A Study On The Manufecture Of Magnesia Spinel Bricks For Large Dry-process Cement Rotary Kiln

Taking fused magnesia, fused spinel and sintered spinel as raw material and titania as additives,the specimen of magnesia spinel bricks were prepared through the production processes of mix, mould pressing and sintering.The properties of the bricks were studied by means of chemical analysis, XRD, SEM, EDAX, and so on.The relationship between spinel content, additives and their content, the synthesis of the spinel and the phase composition, sintering behavior, mechanical properties, refractoriness under load, thermal shock resistance, microstructure of the bricks were discussed. The results show that:(1) The bricks with high resistance to thermal shock could be achieved by increasing spinel, but the mechanical properties of the bricks at room temperature and high temperature would be low while the porosity and the bulk density of the bricks are affected slightly.(2) Although the thermal shock resistance of the bricks is improved, physical properties change slightly and mechanical properties reduce with the increase of spinel content and the introduction of Fe₂O₃ .It can be predicted that the bricks with a define amount of Fe₂O₃ will have an improved performance because there will be a small amount of liquid in the bricks which releases the thermal stress arised in the lining and brings forth a good adherance to the cement clinkers.(3) The well-sintered sample with improved mechanical properties and thermal shock resistance could be obtained by adding an appropriate amount of titanium oxide ,which is low in refractoriness under load.(4) The properties of samples were changed slightly by using either fused spinel or sintered spinel as one of the raw materials.