The Research Of The Zirconia Toughened Corundum-Spine Castables

The new dry process cement rotary kiln outlet and burner is under of the harsh environment ,and the use of existing refactory is not satisfied . so the aim of this research is to study a new type of material , Corundum-Spine Castable, for cement rotary kiln's outlet and burner. Further, the ZrO2's effect on thermal shock resistance of Corundum-Spine castable is studied.During the study subjects , first, adjust the content of each component in the matrix to get the best performance of refactory. The study found that In high-temperature heat treatment process MgO and Al2O3 micropowder react and generate spinel. The reaction starts from 1100℃and finishs to 1300℃. From 1300℃to 1500℃, spine grain grows. So the content of MgO will decide the overall performance of materials. the study is found that the best content of MgO is 9wt%, at this point , the performance of refactory is best, such as linear expansion rate, strengh and alkali resistance. 1wt% SiO2 is added to the matrix to increase the fluidity of material and to accelerate sintering. The binding system of MgO and SiO2 can supply better strengh at low temperature, middle temperature and high temperature, so the no-cement castable can be developed and the CaO effect on the performance of refactory can be removed. The third-generation high-performance admixtures PC is used to improve the fluidity of refactory.In order to improve the thermal shock resistance of Corundum-Spine castable, the effect of ZrO2 added to Corundum-Spine castable is studied. The study result is that added ZrO2 to Corundum-Spine castable can improve markedly the thermal shock resistance of castable, and the Flexural Strength retention rate K is improved from to 83%. The ZrO2 toughening mechanism is: 1.microcrack toughening: ZrO2 Martensite phase transformation; 2. dispersion toughening: ZrO2 as Second Phase Particle. And the best ZrO2 addition is 6wt% and the best particle size is d50= 300μm. At the same time, the relationship between the elastic modulus E and the thermal shock performance is studied. The study found that Elastic modulus E and the thermal shock performance is the inverse . With the increase in the number of the thermal shock tests, Elastic modulus E of Corundum-Spine castable reduce gradually. So Elastic modulus E can become evaluation index to evalue the thermal shock resistance of Corundum-Spine castable. And by testing the castable's E, the material damage degree can be assessed.Finally, a new type of refractory, the Zirconia Toughened Corundum-Spine Castables, is be developed successfully, and is producted industrily. The new castables have been used in the HeNan HongChang Cement 4500T/d Production Line and the use result is fne so far.