日本金属学会誌

J. Japan Inst. Metals, Vol. 41, No. 9 (1977),
pp. 883-889

Mechanism of CaO Dissolution into the Melts of CaO-SiO2-Fe2O3 and CaO-SiO2-MgO Systems

Fumio Noguchi1, Yasuaki Ueda1 and Tsutomu Yanagase2

1Department of Metallurgy, Kyushu Institute of Technology, Kitakyushu
2Department of Materials Science and Technology, Faculty of Engineering, Kyushu University, Fukuoka

Abstract:

The mechanism of CaO dissolution into molten slag was studied by applying the hot-filament method to melt about 5 mg of slag samples on the electrically heated Pt-Rh filament.
The results indicate that the molten slag migrates between the CaO crystal and a newly formed 2 CaO ⋅ SiO2 layer through the cracks as seen in CaO-SiO2 system. In the case of higher Fe2O3 content, the layers of the compounds 2 CaO ⋅ SiO2 and 3 CaO ⋅ SiO2 formed around the CaO crystal were not continuous but looked more like particles, which promoted the dissolution of CaO. In the case of higher MgO content (30% CaO-50% SiO2-20% MgO), no compound layer was observed on the CaO crystal, and Akermanite was formed around CaO in only the quenched sample.
The effect of additions of chlorides (MgCl2, CaCl2, LiCl, NaCl) upon the dissolution rate of CaO was studied in the CaO-SiO2 system. The results have revealed that among the chlorides, MgCl2 is most effective in breaking the compound layer formed arround CaO, but less in extent than CaF2 addition.


(Received 1977/01/6)

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