Development of fireclay aluminosilicate refractory from lithomargic clay deposits

Lithomargic clay until now has not been utilised to produce refractory bodies due to its low plasticity. In this work, the development and evaluation of fireclay refractory material produced from lithomargic clay deposit has been studied by addition of clay binder. Three formulations were prepared by mixing, semi-dry moulding, drying and firing at temperatures ranging from 1200 to 1400 °C. The fired samples were investigated to determine their physical properties such as bulk density, apparent porosity, linear firing shrinkage, and cold crushing strength. The chemical and mineralogical compositions were also determined. The results show that the linear firing shrinkage values were within limits acceptable for refractory clays. The cold crushing strength increases as temperature increased to 1400 °C. Cold crushing strength increased with increasing binder content. The increase of the highly refractory phases (cristobalite and mullite) and the densification of the bricks due to the presence of fluxing agents were responsible for the high cold crushing strength values. The investigated properties indicate that lithomargic clay underlying bauxite deposits could be used to produce fire clay aluminosilicate refractories.