Hydrothermal conversion of Ti-containing minerals in system of Na2O–Al2O3–SiO2–CaO–TiO2–H2O
来源期刊：Rare Metals2016年第6期
论文作者：Yan-Xiu Wang Ting-An Zhang Guo-Zhi Lv Xiao-Feng Zhu Wei-Guang Zhang Li-Qun Xie
文章页码：495 - 501
摘 要：Titanium has a great effect on the digestion of bauxite in the Bayer process because it reacts readily at high temperatures in alkaline sodium aluminate solution.Under this consideration, the hydrothermal conversion of Ti-containing minerals in the system of Na2O–Al2O3–Si O2–Ca O–Ti O2–H2O with increased temperatures was studied based on the thermodynamic analysis and systematic experiments. The results show that anatase converts to Al4Ti2 SiO12 at low temperatures（60–120 °C）, which is similar to anatase in crystal structure. As the temperature continues to rise, Al4Ti2 Si O12decomposes gradually and converts to Ca3 Ti Si2(Al2Si0.5Ti0.5O14 at 200 °C. When the temperature reaches 260 °C, Ca Ti O3 forms as the most stable titanate species for its hexagonal closest packing with O2-and Ca2?. The findings enhance the understanding of titanate scaling in the Bayer process and clarify the mechanism of how additive lime improves the digestion of diaspore.
摘要：Titanium has a great effect on the digestion of bauxite in the Bayer process because it reacts readily at high temperatures in alkaline sodium aluminate solution.Under this consideration, the hydrothermal conversion of Ti-containing minerals in the system of Na2O–Al2O3–Si O2–Ca O–Ti O2–H2O with increased temperatures was studied based on the thermodynamic analysis and systematic experiments. The results show that anatase converts to Al4Ti2 SiO12 at low temperatures（60–120 °C）, which is similar to anatase in crystal structure. As the temperature continues to rise, Al4Ti2 Si O12decomposes gradually and converts to Ca3 Ti Si2(Al2Si0.5Ti0.5O14 at 200 °C. When the temperature reaches 260 °C, Ca Ti O3 forms as the most stable titanate species for its hexagonal closest packing with O2-and Ca2?. The findings enhance the understanding of titanate scaling in the Bayer process and clarify the mechanism of how additive lime improves the digestion of diaspore.
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