Research On The Corrosion Mechanism Of Magnesia-carbon In Vanadium Slags

Titanomagnetite, containing massive vanadium resource, is the mainly source of initial vanadium products. Converter vanadium recovery is a main method to produce vanadium, which is to gain the slag containing V₂O₃ by oxidize the iron liquid, produced by blast furnace, containing V in converter. Compared to ordinary slag, converter vanadium recover-slag has the character of"high oxidizability","high level of vanadium","low viscosity","low basicity". To meet the requirement of converter vanadium recover and improve the production benefit, the MgO-C brick, which has the performance of excellent thermal shock resistance and slag erosion resistance, are used as the lining. However, field production find that the life of MgO-C, linning life is 8000 times, brick in converter vanadium recovery is short than the life, linning life is 10000 times, in general steel-making. Hence, researching the corrosion mechanism of MgO-C brick has great significance on improving the life of MgO-C brick, optimizing converter vanadium recovery technology, improving economic benefit.This paper research the effects of composition variation of converter vanadium recovery-slag, variation of rotation speed, variation of carbon content in MgO-C brick, thermal shock, cathodic protection on the corrosion of MgO-C brick at 1380℃, and the properties of converter vanadium recovery-slag; Following conclusions can be drawn by making investigation on the microstructure of worn samples, SEM-EDS analyses, thermodynamic calculation and analyses on the character of converter vanadium recovery-slag.â‘ It is can be found that the higher the V₂O₃, TiO₂, MgO are, the higher the melting point, more FeO, MnO in slag could decrease the melting point; with increasing the content of V₂O₃, MgO, the viscosity go high, and high level content of FeO,MnO,TiO₂ could decrease the viscosity by studying on the properties of converter vanadium recovery-slag. Higher contents of FeO,TiO₂,MnO in converter vanadium recover-slag could enhance the corrosion rate of MgO-C brick samples, on the contrary, higher contents of V₂O₃,MgO could decrease the corrosion rate, compared to other compositions, the effect of TiO₂ is significant.â‘¡Research the effect of vanadium recovery temperature, composition of slag, the relative speed between samples and slag, the content of C in samples on the corrosion rate, at dynamic conditions. The corrosion rate were evaluated by the variation of the sampls'quality, the corrosion rate equations were geted.â‘¢The wear mechanism of C and resolution mechanism of MgO grain in MgO-Cbrick were analysed by SEM-EDS investigation and the Factsage calculation.â‘£Due to the MgO grain suffer the thermal shock, which result in accelerating destruction, the corrosion rate raised, and the C also affected at thermal shock condition. Rejecting the ions which could erode the carbon by cathodic protection, it can improve the slag resistance of MgO-C brick efficiently by analysis the composition of the slag after test.