Co₂O₃-doping effect on the formation of 3CaO·3Al₂O₃·CaSO₄

Abstract

The Co₂O₃-doping effect on the formation of 3CaO·3Al₂O₃·CaSO₄ from CaCO₃-Al₂O₃-CaSO₄·2H₂O mixtures was investigated by means of SO₂ emission behavior, chemical analysis, X-ray diffraction, differential thermal analysis and scanning electron microscopy. The experimental results show that Co₂O₃ addition increases the reactivity of the CaCO₃-Al₂O₃-CaSO₄·2H₂O system significantly, by reducing SO₂ emissions in combustion and f-CaO contents in the clinkers, promoting the nucleation and growth of 3CaO· 3Al₂O₃·CaSO₄, and intensifying the formation of 3CaO·3Al₂O₃·CaSO₄. Moreover, Co₂O₃ addition lowers the formation temperature of 3CaO·3Al₂O3·CaSO₄ by 18 °C, and similarly increases the thermal stability of it at a wider temperature range.

Keywords

3CaO·3Al₂O₃·CaSO₄ / Co₂O₃ / SO₂ emission / thermal analysis

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