| Vanadium and titanium iron concentrate of Panzhihua–Xichuang in our country is one kind of iron, vanadium, titanium multiple-element symbiotic composite ore, has extremely high comprehensive utilization value.The current process on dealing with vanadium and titanium magnetite craft processing of blast furnace, converter v-recovering and titanium concentrates dressings only make use of 68% iron, 47% vanadium and 15% titanium. The waste of resources are huge and cause serious problems such as environmental pollution, land damage, ecological unbalance and so on.In order to realize efficient cleaning separation and comprehensive recycling of iron, vanadium, titanium resource etc, the direct reduction technology of RHF based coal and melting and separation technology of arc furnace in recent years gradually becomes one of best processing technology of vanadium, titanium magnetite .The technology has many features such as using coal replace coke, high temperature, short time of smelting, low energy consumption , environmental pollution and investment. The technology is in accordance with the characteristics of energy resources and is becoming one of the hot spot research of iron steel in our world.The present work mainly concentrates on a application fundamental study on the direct reduction technology of RHF based coal and melting and separation technology of arc furnace .The purpose is fully grasping process parameters , reaction mechanism and application technology of the general conditions needed of the technology . In order to simulate process parameters of the new technology , pressing pellets by laboratory preforming machine has been investigated,as wellas reduction process by laboratory vertical reduction furnace and melting-separation by laboratory rapid heating process furance. Research results of laboratory preforming machine show that conditions on higher falling number of raw pellets respectively are that mine and coal size ratio is 200:60,moisture is 8%,binder is 0.3% ,pressure is 10 Mpa.The main factors of affecting pellets performance or briquett process parameters are respectively pellets moisture, mine and coal size ratio , pressure and binder concentration.Raw pellets must be processed by drying.when the drying temperature is 105℃,the drying time is controled in 2 hours. The compressive strength of the pellets is 98N/a, high temperature burst performance of the pellets is less than 20%,which can meet the requirement of direct reduction process by rotary hearth furnace . The experimental results of reduction process by laboratory vertical reduction furnace show that a metallization rate of 88% was achieved while the pellets are in carbon and Oxygen ratio(1.5:1), reaction temperature(1350℃), additive(2%) and reaction time(20min). The experimental results of FeO melting -separation by laboratory rapid heating process furance show that content of FeO in slags is 8.35% while alkalinity is 1.4,melting time is 120 min,melting temperature is 1450℃and carbon ratio is 1.5, Can make iron , vanadium and titanium effectively separated.Then ,through the thermogravimetric experiment, thermodynamics and kinetics calculation simulation and XRD, SEM and TG - DSC etc ,direct reduction mechanism and melting -separation principle of vanadium and titanium concentrate are studied. The thermogravimetric experimental results show that reduction process on quick reduction of vanadium and titanium iron concentrate of carbon-containing pellets respectively is Fe2TiO4 and Fe3O4,3(Fe3O4)?Fe2TiO4,Fe3O4?Fe2TiO4,Fe2TiO4 and FeO,Fe and FeTi2O5 .In the stage of generating float by magnetite iron reduction, generate the new phase of Fe2TiO4, and finally vanadium and titanium iron concentrate is reduced into Fe and (Fe,Mg)Ti2O5. The experimental results of kinetics calculation simulation show that the reduction process on vanadium and titanium iron concentrate pellets containing carbon can be classified into two stages. The initial stage is controlled by chemical reaction between the metal oxide and carbon,and the activation energy of the reduction process is 73.17kJ/mol.The following stage is controlled by the diffusion of reduced products,and the activation energy of the reduction process is 152.02kJ/mol. Reductive degree rises with the increase of temperature. Later reaction velocity is less than initial reaction velocity. FeO content plays an important role in melting separation process .Through controling FeO content can make good effect to melting separation. Finally, laboratory findings have been expanded on roll squeezer, RHF of 2.3 meters diameter and 50KVA arc furnace. Process parameters have been obtained. The technology is feasible. Through the experiment titanium slag that TiO2 is 49% and V2O5 is 1.2% and iron of low vanadium are obtained, can satisfy the subsequent processing quality requirements. Titanium slag containing vanadium was discussed to separate vanadium and titanium,finally comprehensive recovery of iron, titanium and vanadium has been achieved. The main new view points of the author are as follows:(1) Through laboratory simulation on direct reduction technology based coal and melting and separation technology , get the laboratory process parameters. (2) Direct reduction mechanism and melting -separation principle of vanadium and titanium concentrate are studied,which lay a theoretical foundation as industrialization.(3) Exploratory testings are studied by roll squeezer, RHF of 2.3m diameter and 50KVA arc furnace ,get process parameters and results ,which provides reference and basis for the engineering design.(4) Titanium slag containing vanadium as raw material for acid leaching is feasible to obtain titanium dioxide, titanium dioxide trial whiteness index of similar products can be achieved, but need more complex treatment process, and reducing color power is low.Vanadium basic has get into hydrolysis mother liquor and lotion intorich , the recovery rate could reach 93% or more, recovery of vanadium can be achieved by treating those waste water.
|
PDF Full Text Request