Benefit of Matrix Alumina and Modern Dispersing Systems in Low Cement Castables

Abstract

The use of monolithic refractories has spread throughout various industries over the past few decades. Today it is common practice to install monolithics in heavy wear areas. In the past, only refractory bricks were used. Unlike bricks, unshaped products require sintering during operational use to obtain their final properties. Applications outside the iron and steel industry are often referred to as “industrial applications”. Industrial applications also demand improved castable properties such as better chemical stability, mechanical strength and abrasion resistance in intermediate temperature ranges. The service temperatures in industrial applications are often below 1200°C, so castables do not attain sufficient energy for strong sintering reactions. Matrix properties are important for refractory castables. They determine not only workability and strength, but also performance within an application. By optimising the overall particle size distribution of fine and superfine materials including the binder, better workability can be achieved. In addition, the physical properties of castables can be improved, especially in intermediate temperature ranges. Calcined and reactive aluminas and dispersing additives can also contribute significantly to the improvement of matrix performance with respect to water demand, setting control and strength development.