Influence of Firing Temperature on Properties of High Alumina Bricks

To reduce production costs and make full and reasonable use of raw materials,high alumina bricks were prepared using tabular corundum and mullite as aggregates,sillimanite as intermediate particles,and white fused corundum powder,α-alumina micropowder,and Suzhou soil as the matrix,firing at different temperatures(1 420,1 440,1 460,1 480,1 500 and 1 520 ℃)for 4 h.The apparent porosity(AP),the bulk density(BD),the cold crushing strength(CCS),the thermal shock resistance(TSR),the refractoriness under load(RUL) and the creep rate of the samples were tested.The effects of the firing temperature on the creep rate(1 450 ℃ × 50 h,under a load of 0.2 MPa) of the samples were studied.The results show that with the sillimanite addition of 22.5 mass%,the sample fired at 1 460℃ for 4 h performs the best comprehensive properties:the AP of 17.5%,the BD of 2.75 g·cm-3,the CCS of 100.5 MPa,the TSR number of 35 cycles,the RUL of 1 682℃,and the creep rate of-0.428%,which can prolong the service life of furnaces.