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Formation kinetics and transition mechanism of CaO·SiO 2 in low-calcium system during high-temperature sintering
Journal of Central South University ( IF 4.4 ) Pub Date : 2020-12-23 , DOI: 10.1007/s11771-020-4545-1
Xiao-lin Pan , Wei-xue Cui , Can Zhang , Hai-yan Yu

The crystal structure, formation kinetics and micro-morphology of CaO·SiO2 during high-temperature sintering process were studied in low-calcium system by XRD, FT-IR, Raman and SEM-EDS methods. When the molar ratio of CaCO3 to SiO2 is 1.0, β-2CaO·SiO2 forms firstly during the heating process, and then CaO·SiO2 is generated by the transformation reaction of pre-formed 2CaO·SiO2 with SiO2. 3CaO·SiO2 and 3CaO·2SiO2 do not form either in the heating or sintering process. Rising the sintering temperature and prolonging the holding time promote the phase transition of 2CaO·SiO2 to CaO·SiO2, resulting in the sintered products a small blue shift and broadening in Raman spectra. The content of CS can reach 97.4% when sintered at 1400 °C for 1 h. The formation kinetics of CaO·SiO2 follows the second-order chemical reaction model, and the corresponding apparent activation energy and pre-exponential factor are 505.82 kJ/mol and 2.16×1014 s−1 respectively.



中文翻译:

CaO·SiO 2在低钙体系中高温烧结过程中的形成动力学和转变机理

通过XRD,FT-IR,Raman和SEM-EDS方法研究了低钙体系中CaO·SiO 2高温烧结过程中的晶体结构,形成动力学和微观形貌。当碳酸钙的摩尔比3与SiO 2为1.0,β-2CaO·的SiO 2点在加热过程中的形式首先,然后的CaO·的SiO 2是由预先形成的2CaO·二氧化硅的转化反应产生的2用的SiO 2。在加热或烧结过程中均未形成3CaO·SiO 2和3CaO·2SiO 2。升高烧结温度并延长保温时间可促进2CaO·SiO 2的相变到CaO·SiO 2,导致烧结产物的蓝移小,拉曼光谱变宽。在1400°C烧结1 h,CS含量可达到97.4%。CaO·SiO 2的形成动力学遵循二级化学反应模型,相应的表观活化能和前指数因子分别为505.82 kJ / mol和2.16×10 14 s -1

更新日期:2020-12-23
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