EFFECTIVE UTILIZATION OF HEAVY METAL ELEMENTS (ANTIMONY ETC.) IN THE REFUSE INCINERATED ASH

焚烧厂每年排放约5000万吨城市一般垃圾焚烧后的灰分。由于担心二恶英和砷等有害重金属对环境的影响，近年来主要采用熔融处理作为城市垃圾的处理工艺。然而，工厂的初始投资成本很大，维护所需的电力消耗也变得巨大。此外，连续运行也成为一个问题。一般城市垃圾焚烧产生的灰含有飞灰和底灰。虽然粉煤灰中主要含有重金属等有毒物质，但底灰中除微量铅外的有毒物质几乎不含。本研究以粉煤灰为研究对象，对有毒物质的环境污染控制和粉煤灰的有效利用进行了探讨。首先，对毒性较强的锑等有毒重金属的种类、浓度和分布进行了比较，并对焚烧灰中的砷等进行了检测，对焚烧灰的粒径分布进行了检测。在此基础上，对颗粒尺寸和重金属含量进行了比较。其次，尝试采用溶剂萃取等操作回收重金属。

Ash from incinerated general municipal wastes of annual about 50 million tons are discharged from incineration plant. Recent years, the melting processing is mainly advanced as a treating process of the municipal waste, because it is feared that the dioxins and harmful heavy metals such as the arsenic affect the environment. However, the cost of initial plant investment is big and the power consumption necessary for the maintenance becomes also enormous. Besides, it becomes also a problem to continuously run. Ash from incinerated general municipal wastes contains fly ash and bottom ash. Though toxic substances such as heavy metal are mainly included for the fly ash, the toxic substances except for the small lead are not almost included for the bottom ash.In this study, it focuses on fly ash, and then environmental pollution control of toxic substance and effective utilization of fly ash are examined. To begin with, type, concentration and distribution of noxious heavy metals such as the antimony that the toxicity is strong is said by comparing arsenic in incinerated ash, etc. are examined and the particle size distribution of incinerated ash is examined. On the basis of those results, the comparison between the particle size and the content rate of heavy metal is carried out. Next, the recovery of the heavy metal using solvent extraction operation, etc. is tried.