Kazumasa Matsushita*, Nobuki Shiragaki*, Ryuji Sato*, Takayuki Komatsu* and Kiyoshi Momonoi**

*Department of Chemistry, Nagaoka University of Technology
**Department of Civil Engineering, Nagaoka University of Technology

+ Correspondence should be addressed to Kazumasa Matusita:
Department of Chemistry, Nagaoka University of Technology
(1603-1, Kamitomicho, Nagaoka, Niigata-ken 940-21 Japan)

Abstract

Glasses were prepared bymelting the sewage sludge slag, and the relation between the properties and the chemical composition of the glasses, especially, the ratio of Fe2+/ (Fe2++Fe3+) was analyzed in detail. The glasses were dark brown and not transparent due to high concentration of iron oxide. It was found that the properties of the slag glass were similar to those of aluminosilicate glasses which are available commercially. It was possible to control the ratio of Fe2+/ (Fe2++Fe3+) in glass by adding graphite powder to the raw materials of glass. It was found that, as the fraction of Fe2+ ion increases,the thermal expansion coefficient increases, density decreases, glass transition temperature decreases and viscosity also decreases.

Key words: sewage sludge slag glass, iron ion, viscosity, thermal analysis, oxidation-reduction equilibrium