Thermodynamic And Macro-kinetic Studies On Oxidations Of Carbon And Vanadium During Vanadium Extration By Converter

The vanadium and it’s products have very important and extensive use in industry,and the vanadium resource is one kind of strategic resource for a morden industrialcountry. Abundent reserves of vanadium titano-mangnite, of which the vanadium（V₂O₅）content is61%of the proved reserves in the whole country, is stored in Pan Zhi Huaarea. The Pan Steel Co. adopts converter vanadium extraction process to extractvanadium from hot metal bearing vanadium. The primary goal of the process is toextract and enrich vanadium maximumly from hot metal containing vanadium, and alsoprevent the carbon in hot metal from being overoxidized at the same time. Hence, thestudy on oxidations of carbon and vanadium during vanadium extration by convertershould be quite significant for the actual prouction process. The previous relevantresearch on oxidations of carbon and vanadium during vanadium extration by convertermainly focus on the calculations of critical tempereature of selective carbon-vanadiumoxidation. However, for one thing, the kenetic studies on the the oxidations of carbonand vanadium kenetics during vanadium extraction by converter process and studies onvanadium distribution behavior at end point of the process is quite few. Moreover, themeaning of the critical tempereature of selective carbon-vanadium oxidation is limited.So, the law of the oxidations of carbon and vanadium would be systematically studidedfrom the perspective of classic chemistry thermodynamics and macro-keneticsrespectively.The slag thermodynamic model of vanadium slag was established according to thecoexistence theory and the electronic theory of slag structure based on the classicchemistry thermodynamics. Then, the influences of the vanadium slag composition andtemperature on the distribution behavior of V between slag and semi-steel at the endpoint of vanadium extraction by converter were studied by experiments and calculations.The results showed that, the content of V usually ranged from0.02%to0.06%insemi-steel, increased with increasing of temperature and the concentration of V₂O₃,SiO₂and TiO₂, but decreased with increasing of FeO concentration in the slag. Thedistribution ratio of V between slag and metal phase was in the range of100to500,decreased with higher temperature and the concentration of SiO2, TiO2and increasedwhile the concentration of FeO in the slag increased. It exists a critical V₂O₃contentthat makes the distribution ratio of V between slag and metal phase reached maximum, the theoretical results of the critical content is23.77%, but the experimental one isbetween15%and20%.The law of the oxidations of carbon and vanadium under the conditions withdifferent initial iron compositon, tempereature and oxygen supplement were studied byexperiments and calculations, based on the coupled reaction kinetic model ofmulti-conponents, from the maro-kinetic perspective. The results showed, the elementsSi and Ti which have strong affinity with oxygen strongly inhibited the cabon andvanadium from being oxidized, and it quickly became stronger when the Si and Ticontent in hot metal. Besides the content of Si and Ti in the metal, the iron compositonand temperature had little influence on the oxidations of Si and Ti. The carbon and otherelements oxidation rate had small change when the initial carbon content increase from4.36%to4.8%. The vanadium oxidation rate increase when the content of itself in hotmetal increase from0.3%to0.5%, as the other elements had no obviously change. Inthe temperature interval of1375℃to1425℃, the carbon oxidation rate was verysensitive to the temperature change, the carbon and vanadium oxidation rates inceareseand decrease substantially when the tempreature increase.