Characterization of alumina crucible made from aluminum industrial waste

摘要

The use of aluminum waste sludge as a raw material in the ceramic industry was studied due to its economical, energy, and environmental advantages. This study focused on preparation and characterization of alumina crucibles made from aluminum industrial waste for the purpose of glass melting. The main objective of this project was to reduce or replace both alumina powder and alumina crucibles imported from abroad. The trial formulas were composed mainly of calcined aluminum waste (CAW) from aluminum factory. Additionally, sodium silicate and sodium salts of polycarboxylic acid were used as deflocculants while polysaccharide was used as a binder. The crucibles were shaped by the slip casting method and then sintered at 1600 and 1700 degrees C. The water absorption, bulk density, apparent porosity, and 3-point bending strength were investigated. After sintering at 1600 and 1700 degrees C, the crucible with 75 wt% of aluminum waste (75AC formula) showed 0.18 and 0.06% water absorption, 3.41 and 3.36 g/cm(3) bulk density, 0.61 and 0.20% apparent porosity, and 139.11 and 159.84 MPa bending strength, respectively. The coefficient of thermal expansion between 25 and 1000 degrees C of 75AC composition was 6.9807 x 10(-6)/degrees C and the crucibles passed three cycles of 20-200 degrees C thermal shock resistance testing. The resulting crucibles were successful in the trial for glass melting between 1450 and 1500 degrees C without either breaking or affecting the glass component. Calculation of the production costs for these lab-scale trials revealed that the crucible made from aluminum waste was about 70% cheaper than that made from commercial alumina. As a result, this study indicated that the alumina crucible made from aluminum industrial waste performed comparably with the commercial crucible being used for glass melting purposes.