Preparation And Research Of Bauxite-based Sintered Corundum By Vacuum De-airing Extruder

Fused corundum is important raw material of refractory, but their production process consume electric energy largely and pollute severely,which isn't tally with the country's development patterns to build a resource-saving and environmental frien- dly society. On the basis of our country's rich bauxite resources,this paper expect to develop an alternative to the fused corundum by means of vacuum de-airing extruder.Using existing bauxite ore,by the way of breaking,adding materials such asα-alumina, commercial alumina and aluminum hydroxide ,vacuum-pumping,calcining can produce bauxite chamotte. The effect of different molding process, calcination temperature,holding time and particle size of materials and other factors to the performance of specimens are studied. The perfo- rmances were studied by means of sintering performance,XRD and DTA-TG.The results indicate that:(1) Vacuum training process is introduced into alumina production process, in the production process, we should take into account of moisture, vacuum mud training machine design and pump selection of exports. Bauxite powder is suitable for using vacuum-pumping process and has good plasticity. Vacuum de-airing extruder can improve the utilization andpowder sintering performance. Increasing vacuity can improve the property of specimens.(2) The performance of bauxite-based sintered corundum has relation with the type of alumina,sintered temperature and holding time. The density and porosity rise with the improvement of sintered temperature and holding time. The specimens with density of 3.62g·cm-3 and 3.65 g·cm-3 can got at the situation of vacuum-pumping at 0.095MPa and sintered at 1600℃for 9h.(3) The density and porosity of the bauxite-based sintered corundum rise with the improvement of sintered temperature and holding time. The amount of corundum rise with the descrease of particle size distribution of aluminum hydroxide. In order to produce bauxite-based sintered corundum,we should control the particle size distribution at 5μm.(4) The activation energies of every specimens show the the aluminium hydroxide is suitable for product bauxite-based sintered corundum,but the data ofα-alumina is not corrected with the experiment,which should be discussed later.