Takeo Urabe* and Shigeo Kobayashi*

* Chief researcher, The Tokyo Metropolitan Research Institute for Waste Management

+ Correspondence should be addressed to Takeo Urabe:
(2-chome-tisaki, aomi, koto-ku, Tokyo 135-0064 Japan)

Abstract

An investigation of properties and resource recovery of metal generated in ash melting arc-type furnaces was undertaken. The percentage of metal generated by water quenching was 10-15 % of slag and metal produced. Granular metal has several holes inside, the average diameter of granular metal was 1.8mm and the apparent specific gravity was 3.28 t/m3. The granular metal has a Vickers hardness of about 950 and high corrosion-resistance. The granular metal is an alloy composed of Fe (68.17%), Si (15.03%), Cu (9.33%), and various metal components such as Ni, Cr, Sn, Ag, Au, etc. and was characterized by P and Cu conditions which are ordinarily avoided in iron manufacturing. Thermo-dynamic considerations indicated that Si and P in granular metal might be reduced by Al/C and by CO, respectively and moved to the metal. Interior shrinkage cavities generated by melting in air was decreased by vacuum melting. However, the reduction was not enough for further utilization and further improvements in smelting, casting, etc. are necessary. It was found that copper alloy separated with iron alloy through the gradual cooling of fused metal with a copper concentration of more than about 25%. The use of such metal is expected for materials of low grade casting and iron manufacturing, etc., including weight balance applications.

Key words: ash melting furnace, metal, resource recovery, vacuum melting