Basic Research For Vanadium Titano-magnetite Extracted By Rotary Kiln Pre-reduction And Full Oxygen Bath Smelting Process

Vanadium titano-magnetite is a typical multi metal co associated ore.Vanadium and titanium are important strategic resources.Although the traditional blast furnace can extract iron and vanadium from the vanadium titano-magnetite,but a large amount of titanium resources can only be found in the form of titanium bearing blast furnace slag.It has caused great waste of titanium resources.Therefore,in order to comprehensively recover iron,vanadium and titanium,it is urgent to develop new smelting process which can achieve scientific utilization of the strategic resources of vanadium and titanium.Aiming at the problem that the smelting of vanadium titano-magnetite in blast furnace needs to be added with ordinary ore and the TiO₂ content in slag is too low to be used,a new process of rotary kiln pre-reduction and full oxygen bath smelting process is put forward.Combined with differential thermal analysis,chemical analysis,XRD diffraction analysis,scanning electron microscopy,energy spectrum analysis and so on,the pre reduction experiment of vanadium titano-magnetite by rotary kiln,the composition and property simulation of smelting slag,the iron and slag separation experiment,the mathematical model of full oxygen of short ironmaking process were carried out.The research results provide design parameters and technical support for industrial test.The pre reduction experiment of vanadium titano-magnetite showed that increasing the reduction temperature could significantly increase the pre reduction metallization rate,but the high reduction temperature was easy to cause the powder sticking.The coal with ash melting point higher than 1300?is used.under the condition of more than 30%coal adding,12%CaO adding,reduction temperature of 1050?,heating time 120 min,reduction time 120 min,vanadium titano-magnetite metallization rate can reach 80.12%.The reduction powder no sticking,and it can prevent rotary kiln from forming ring.The simulation results of vanadium titano-magnetite extracted by full oxygen smelting process show that when the melting temperature higher than 1450?,slag basicity increased from 0.27 to1.1,the slag has good fluidity,the TiO₂ content has a little influence on the fluidity of slag.The final slag basicity and the carbon content of molten iron will affect the sulfur distribution ratio between slag and iron.When the final slag basicity is 1.1 and the carbon content of molten iron reaches over4%,the sulfur distribution ratio between slag and iron is about 6,which is close to the blast furnace process.The FeO in the slag and the CO₂ in the gas can inhibit the formation of Ti?C,N?in the slag,so as to realize the smelting of all vanadium titano-magnetite.The experimental results show that the vanadium titano-magnetite can be successfully extracted to obtain molten iron when the final slag basicity is 1.1,the melting temperature is 1500?,the melting time is 30 min and the pulverized coal addition is 22%.The TiO₂ content of the slag can reach more than 36%.However,the content of C in molten iron is 1.78%and the content of S is 0.23%.The hot metal needs pretreatment desulfurization.The phase of the slag is mainly in the form of CaTiO₃ and complex compounds of?Mg₄Ti₂?Ca₂(Al₄Si₂O₂₀),and there is no detection of the existence of TiC phase.The calculation results of the mathematical model of full oxygen of short ironmaking process shows that If the metallization rate of pre reduction burden increased by 5%,the coal consumption of full oxygen smelting furnace could be reduced by 33kg/tFe,and the oxygen consumption could be reduced by 30m³/tFe.With the increase of the gas oxidation rate of the furnace,the coal consumption can be reduced by 59kg/tFe,and the oxygen consumption can be reduced by39m³/t Fe.When the oxygen content of blast air increases by 2%,the coal consumption can be reduced by4kg/tFe and the oxygen consumption is reduced by about 12m³/tFe.Vanadium titano-magnetite is extracted by full oxygen bath smelting process.Coal consumption is 825kg/tFe.Oxygen consumption is 364m³/tFe.The Rotary kiln can produce 2648m³/tFe of the tail gas with calorific value of 2542kJ/Nm³.There are three innovations of this paper include.First,a new process for smelting vanadium titano-magnetite by rotary kiln pre-reduction and full oxygen bath smelting is proposed.Second,the reaction thermodynamics of the formation of Ti?C,N?in the slag and the inhibition effect of FeO and CO₂ on the formation of Ti?C,N?in the slag are revealed.It shows that full oxygen bath smelting process can control the slag of FeO and gas oxidation degree to inhibit the formation of Ti?C,N?.Third,a mathematical model of rotary kiln pre-reduction and full oxygen bath smelting process has been established.The relationship between pre reduction metallization,gas oxidation degree and blast oxygen content on energy consumption has been analyzed.