Improving in situ spinel refractory castables using a novel binder

The objective of this paper is to find an efficient binder by investigating binders such as fireclay, white Portland cement and gypsum with different compositions, and ultimately to introduce a suitable binder composition. Evaluation of physical properties and microstructure of castables were performed by mechanical (splitting tensile strength) test, porosity measurements, bulk density measurements, X-ray diffraction spectroscopy and scanning electron microscopy. The results revealed that the performance of the new binder is much better than that of conventional binders such as calcium aluminate cement, because it creates strong bonds between the particles and improves the in situ spinel formation and sintering/diffusion of particles with each other at high temperatures. Analyzing the prepared samples with new binder also demonstrated that the increase of refractory material in binder composition, leads to creation of the strong and cohesive phases and bonds between the particles (such as mullite), and therefore, increases the driving force of in situ spinel phase formation and ultimately improves the performance of refractory masses at high temperatures.