To stably produce slag for a cement raw material having low chromium concentration and favorably having high hydration reactivity from steelmaking slag.
A reducing material is added to the steelmaking slag containing a chromium oxide, having a basicity of 1.5 or more and having an Fe content of 10 mass% or more, stirred and mixed at 1,000°C or higher and then cooled. In reduction treatment to perform stirring and mixing at a high temperature, an iron oxide is reduced together with the chromium oxide, metal iron and metal chromium in the slag are coagulated physically by stirring action and then a metal component containing chromium comes to have a form being easily separated and removed from the slag. Hydration reactivity as the cement raw material is enhanced by that chromium and iron are reduced so as to be a non-solid solution state by reduction treatment and that a cooling condition after the treatment is optimized so that a ratio of γ phase in 2CaO-SiO
COPYRIGHT: (C)2010,JPO&INPIT
Hiroyuki Tobo
Kazuya Yabuta
Akio Hayashi
Chiaki Yoshizawa
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