Study On The Carbon Thermal Reduction And Aluminum Thermal Strengthening Of Vanadium-titanium Magnetite Concentrate

Panzhihua area stores rich vanadium titanium magnetite resources.The current processing of vanadium and titanium magnetite concentrate is mainly through the production process of vanadium-titanium magnetite concentrate-converter steelmaking process.This process titanium enters high furnace slag,basically cannot recycle.Cause titanium resource to waste huge.Therefore,it is of great significance to develop new technology and realize efficient separation and comprehensive recovery of iron,vanadium and titanium.The direct reduction process of rotary bottom furnace is characterized by high reduction temperature,short heating time,relatively static furnace material and the bottom of the furnace.In recent years,it has become one of the processing technologies of vanadium titanium magnetite concentrate.Due to the inconsistency of secondary oxidation and reduction rate due to the use of thick material layer operation,only thin layer operation can be carried out,resulting in low production capacity.Therefore,the reduction of the middle and lower pellets is the key to the direct reduction process of vanadium titanium magnetite concentrate.Using isothermal reducing experiment method of vanadium titanium magnetite concentrate carbon thermal reduction behavior are studied,and analyzed the temperature and reduction time of vanadium titanium magnetite concentrate pellets containing carbon reduction in the process of the influence of the phase transformation process.The experimental results show that:?1?in the temperature of the study,there are five stages in the reduction process of vanadium titanium magnetite concentrate.At the first stage??830oC?:It is mainly the precipitation of moisture and volatilization in coal powder.At the second stage?830oC⁹60oC?:the main reaction is the solid-solid reduction reaction of coal powder and vanadium titanium magnetite concentrate.At the third stage?960oC¹170oC?:at this temperature,the gasification reaction rate of carbon is accelerated,and the concentration of CO increases,which directly leads to the increase of gas-solid reaction rate.At the fifth stage??1380oC?:When reduction temperature reaches1480oC,the reduction reaction has been basically ended,and can be deduced that the stage of the reaction could be a few ferrous-pseudobrookite reduction of titanium ore of Ti O₂.?2?The phase transition in the process of carbon thermal reduction of vanadium titanium magnetite concentrate was obtained.Examines the reduction temperature 1250oC,1300oC and 1300oC respectively phase change in the 12 min.In 1350oC isothermal reduction process,after the completion of the reduction phase is metallic iron?Fe?,rutile?Ti O₂?and ferrous-pseudobrookite?Fe Ti₂O₅?.The final phase composition of vanadium titanium magnetite concentrate was not changed after adding aluminum powder.The carbon thermal reduction of vanadium titanium magnetite concentrate is strengthened in situ by using aluminum powder additive.The results show that:?1?the aluminum powder additive can effectively strengthen the reduction process and accelerate the carbon thermal reduction rate of vanadium titanium magnetite concentrate.?2?In aluminum heat strengthening reduction vanadium titanium magnetite concentrate carbon thermal reduction process,the part replace carbon as the reducing agent to participate in the aluminum reduction,due to the aluminum thermal reduction reaction is a strong exothermic process,leading to a rapid rise in the temperature of reaction around the interface,speed up the metallic iron particles gathered grew up in the pellets.The kenitics of carbothermic reduction of vanadium-titanium magnetite concentrates under isothermal and non-isothermal heating conditions are study by non pattern conversion method.Experimental results show that:The heating rate is higher,the conversion rate of vanadium titanium magnetite concentrate is lower at the same reaction temperature.In the whole process of non-isothermal reduction,activation energy changes with the change of conversion rate throughout the reduction process.The activation energy of the aluminum powder samples is less than that of the samples without aluminum powder.When the reaction temperature is less than 950oC,before this phase are controlled by the carbon gasification reaction rate,When the temperature is more than 1000oC,this one phase reaction is controlled by iron oxide reduction reaction.The reaction gas is difficult to reach the reaction interface,and the total reaction rate is controlled by diffusion.Therefore,activation energy increases gradually.