LAUSR

Sr-bearing ye’elimite is synthetized through substitutions of Sr2+ ions for Ca2+ ions in ye’elimite (C4A3$). Here, we report formation process and the kinetic analysis of 3CaO·SrO·3A2lO3·SO3 (C3ŠA3$) which is a type of Sr-bearing ye’elimite. Clinkers of C4A3$ and C3ŠA3$ were respectively sintered at different temperatures and prolong time, Rietveld quantitative phases analysis was conducted to quantify the clinkers. Specific to the isothermal process, different kinetic models were used for statistical fitting. Additionally, through fitting with Arrhenius equation, values of activation energy for both C4A3$ and C3ŠA3$ were obtained and compared. The results show that formation of C3ŠA3$ mainly derives from reaction between intermediate phases and sulfates. Overlapping temperature range for formation of both C4A3$ and C3ŠA3$ is between 1150 and 1300 °C, C3ŠA3$ tends to be stable at 1350 °C until 180 min. Formation mechanism of C3ŠA3$ accords with three-dimensional diffusion, Jander model yields the highest correlation coefficients for both C4A3$ and C3ŠA3$. Activation energy for formation of C3ŠA3$ equals to 367.9 kJ/mol, which is higher than that of C4A3$ (300.8 kJ/mol). Sintering temperature mainly affects micro-morphology of C3ŠA3$ particles, but has no influence on elemental distribution and compositions.