Research On The Yield Improvement Of Ferrovanadium Smelting In Large-scale Tipping Furnaces

Ferrovanadium is a commonly used additive for iron and steel alloying elements.Adding a small amount of ferrovanadium can improve the toughness,strength and wear resistance of iron and steel materials,so it has been widely used in machinery manufacturing,construction,aerospace,railway construction,bridge laying and other industries.The main raw materials for ferrovanadium production are V₂O₃ and V₂O₅.The smelting method generally adopts the electrothermite method.The commonly used smelting equipment at home and abroad is the vertical drum furnace with a single furnace capacity of 2-3 tons.This paper mainly studies the large-scale tipping furnace smelting process with a higher single furnace capacity,and its capacity can reach 6-8tons.Based on the principle of ferroalloy smelting by electro-aluminothermic method,the production process characteristics of ferrovanadium smelting by mixing V₂O₃ and V₂O₅ were studied.The influence rules of various process conditions on process indexes were found out,and better process control parameters were obtained,which were used to guide production.Specific research contents are as follows:(1)Al₂O₃-Ca O-Mg O ternary smelting slag system was studied.Thermodynamic analysis showed that the low melting point composition range of the slag system was w(Ca O)=30%?50%,w(Mg O)=0?10%,w(Al₂O₃)=40%?60%.Compared with the theoretical low melting point composition region and the actual smelting slag composition region,it was found that reducing the Mg O content in slag and increasing the Ca O content were the available ways to reduce the melting point of the slag system.The slag balance analysis and the heat demand analysis of ferrovanadium smelting were also carried out.The contents of Al₂O₃ and Mg O in the three slags during the ferrovanadium smelting process and the heat demand in the smelting process were determined.(2)The effects of different vanadium oxide ratios on vanadium yield were studied.The results show that increasing the ratio of V₂O₃ with higher vanadium content can effectively reduce Vanadium Loss from slag.However,with the increase of the ratio of V₂O₃ to V₂O₅,the total time required for smelting will be longer,the energy consumption will increase and the smelting efficiency will decrease.Considering comprehensively,when the ratio of V₂O₃ to V₂O₅ is 5:2,it is an ideal control parameter.(3)The effect of aluminium ratio on vanadium yield was studied.With the increase of aluminium ratio,the content of TV in lean slag decreased obviously.Corresponding to each aluminium distribution coefficient,there is basically a limit value of lean slag.At this time,the further lean slag space is not large,and the aluminium distribution coefficient of 1.25 is more reasonable under the current conditions by prolonging the power-on time or increasing the furnace temperature.(4)Experiments on slag-rich refining have been carried out.The results show that the power-on time of slag-rich refining is prolonged by 65 minutes compared with that of normal refining.The vanadium content in slag decreases and the recovery rate of ferrovanadium is effectively improved.The comprehensive recovery rate reaches 96.2%.The experimental results are obvious.