Influence of existence state of Fe3+/Ti4+ on structure of Al2TiO5ss/3Al2O3 · 2SiO2ss composite
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摘要: 借助XRD、SEM和能谱分析仪等手段,研究了1 600℃煅烧中低品位矾土制备的钛酸铝/莫来石(Al2TiO5ss/3Al2O3 · 2SiO2ss)复合材料经1 200℃保温12 h后结构的稳定性。结果表明:高温煅烧中低品位矾土后,其合成材料的结晶物相组成为3Al2O3 · 2SiO2ss、Al2TiO5ss和少量残存的方石英;Fe3+或Ti4+离子以不同形态赋存于结晶相(3Al2O3 · 2SiO2ss和Al2TiO5ss)和非晶相。含Fe3+/Ti4+离子的3Al2O3 · 2SiO2ss将Al2TiO5ss结晶相分割,使其蜷缩其间,并抑制Al2TiO5ss的分解;高温下,二者因组成元素相近而致使晶界融合,进而共同构建了体系牢固的致密骨架结构。由3Al2O3 · 2SiO2ss和Al2TiO5ss等高温物相构成的致密结构将非晶相挤压于空隙结构的3Al2O3 · 2SiO2ss晶间,避免了低熔点相富集带来的不利影响,进而赋予该Al2TiO5ss/3Al2O3 · 2SiO2ss复合材料良好的结构稳定性。
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关键词:
- Fe3+/Ti4+离子 /
- 3Al2O3 · 2SiO2ss /
- Al2TiO5ss /
- 结构稳定性
Abstract: The structural stability of Al2TiO5ss/3Al2O3·2SiO2ss composite based on middle-low grade bauxite calcined at 1 600℃ and held subsequently at 1 200℃ for 12 h was studied by XRD, SEM and energy dispersive spectroscope (EDS). The results show that after middle-low grade bauxite being calcined at 1 600℃, its crystal phase composition consists of 3Al2O3·2SiO2ss, Al2TiO5ss and a little cristobalite, in which Fe3+/Ti4+ cations exsit in crystalline phases (3Al2O3·2SiO2ss and Al2TiO5ss) and amorphous phase (silicate) in different forms. Al2TiO5ss is separated and huddled by 3Al2O3·2SiO2ss containing Fe3+/Ti4+ cations, restraining its decomposition; in addition, both 3Al2O3·2SiO2ss and Al2TiO5ss build compact skeleton structure of Al2TiO5ss/3Al2O3·2SiO2ss synthesis system based on middle-low grade bauxite due to their near element composition, which avoids appearance of silicate phases with low melting point and further endows good structural stability.-
Key words:
- Fe3+/Ti4+ cations /
- 3Al2O3 · 2SiO2ss /
- Al2TiO5ss /
- structural stability
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