Utilisation of South Libyan clay for preparation of mullite-alumina based refractory ceramics

Abstract

This work aims to benefit from the wide spreaded clay in south Libya with some alumina (Al₂O₃) additions to prepare and characterise mullite-alumina containing refractory ceramics. The starting materials used in this investigation are local raw clay and chemical aluminium oxide (Al₂O₃). Based on a previous geological survey carried out by the industrial research centre (Tripoli), four different clay samples were selected from different locations of the south of Libya. Representative samples of the four selected clays were investigated using X-ray diffraction (XRD) and differential thermal analysis. The four clay samples were used separately together with aluminium oxide to prepare six different batches containing different proportions of alumina from 0 up to 60% with an increament of 10%. The mullite containing bodies were investigated through their mineralogical compositions using XRD and scanning electron microscopy (SEM) attached with energy dispersive X-ray unit (EDX). The sintering, mechanical and refractory properties of the prepared mullite containing bodies were tested according to the international standard specifications. It is concluded that the densification, mechanical and refractory properties are improved as the alumina content increases on the expense of clay. Mixes containing 60% clay : 40% alumina and 50% clay : 50% alumina respectively, especially those prepared from Agar clay are characterised with good sintering, high mechanical and high refractory properties.