Physico-Mechanical and Thermal Properties of Insulating Refractory Bricks Developed From Ikorodu and Osiele Fireclays and Agroforestry Wastes
This paper studies the physico-mechanical and thermal properties of insulating refractory bricks developed from selected Nigerian fireclays and agroforestry wastes. The as-received clays and agroforestry wastes were air dried, crushed and ground. Refractory bricks were produced with various weight percentage (60 - 95 %) of clay and (5 - 40 %) of agroforestry wastes and fired at temperature ranging from (950 – 1200oC). The bricks were characterized in accordance with ASTM standards to determine their chemical constituents, physical, mechanical and thermal properties. The microstructural examination of the bricks was carried out using Scanning Electron Microscope. The cost benefit analysis was also conducted. The results of the chemical analysis revealed that the major chemical constituent in the clays were silica (>45%) and alumina (>36%). The sawdust is more carbonaceous in nature with Loss on ignition (L.O.I 97.15) than both rice husk (43.30) and coconut shell (93.47). The porosity of the insulating brick increases from 26.51 - 84.6% as the volume of waste increases from 0 - 35%.The larger the pores (26.51 - 84.6%), the lower the strength (10,000 – 2,239.06kN/m2). The high degree of porosity enhanced the thermal insulating property (0.046 W/mK) of the refractory bricks. The cost benefit analysis carried out revealed that the price of the developed bricks (N261-265) are far lower than the cost of imported bricks. The economic savings is approximately 57 % per unit brick.