Study On The Synthesis Of Calcium Hexaluminate And Mechanism Of Its Interaction With Slag

Calcium hexaluminate（CA₆）material has the characteristics of high refractoriness,low thermal conductivity and low solubility in the slag containing iron,so that it can be used in the part of the steel bag wall which is in direct contact with molten steel.With the increasing demand for smelting in the steel industry,the production of clean steel has become even more important,so research on low-carbon and carbon-free refractories has become particularly important.CA₆ refractories have low wettability,high resistance to alkali corrosion and slag of molten nonferrous metals（particularly aluminum）and is suitable for cement kiln and aluminum smelting industry.Therefore,it is necessary to study the performance of CA₆ and the mechanism of slag corrosion resistance,which is important for improving ladle life,developing new non carbon refractory material and reducing production cost.In this paper,calcium carbonate and activated alumina were used as raw materials to synthesize CA₆.The effects of different additives on their properties were studied.The slag corrosion resistance of CA₆ and different magnesia refractories was studied by static crucible method.The corrosion resistance mechanism of different materials was analyzed by XRD and SEM.The corrosion resistance mechanism of different materials was analyzed by XRD and SEM.The results show that the addition of TiO₂ can obviously promote the sintering of samples,decrease the apparent porosity,and increase the compressive strength at normal temperature.The volume density increases with the increase of the addition;The addition of Y₂O₃ resulted in the high melting point phase of yttrium aluminate(Al₅Y₃O₁₂),which was attached to the surface of the CA₆ flaky structure.After adding ZrO₂,it did not participate in the reaction but existed in the pores alone,both of which had no effect on the physical properties of the samples at room temperature;After adding CA₆ with different additives,CA₆ increased the viscosity of slag most,and the effect of adding TiO₂ on the viscosity of slag was the least.Without any additives CA₆ on slag corrosion resistance is best,and the addition of TiO₂ additive slag permeability resistance is the worst;CA₆ and other magnesia material mixed with slag,CA₆ can significantly improve the slag viscosity,in the static crucible experiments,slag resistance of the CA₆ products is the best.Magnesium iron brick anti-iron slag good erosion,slightly worse than magnesium bricks,and magnesium and aluminum brick corrosion resistance is poor.