Authors:
Marcel Bastian | Forschungsgemeinschaft Feuerfest e. V. | Germany
Maren Sollbach | Forschungsgemeinschaft Feuerfest e. V. | Germany
Dr. Johannes Kasper | Forschungsgemeinschaft Feuerfest e. V. | Germany
Dr. Christian Dannert | Forschungsgemeinschaft Feuerfest e. V. | Germany
Dr.- Ing. Ashish Pokhrel | Hochschule Koblenz | Germany
Prof. Dr. rer. nat. Olaf Krause | Hochschule Koblenz | Germany
Many, sometimes contradicting factors which influence the rheological properties of refractory castables are given in the state of the art. Some authors report a predominant influence of the rheology of the matrix suspension, while others mention an exclusive correlation between the aggregates and the rheology of refractory castables. Yet others describe that all raw materials of a refractory castable together determine the rheology of it. As a result, improving the rheological properties of refractory castables is not as straightforward as it could be.
Therefore, the results of modifications in the matrix suspension, in the aggregates and in the overall composition of refractory castables on their rheological properties were determined. This was done by measuring the shear rate dependent viscosity of these castables with a new lifting sphere viscometer.
It is shown that the matrix composition as well as the aggregates are responsible for the rheology of refractory castables. The rheology of refractory castables is much more complex than presented in the state of the art and depends on all the raw materials used and their properties. It is demonstrated that negative effects like strong dilatancy or high viscosity can be supressed by changing the matrix composition, the aggregates, or both. As such, there is a large toolbox to improve the rheological properties of refractory castables.