Enhancement of Insulating Refractory Properties of Selected Nigeria Fire-Clays Using Coconut Shell

Abstract

The use of coconut shell particulates to enhance the insulating refractory properties of Ukpor, Osiele and Kankara fireclays in Nigeria was studied in this paper. The chemical analysis of the raw materials was conducted using Atomic Absorption spectrometer. The samples used for different tests were prepared by mixing the clay, bentonite and coconut shell, of grain sizes of 212 - 600 μm. The prepared samples were air and oven dried for 24 hours at room temperature and at 110°C respectively. The samples were then fired at different temperatures in the range of 950°C to 1200°C at 50°C interval and at 2.5°C/min. The fired samples were investigated for their physical, insulating (thermal) and mechanical properties. Micro-structural examination was also carried out. The results indicate that clays with 25 wt% - 30 wt% coconut shell and grain sizes of 212 - 300 μm fired at 1150°C - 1200°C possess enhanced mechanical, physical and insulating (thermal) properties. The SEM micrograph revealed the formation of mullite phase in the bricks fired at 1150°C. Thus, high quality refractory bricks with enhanced insulating properties could be produced from Ukpor, Osiele and Kankara fire-clays blended with coconut shell particulates.