Spinel (MgAl2O4) containing high alumina refractory cements are in high demand by the glass, cement and metallurgy industries. Spinel-based cements improve thermomechanical strength and minimise slag attack. In addition they can give outstanding improvements to lining life when compared with other refractory materials.
Spinel cements are normally produced by a sintering process starting with synthetic spinel and high alumina content cements. The problem with this is the high cost of sintered and electrofused spinel raw materials. A solution to this is to generate the spinel phase in-situ when making the refractory materials from active alumina and high purity dolomites.
Recent work from Araceli Elisabet Lavat and María Cristina Grasselli from Universidad Nacional del Centro de la Provincia de Buenos Aires seeks to better understand this potential new processing route.
The research work, published under AZojomo (OARS), seeks to establish the feasibility of application of Agentinian dolomite raw materials in preparing refractory cements. The starting materials were fully characterized for particle size and chemical and mineral composition by laser granulometry, fluorescence, X-ray diffraction (XRD) and FTIR techniques.
The phase changes during cement synthesis up to 1450ºC were studied by the combination of XRD and infrared spectroscopy. The research found the optimal temperature for an in-situ spinel formation was 1450ºC.