Ceramics-Silikáty 55 (2) 169-175 (2011)

The effect of dolomite type and Al₂O₃ content on the phase composition in aluminous cements containing spinel

M. R. Pouyamehr, Z. A. Nemati, M. A. Faghihi Sani, R. Naghizadeh

In this paper, the effect of dolomite type and Al₂O₃ content on the phase composition in aluminous cements containing MA spinel is investigated. For this reason, the raw and calcined dolomites are used as raw materials along with calcined alumina in the preparation of the cement. Then, different compositions are prepared at 1350°C using the sintering method and their mineralogical compositions are investigated using the diffractometric technique. Also, their microstructures arre evaluated. The results indicate that raw materials used have great effect on the type and amount of formed phases in cement composition. Independently of the dolomite type used, a mixed phase product consisting of spinel accompanied by CA and CA₂ is obtained. The content of CA phase in the cement composition is decreased with increasing of Al₂O₃ in the raw materials composition. On the other hand, the content of CA₂ phase is increased with the addition of Al₂O₃. In addition, the results show that the formation of C₁₂A₇ is favored by use of calcined dolomite.

Keywords: Aluminous cement; Spinel; Dolomite; CA; C₁₂A₇