Journal of the Chinese Ceramic Society, Volume. 51, Issue 3, 594(2023)
Reaction Mechanism of Mineralizers Ferrosilicon Nitride and Calcium Carbonate in Silica Bricks
Silica bricks only used the combined mineralizer of calcium hydroxide and iron scale in the early domestic production. It is feasible and necessary to explore novel mineralizers to improve the performance of silica bricks. In this paper, novel silica bricks were prepared with ferrosilicon nitride and calcium carbonate as mineralizers instead of calcium hydroxide and iron scale. The prepared silica bricks have good properties, and the content of tridymite with 2% ferrosilicon nitride and calcium carbonate added reaches 62% and 65%, respectively. The effects of ferrosilicon nitride and calcium carbonate on the formation of tridymite in silica bricks were investigated by X-ray diffraction and scanning electron microscopy. The results show that in the silica brick with ferrosilicon nitride as mineralizer, Si3N4 network formed by the intertwined columnar Si3N4 in the sea urchin-like structure ferrosilicon nitride protects Fe and Fe3Si through its oxidation reaction, thereby achieving a higher FeO/Fe2O3 ratio and a lower liquid formation temperature in the FeO-Fe2O3-SiO2 ternary phase. The FeO/Fe2O3 ratio in the liquid phase fluctuates at a high temperature, and then the constant change of the solubility of tridymite in the saturated liquid phase promotes the crystallization of tridymite due to the reducibility of Fe, Fe3Si and Si3N4. When calcium carbonate is used as a mineralizer of silicon brick, the formation temperature of the liquid phase in the brick is increased to 1 436 ℃. Before that, the reactions in the bricks are mainly the decomposition of calcium carbonate and the transformation from β-quartz to α-quartz and to metastable α-cristobalite. The increase of the formation temperature of the liquid phase does not reduce the content of tridymite in the brick, and the content of glass phase in the brick is less than that in the brick with iron mineralizer.
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ZHANG Xiuhua, MA Chenhong, QIAN Yu, YANG Jing, SUN Yang, LI Yong. Reaction Mechanism of Mineralizers Ferrosilicon Nitride and Calcium Carbonate in Silica Bricks[J]. Journal of the Chinese Ceramic Society, 2023, 51(3): 594
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Received: Oct. 11, 2022
Accepted: --
Published Online: Apr. 10, 2023
The Author Email: Xiuhua ZHANG (zhangxiuhuajj@163.com)
CSTR:32186.14.