higher contents for the cor responding elements in the fly ash will be Hence, it is important to control the running conditions of a incinerator.