Development of alumino-silicate refractories in Ghana

Abstract

Alumino-silicate (bauxite), andalusite, kaolin and clay were investigated for suitability in production of alumina, mullite and fireclay brick refractories. The raw materials were characterized by X-ray diffraction, differential thermal and silicate analyses. The X-ray diffraction analysis of alumina and mullite refractories fired at 1450 oC, and fireclay bricks fired at 1350 oC, indicated presence of corundum and alpha-alumina crystals. The values of thermal (fired) shrinkage, crushing strength, porosity, water absorption and bulk density determined were 31.1 %, 2.3 x 103 kg/m3, 4.86 x 106 N/m2 and 13.2 % for mullite; 30.2 %, 2.4 x 103 kg/m3, 3.20 x 106 N/m2 and W = 12.8 % for alumina; and 25.2 %, 2.1 x 103 kg/m3, 2.61 x 106 N/m2 and W = 11.8 % for fireclay, respective-ly. Bauxite, andalusite and special kaolin were identified as potential raw materials for developing alumina and mullite refractories for construction of high temperature kilns and furnaces operating at 1350 oC. The clay and kaolin minerals could be used to produce fireclay refractories for construction of incinerators operating at maxi-mum temperatures of about 1000 oC. The performance of the refractories was demonstrated by producing bric-ks to construct kilns and incinerators for the ceramic industries and hospitals. Journal of Applied Science and Technology Vol. 13 (1 & 2) 2008: pp. 72-75