Corrosion mechanism of TiC-containing slag to MgO-C bricks
To effectively recover titanium resources and meet the requirements of the high temperature car-bonization-low temperature chlorination process to refractories,the corrosion mechanism of TiC-containing slag to MgO-C bricks during high-temperature carbonization process was analyzed through thermodynam-ic calculations,XRD and SEM.The thermodynamic calculation results show that:(1)the higher the temper-ature,the stronger the corrosion ability of the slag;below 1 560 ℃,the slag reacts with MgO-C bricks to generate high melting point phases such as MgAl2O4,Mg2SiO4,and MgTi2O4,which slow down the corro-sion rate of MgO-C bricks;however,at above 1 560 ℃,the high melting point phases generated in the early stage gradually dissolve,thereby intensifying the corrosion to MgO-C bricks;(2)as the carbonization reaction progresses,the TiO2 content in the slag decreases,while the TiC content gradually increases,and the corrosion of the slag to MgO-C bricks gradually weakens.According to the microstructure analysis of the used MgO-C bricks,the corrosion mechanism of MgO-C bricks is that O2 in air reacts with graphite forming pores;TiO2 and SiO2 in the slag react with MgO and the matrix of the brick to form high-tempera-ture intermediate phases first,and as the reaction progresses,low melting point phases form,leading to the gradual corrosion of MgO-C bricks.
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