Study On Basic Theory And Process Of Vanadium Extraction From Hot Metal With Low Carbon And High Vanadium

Hot metal containing low carbon and high vanadium comes from the smelting of Vanadium titanite which is produced by the‘Rotary Kiln-Electric Furnace'process.Due to the selective reduction in the process,carbon content in the hot metal is only3.6 wt%,whereas its vanadium content is 1.2 wt%.In general,vanadium extraction processes for vanadium-beargin hot metal mainly include converter process,hot metal ladle process and shaking ladle process.The converter process is mainly used for smelting of hot metal containing high carbon?4.1⁴.3 wt%?and low vanadium?0.2⁰.5 wt%?,but research on vanadium extraction from hot metal with low carbon and high vanadium?LCHV hot metal?is extremely poor.As a result,this thesis researches the basic theory and smelting proces of vanadium extraction from the LCHC hot metal in combined blown converter and by which way the following conclusions is reached:?1?Activity of V₂O₃ in vanadium slag is calculated by the ion and molecule coexistence model,which shows that magnitude of the V₂O₃ activity in vanadium slag is 10^-7.The value increases with the content of FeO,SiO₂,TiO₂ or Cr₂O₃ in the slag and the increase in temperature leads to higher value of V₂O₃ activity.?2?A coupling dynamic model is established to simulate the dynamic characteristic of vanadium extraction process in combined blown converter.The model consists of oxygen transfer model and slag-metal interfacial reaction model.Influence of amount of the cooling pellets on vanadium extraction process is simulated by this model,which shows that optimal amount of cooling pellets is 50kg/?t·Fe?.?3?Thermal simulation experiments are conducted in combined blown furnace to simulate vanadium extraction process of LCHV hot metal.Top blowing intensity in the experiments is 2.0 Nm³/?min·t?and bottom blowing intensity varies from 0 to 0.1Nm³/?min·t?.The result of the experiments shows that vanadium content in semi-steel is reduced to be 0.018⁰.078 wt%after 9 minutes'smelting and the corresponding vanadiun oxidation rate is 93.2⁹8.4%.Carbon content in semi-steel is 1.9².7 wt%and superheat degree of semi-steel is 14.28¹5.42%.In addition,vanadium distribution ratio is 368⁸28.V₂O₃ content in vanadium slag is 14.28¹5.42%and total iron content is 40.11⁵5.01%.?4?Carburization process of LCHC hot metal is researched through lab-scale experiments and thermal simulation experiments.Five carburants,namely,low nitrogen carburant,graphite,anthracite,carbon particles,and coke,are used in the lab-scale experiments at temperature of 1450?,1500?and 1550?respectively.Results of lab-scale experiments show that low nitrogen carburant is the most efficient carburant whose carburization amount and yield rate is 1.51 wt%and 80.2%respectively at temperature of 1500?.Anthracite is the most cost-effective carburant and its carburization amount and yield rate is 1.03 wt%and 55.7%respectively at temperature of 1500?.Therefore,thermal simulation experiments are done in which anthracite is used for carburization of LCHC hot metal.Result of the experiment shows that optimal amount of anthracite is 20kg/?t·Fe?.?5?Vanadium extraction experiments of carburized hot metal are conducted in combined blown induction furnace.Result of the experiments shows that superheat degree of semi-steel increases by 80?compared with the experiments of LCHC hot metal.What is more,the slag quality is greatly improved.V₂O₃ content in the slag increases by 8.3 wt%and total iron content decreases by 10.7%.?6?Viscosity-calculating model is established.It is demonstrated from the calculation result that viscosity of the vanadium slags at blowing end varier from 0.20to 7.35 Pa·s.The viscosity increases with V₂O₃ content and decreases with percentage of FeO or MnO in vanadium.In addition,solubility-calculating model is also obtained.It shows that the solubility of V₂O₃ in vanadium slag is 9.43%²5.71%.