城市垃圾焚烧飞灰中重金属的化学形态分析

Research on Chemical States of Heavy Metals in Municipal Solid Waste Incineration Ashes

化学形态分析是一种认识重金属环境行为的有效方法。采用这种方法,可使焚烧飞灰中重金属的毒性将不再仅仅是简单地依赖于其总含量,而是与不同形态重金属在环境中的迁移转化行为相联系。依据化学形态分析的结果,可以了解焚烧飞灰中不同重金属的存在形式,从而为焚烧飞灰的处置利用研究提供科学依据。采用连续化学萃取法对焚烧飞灰中重金属的化学形态进行了研究。结果表明,焚烧飞灰中主要重金属的形态,有些属于不稳定结合态,有些则属于稳定结合态,在处置利用焚烧飞灰时应尽可能地将飞灰中的重金属由不稳定态转变为稳定态。

The sequential chemical extraction(SCE) method is one effective method for cognition of environment behavior of metals. Using this method, the metal toxicity of municipal solid waste incineration(MSWI) fly ash will not only depend on their total content, but also relate to transferring and transforming behavior of different forms of metals in the environment. Based on results of SCE, different existing forms of metals in MSWI fly ash can be understood to provide scientific basis for the treatment and utilization of MSWI ashes. The authors used the SCE method to study the chemical states of heavy metals in MSWI ashes. The results showed that in main heavy metals some states exist in stable forms and other states exist in unstable forms. It is suggested that chemical states of heavy metals should be converted from unstable to stable forms as far as possible when MSWI ashes are treated and utilized.