Influence of Grog Size on the Performance of NSU Clay-Based Dense Refractory Bricks

Abstract

The suitability of using local kaolin (Nsu clay) and Nsu clay grog to enhance efficiency (reduce shrinkage, improve abrasion and reduce porosity) in the production of dense refractory bricks was studied. The chemical analysis, crystal structure examination and microstructural analysis were determined using the atomic absorption spectrophotometer (AAS), x-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The physical properties in terms of refractoriness, linear shrinkage, bulk density and apparent porosity as well as mechanical properties in terms of cold crushing strength (CCS) were carried out using American Society for Testing and Material (ASTM) stipulated standard methods. Test specimens (sample A = 20, sample B = 30 and sample C = 40 % grog sizes) were prepared and tested using the standard methods. The overall chemical and structural analysis of the raw Nsu clay showed that it is rich in SiO2 (59.20 wt. %) and Al2O3 (26.30 wt. %) with trace amounts of MgO, Fe2O3 and K2O, hence an alumino-silicate clay. The refractory properties measured showed acceptable and efficient results. Maximum apparent porosity (20.22 %) and CCS (61.77 MPa) were obtained at sample B = 30 % grog size.