【作者】 刘松利；

【导师】 白晨光；

【作者基本信息】 重庆大学 ， 冶金工程， 2010， 博士

【摘要】 我国攀枝花-西昌地区的钒钛磁铁矿是一种铁、钒、钛等多元素共生的复合矿,具有很高的综合利用价值。现有的高炉冶炼、转炉提钒和钛精矿选矿处理钒钛磁铁矿工艺,仅利用了铁的68%、钒的47%、钛的15%。资源浪费巨大,并造成环境污染、土地破坏、生态失衡等严重问题。为了实现铁、钒、钛等资源高效清洁分离及综合回收利用,近年来转底炉煤基直接还原-电炉熔分技术逐步发展成为了处理钒钛磁铁矿的工艺之一,此工艺具有以煤代焦、还原温度高、冶炼时间短、能耗低、环境污染小和投资省等特点,符合我国资源、能源实际,成为目前国内外钢铁界研究的热点之一。本文为该工艺的应用基础研究,目的是充分地掌握钒钛铁精矿内配碳球团直接还原-熔分的工艺参数、反应机理以及工艺应用所需要的一般性条件。因此通过实验室压片机压球工艺、实验室竖式还原炉直接还原工艺和实验室高温快速加热炉熔分工艺的研究模拟出钒钛铁精矿直接还原-电炉熔分工艺参数。实验室压片机压球结果表明:使生球落下次数较高的条件分别为矿煤粒度比为(200:60)、球团水分为8%、粘结剂浓度为0.3%、压团压力为10 Mpa;球团水分是影响球团性能或压团工艺参数的主要因素,矿煤粒度比对球团性能有较大影响,压团压力和粘结剂浓度对各项指标的影响最小;生球团要进行干燥处理,干燥温度为105℃,干燥时间控制在2小时左右,所得球团的抗压强度为98N/个、高温爆裂性能小于20%,能满足转底炉直接还原工艺的要求;钒钛铁精矿直接还原-电炉熔分实验室模拟结果表明,配碳比(1.5:1)、还原温度(1350℃)、添加剂(2%)、还原时间(20min)时,球团金属化率可以达到88%以上;金属化球团电炉熔分工艺参数为碱度值1.4、熔分时间120min、熔分温度1450℃及配碳比1.5时,渣相中FeO含量为8.35%,能使铁和钒钛进行有效分离。然后采用热重实验、热力学、动力学计算模拟以及XRD、SEM、TG-DSC等检测手段对钒钛铁精矿的还原机理和熔分机理进行了详细研究。结果表明,钒钛铁精矿的还原历程依次为Fe2TiO4和Fe3O4、3(Fe3O4)?Fe2TiO4、Fe3O4?Fe2TiO4、Fe2TiO4和FeO、Fe和FeTi2O5;在磁铁矿大量还原生成浮士体的阶段,钛铁矿与新生成的浮士体发生“钛铁晶石化”,最终还原转变为单质铁和含铁黑钛石;钒钛铁精矿内配碳球团直接还原过程可分为前期和后期两个阶段,前期为化学反应控制,反应活化能为73.17kJ/mol;后期为扩散控制,反应活化能为152.02kJ/mol。还原度随反应温度的升高而增大,后期反应速度小于初期反应速度;FeO含量在整个熔化分离过程中起着重要的作用,通过控制FeO含量可以使熔化分离达到良好的效果。最后又将实验室研究结果扩展到对辊压球机-直径2.3m转底炉-50KVA电弧炉对钒钛铁精矿煤基直接还原-熔分的扩大试验研究,得出该工艺是可行的。通过实验得到含TiO2为49%、V2O5为1.2%以上的富钛渣和低钒生铁,并对含钒富钛渣中钛和钒分离进行了初步探讨,实现了铁、钛和钒的综合回收。本研究的主要创新点表现在:(1)对钒钛铁精矿内配碳球团转底炉直接还原-熔分工艺进行了实验室模拟,得出了实验室工艺参数。(2)对钒钛铁精矿内配碳球团转底炉直接还原-熔分机理进行了系统研究,为该工艺产业化奠定了理论基础。(3)采用对辊压球机-直径2.3m转底炉-50KVA电弧炉对钒钛铁精矿煤基直接还原-熔分工艺进行了扩大试验,得到的工艺参数和调控方法为该工艺工程化设计提供参考和依据。(4)以含钒富钛渣为原料进行酸浸制取钛白粉是完全可行的,试制的钛白粉白度可以达到同类产品指标,但处理工艺较复杂,且消色力较低;含钒富钛渣中的V基本进入水解母液和洗液中,收得率可达到93%以上,可通过水解废液的处理实现钒的回收。更多还原

【Abstract】 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.更多还原