Abstract
The Metal Mining Agency of Japan has carried out a four-year Technical Development project on Disposal Free Treatment of Secondary Fly Ashes from Municipal Waste Incineration. We have attempted to apply the MF (Mitsui-type blast Furnace) process, which is employed to treat electric arc furnace dust, to recover heavy metals contained in the fly ashes along with decomposing dioxins to produce a slag which could be used for cement production.
The main results of our experiments are as follows;
1) Approximately 90% of heavy metals (mainly zinc and lead) contained in the secondary fly ashes can be recovered as raw materials, thereby contributing to non-ferrous metals production,
2) The slag generated from the secondary fly ash treatment using the MF process can be used as a raw material for cement production, thereby utilizing decontamination technology without landfill,
3) Two stages of alkaline washing will be needed to avoid equipment erosion caused by chlorine contained in the fly ashes, and
4) The ratio of decomposition of dioxins is above 99%.
Since 2003, based on the results of this project, Miike Smelter Co., Ltd., subsidiary of Mitsui Mining & Smelting Co., Ltd. has been treating fly ashes from municipal waste incineration at the MF plant in Omuta city, Fukuoka prefecture, Japan.
