Preparation of Calcium Aluminate Cement by Self-propagating High-temperature Synthesis (SHS)

摘要

Calcium aluminate cements are conventionally prepared by solid state sintering method, and have been mainly used as binders of the refractory castable.In the paper, effort has made to synthesize calcium aluminate cement by self-propagating high-temperature synthesis (SHS) using calcium peroxide powders (CaO2), aluminum powders (Al) and alumina powders (Al2O3).The phase compositions and crystal morphology of the synthesized calcium aluminate powders were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) with Energy Dispersive Spectrometer (EDS).It was found that the phase compositions of synthesized products were CA, CA2 and C12As with well crystallized morphology;CA2 was dispersing in CA as bulk grains with clear boundary.When the molar ratios of CaO/Al2O3 decreased, the content of CA2 increased, whereas the contents of CA and C12A7 decreased.When the CaO/Al2O3 molar ratio was 0.8, the phase composition of synthesized calcium aluminate powders was equal to that of commercial calcium aluminate cement Secar71.