A POSSIBILITY OF SYNTHESIS OF HIGH-ALUMINA CEMENTS FROM DIFFERENT RAW MATERIALS

Abstract

Calcium aluminate cements with high Al₂O₃ content are synthesized from different raw materials. Raw materials used in the synthesis include: lime, tricalcium aluminate hexahydrate, aluminum hydroxide and sodium aluminate solution. The preparation of raw material mixture for sintering was performed in two ways: the first method of preparation of a raw material mixture was by mixing powdered components (Al(OH)₃ and CaO, Al(OH)₃ and 3CaO·Al₂O₃·6H₂O), another method included stirring into the liquid phase (NaAlO₂, CaO and Al (OH)₃) for a certain period of time at the temperature of 90°C, whereby the obtained solid phase was used as raw material for sintering. Chemical and mineralogical analysis (XRD) were performed on the cements obtained in synthesis. Based on chemical analysis it was concluded that the cements obtained were CAC 70 and CAC 80, as the Al₂O₃ content in these cements ranged from 70 to 75.37% for the first type, while the second type had a range of 77-79%. XRD analysis showed that the dominated minerals in cement CAC 70 were CaO• Al₂O₃ and CaO • 2Al₂O₃, and in cement CAC 80, mineral CaO • 2Al₂O₃, which is consistent with the findings published on these cements.