The Synthesis and Mechanical Performances of Barium-Calcium Sulfoaluminate Mineral

摘要

Barium-calcium sulfoaluminate mineral, 2.75CaO·1.25BaO·3Al2O3·SO3 (C2.75B1.25A3 S ), has the excellent cementing properties. The present work was to investigate the formation process, mechanical performances of C2.75B1.25A3S and the effect of CaF2 on the synthesis and compressive strength of the mineral. Results derived by XRD, SEM-EDS and showed that small amounts of CaF2 could accelerate the decomposition of CaCO3, decrease the sintering temperature and promote the formation of C2.75B1.25A3S at a low temperature of 1300°C. Meanwhile, 11CaO·7Al2O3·CaF2 was found in the formation process of C2.75B1.25A3 S when CaF2 was added. In addition, the compounds, such as 12CaO·7Al2O3, BaO·Al2O3 and CaO·Al2O3 were formed in the sintering process of the mineral. Under the experimental conditions, a large quantity of barium-calcium sulfoaluminate mineral was found at about 1300-1350°C. When temperature was higher than 1400°C, it began to decompose slowly. The synthesized barium-calcium sulfoaluminate mineral has the properties of high early strength and the compressive strength at 1350°C that is the highest than the samples sintered at other temperatures. The small amount of CaF2 can increase the early mechanical performance of the mineral and the optimal content of CaF2 is 1.5wt%.^