Leaching Properties of Slag Produced by Melting Incineration Residue and Fly Ash from Municipal Solid Waste

Ken-ichi Tahara*, Junya Nishino* and Kiyosi Momonoi**
* Environmental & Chemical Processes Department, Technical Development & Engineering Center, Ishikawajima-Harima Heavy Industries Co., Ltd.
** Environmental System Engineering, Nagaoka University of Technology
+Correspondence should be addressed to Ken-ichi Tahara:
(1 Shin-nakahara-cho, Isogo-ku, Yokohama, 235-8501 Japan)

Abstract
The leaching properties of slag produced from melting processes were studied to evaluate the effects of melting and its impact on the environment. 24 kinds of synthetic slag and 7 types of slag from different municipal solid wastes (MSW) and furnaces were examined.
Leaching properties of slag were examined for the amount of acid neccessary to keep the leachate at pH4. The chemical stability of slag given by the amount of acid corresponded well with the chemical components and texture of the slag. This leaching method was useful to evaluate the effect of melting and its impact on the environment.
Slag which had homogeneous amorphous texture and low basicity(CaO/SiO2 < 0.7)was chemically stable and was only slightly affected by the melting process and the characteristics of the MSW.

Key words: slag, leaching property, melting process, municipal solid waste, basicity, heavy metal