Study On The Performance About Working Lining On The Stirring Device Of KR Desulphurization

KR stirring desulfurization technology has a high desulfurization efficiency, less consumption desulfurizer, shorter operating time and lower metal depletion, over the past decade it has been rapidly expanded in China. the life of stirring device has an important impact on economic indicators of KR stirring desulfurization technology. The life of the stirring device is closely related to the performance of the thermal shock resistance, erosion and corrosion resistance of castable refractory lining,which is an important guarantee for high efficiency and economy of KR stirring desulfurization. In this paper, it can improve life of refractory lining for KR stirring and provide the basis for regulation and control by systematically studing the influencing factors of Al₂O₃-SiO₂ refractory castables such as the composition of the particle size, aggregate types and binder.Based on Andreassen particle density theory as foundation, the effect of critical grain size and particle size distribution of mullite castable on its density, strength and thermal shock stability has been studied in this paper; using pure calcium aluminate cement and SiO₂ powder as the main binders, the effect of binders on density, strength and thermal shock stability studied for ordinary fused mullites'castable has also been studied in this paper;we choice of fused corundum, bauxite and flint clay three aggregates and mullite aggregate conducting a comparative test for exploring the impact law of aggregates variety on the performance of Al₂O₃-SiO₂ refractory castables.Scanning electron microscopy (with spectroscopy), X-ray diffraction instrument etc. has been used in the tests on the analysis of phase composition and structure of samples. The result indicates that:1) Critical particle size and particle size composition do have a significant effect on dense and strength of castables after drying; under the experimental conditions, for mullite castable, the appropriate particle size composition is the critical size 8 mm or 5 mm, q for 0.27～0.29; and 3 mm, q for 0.29～0.31;2) It can improve cold density and intensity of castables by increasing critical particle sizes; but the effect of particle size distribution on the thermal shock is smaller, especially in the best performance at room temperature corresponding to the range of appropriate particle size composition, the critical size of three kinds of different castables a very small difference in thermal shock; three kinds of castables with different critical size are small difference in thermal shock;3) With the same critical particle size, mullite castable reaches the maximum packing density and the maximum intensity corresponding to the size composition is basically the same; 4) The sample bonding by CA-70 in four kinds of calcium aluminum cement(CA-65,CA-70,CA-75 and CA-80)reaches higher strength;apparent porosity of sample with 3% SiO₂ powder after drying reduced nearly 9% comparing to sample cement due to significant improvement in mobility, but the intensity is slightly lower; intensity of the sample bonding by CA-70 and SiO₂ powder after drying is highest (6MPa), apparent porosity increased only for 1.3% comparing to SiO₂ binder powder samples at the same time;5) The specimen combination by pure calcium aluminate cement begin sintering at 900℃; and the sample combination by SiO₂ powder has completely sintered of 900℃×3h, SiO₂ powder has a very clear role in promoting sintering of mullite castables;6) With the sintering temperature increased from 900℃to 1300℃, porosity of mullite castable sample deceased significantly nearly 1/3, cold strength increased significantly, which is mainly caused by amounts of liquid in 1300℃;7) Mullite castables are better than the castables with super bauxite,flint clay and corundum as its aggregate in cold performance,which is mainly caused by the properties of mullite itself and its appearance, which made it reach a higher accumulation dense in the choice of particle size distribution;8) The effact of 1⁰.088mm flint clay and bauxite equivalent alternative mullite aggregate for mullite castable's performance at room temperature will not significantly, but high temperature strength increased;9) The high-temperature strength of castable with bauxite fines instead of mullite powder increased, up to 7.6MPa, which is caused by the chemical composition and phase composition of raw materials.