STUDY OF SMELTING REDUCTION RATE FOR VANADIUM TITANIUM MAGNETITE

A comparative study was made of the reduction kinetics for high temperature smelting of vadium-titanium-containing magnetite,together with Hainan iron ore,using iron bath method.Three peaks were revealed on the reduction rate curves for the magnetite,while one peak only for Hainan ore.Under the same conditions,the smelting reduction rate of the magnetite was found to be lower than that of Hainan ore.The rate increases evidently with the increase of the bath volume.The expressions of smelting reduction rate were suggested for the reduction with and without iron bath respectively.

Effect of diboron trioxide on the crushing strength and smelting mechanism of high-chromium vanadium–titanium magnetite pellets

The effect of diboron trioxide(B_2O_3) on the crushing strength and smelting mechanism of high-chromium vanadium–titanium magnetite pellets was investigated in this work. The main characterization methods were X-ray fluorescence, inductively coupled plasma–atomic emission spectroscopy, mercury injection porosimetry, X-ray diffraction, metallographic microscopy, and scanning electron microscopy–energy-dispersive X-ray spectroscopy. The results showed that the crushing strength increased greatly with increasing B_2O_3 content and that the increase in crushing strength was strongly correlated with a decrease in porosity, the formation of liquid phases, and the growth and recrystallization consolidation of hematite crystalline grains. The smelting properties were measured under simulated blast furnace conditions; the results showed that the smelting properties within a certain B_2O_3 content range were improved and optimized except in the softening stage. The valuable element B was easily transformed to the slag, and this phenomenon became increasingly evident with increasing B_2O_3 content. The formation of Ti(C,N) was mostly avoided, and the slag and melted iron were separated well during smelting with the addition of B_2O_3. The size increase of the melted iron was consistent with the gradual optimization of the dripping characteristics with increasing B_2O_3 content.

Sintering behaviors and consolidation mechanism of high-chromium vanadium and titanium magnetite fines

To achieve high efficiency utilization of high-chromium vanadium-titanium magnetite （V-Ti-Cr） fines, an investigation of V Ti42r fines was conducted using a sinter pot. The chemical composition, particle parameters, and granulation of V-Ti-Cr mixtures were analyzed, and the effects of sintering parameters on the sintering behaviors were investigated. The results indicated that the optimum quicklime dosage, mixture moisture, wetting time, and granulation time for V-Ti-Cr fines are 5wt%, 7.5wt%, 10 min, and 5-8 min, respectively. Meanwhile, the vertical sintering speed, yield, tumbler strength, and productivity gains were shown to be 21.28 mm/min, 60.50wt% , 58.26wt%, and 1.36 t·m^-2·h^-1, respectively. Furthermore, the consolidation mechanism of V-Ti-Cr fines was clarified, revealing that the consolidation of a V-Ti-Cr sinter requires an approximately 14vo1% calcium ferrite liquid-state, an approximately 15vo1% silicate liq- uid-state, a solid-state reaction, and the recrystallization of magnetite. Compared to an ordinary sinter, calcium ferrite content in a V-Ti-Cr sinter is lower, while the perovskite content is higher, possibly resulting in unsatisfactory sinter outcomes.

Influence of Coke Content on Sintering Process of Chromium-containing Vanadium-titanium Magnetite

The sintering of chromium-containing vanadium-titanium magnetite using different coke contents was studied through the sintering pot tests, X-ray diffraction analysis and mineralogical phase analysis. Results showed that, as the coke content increased from 3.2% to 4.4%, the liquid phase and combustion zone thickness increased while the vertical sintering rate and ratio of sintered product decreased. In addition, the combustion ratio of exhaust gas also increased with increasing the coke content, indicating that combustion zone temperature also increased, and the excessive the coke content in the sintering process of vanadiumtitanium magnetite is harmful. As the coke content increased, the magnetite, silicates, and perovskite contents of the sintered ore increased while the contents of hematite and calcium ferrite of sintered ore decreased; drum strength decreased, and reduction degradation properties increased while reduction ability decreased. We found that the appropriate coke content for the sintering process is 3.6 wt%.

THERMODYNAMICS OF V REDUCTION IN SMELTING REDUCTION SLAG FOR V-Ti-CONTAINING MAGNETITE

For slag system of CaO-SiO_2-Al_2O_3-MgO-V_2O_5,the time of V reduction to appro ch the dynamical equilibrium is about 6 h,the equilibrium time is not evidently influenced by the ratio CaO/SiO_2 and shortens with the increase of temperature.It the ratio of the weight of slag to that of iron bath is 1/2,CaO/SiO_2 0.8 and tomperature 1773 K.the maxium distribution coefficeent of V reduction is 32.4 and maxium recovery of V is 96.1%.

重钢西昌矿业钒钛磁铁矿二段磨矿混合介质磨矿特征研究

重钢西昌矿业有限公司为了达到绿色节能的目的,针对钒钛磁铁矿二段磨矿中存在的矿物过磨与磨矿能耗高的问题,进行了钢球、瓷球、瓷球+钢球不同磨矿介质条件下的磨矿条件试验及能耗测试试验。试验结果表明:瓷球+钢球混合介质磨矿与现有钢球磨矿相比,试验室条件下混合介质磨矿产品中的-0.019mm粒级含量下降了1.21个百分点,混合介质磨矿能耗下降了16.35%,混合介质磨矿可有效减轻矿物的过磨并节约磨矿能耗,瓷球+钢球混合介质可取代钢球作为二段磨矿介质。

某铁矿尾矿中硫铁矿及伴生钴回收试验研究

为实现对攀西某钒钛磁铁矿选矿尾矿中硫、钴的高效回收,对其进行浮-磁联合回收试验研究。结果表明,磨矿细度为-0.074 mm占96.81%,矿浆pH值为4,捕收剂(丁基黄药和丁铵黑药,按质量比1∶1复配)用量为80 g/t,采用“1粗3精2扫”的闭路流程进行浮选试验,获得硫钴粗精矿,再对其进行磁选作业获得含37.71%硫、0.921%钴的高钴硫精矿和含33.18%硫、0.623%钴的中钴硫精矿产品。本研究不仅为钙化焙烧钒渣酸浸提钒-铵盐沉钒后的酸性废液提供了利用途径,也实现了该尾矿资源中伴生金属的高效回收。

钒钛磁铁矿尾矿废渣资源化利用现状及展望

随着钒钛资源的开发和利用,同时也产生了大量的钒钛磁铁矿尾矿废渣,需要占用大量土地用于堆放,既产生经济负担,又破坏了生态环境。目前,钒钛磁铁矿尾矿废渣的利用方式主要有两种,一是对尾矿废渣中有价值的元素进行提取回收,二是整体利用尾矿废渣制备建筑材料。如何最大程度对钒钛磁铁矿尾矿废渣进行资源化利用,提高其利用效率,保护生态环境,是值得深入研究的课题。

低品位钒钛磁铁矿绿色高效湿法处理研究进展

为了推动低品位钒钛磁铁矿的绿色高效利用,针对现有处理工艺存在的问题,从直接浸出、预处理—浸出以及浸出液净化除杂等方面总结了低品位钒钛磁铁矿湿法处理工艺的研究进展。通过分析指出,富氧碱浸—酸浸处理工艺能够产出氧化铁红、钒酸铵和富钛料,并能实现酸碱循环利用,为低品位钒钛磁铁矿的绿色高效利用提供了新的思路;氢还原—酸浸—萃取处理工艺具有高钒、高钛回收率及绿色环保的优势,后续能够产出高附加值的铁、钒、钛产品,是现有钒钛磁铁矿处理工艺的有效补充,值得在今后的研究与应用中给予重点关注。

High-Temperature Oxidation Behavior of Vanadium,Titanium-Bearing Magnetite Pellet

By means of isothermal oxidation and chemical analysis, great importance was attached to the parameters that made effects on the oxidation degree of vanadium, titanium-bearing magnetite pellet in high-temperature processing （1 073- 1 323 K）. Based on the experimental data, oxidation kinetics of pellet was analyzed according to shrinking unreacted-core model subsequently. Experiment results display that the oxidation degree of pellet increases with increasing of oxidation time, oxidation temperature and oxygen content, as well as shrinking of pellet diameter. Under the condition of oxidation time 20 min, oxidation temperature 1223 K, oxygen content 15%, and pellet diameter 12 mm, oxidation degree of pellet reaches 92.92%. The analysis of oxidation kinetics indicates that oxidation process of pellet is controlled by chemical reaction with activation energy 68.64 kJ/mol at a relatively lower temperature （1073-1 173 K）. Oxidation process of pellet is mixed-controlled by chemistry reaction and diffusion with activation energy 39.66 kJ/mol in the temperature range of 1 173-1 273 K. When oxidation temperature is higher than 1 273 K, the limited link of oxidation reaction is the diffusion control with the activation energy 20.85 kJ/mol. These results can serve as a reference to the production of vanadium, titanium-hearing magnetite pellet.

Influences of Technological Parameters on Smelting-separation Process for Metallized Pellets of Vanadium-bearing Titanomagnetite Concentrates

The smelting-separation process for metallized pellets of vanadium-bearing titanomagnetite concentrates was studied.The influences of smelting temperature,smelting time,and the basicity of the metallized pellet on vanadium and iron recovery were investigated.The characteristics of titanium slag were analyzed using X-ray diffraction,energy dispersive spectroscopy,and mineralographic microscopic analysis.The results demonstrate that appropriate increases in smelting temperature and smelting time can improve the vanadium and iron recovery from metallized pellets and are beneficial for the slag-iron separation.Although increasing the basicity of the metallized pellet can considerably improve the vanadium and iron recovery,the TiO;grade of titanium slag was decreased.Under the optimal conditions,90.17% of vanadium and 92.98% of iron in the metallized pellet were recovered,and the TiO;grade of titanium slag was 55.01%.It was found that anosovite,augite,spinel,glassiness,and metallic iron were the main mineral phases of the titanium slag.

Optimization of BF Slag for High Cr_2O_3 Vanadium-titanium Magnetite

In order to clarify the slag system of high Cr2O3 vanadium-titanium magnetite smelting in BF （blast furnace）, the melting properties of slag samples prepared by analytically pure reagents were measured. By means of orthogonal test synthetic weighted score method, the optimal slag for high Cr2O3 vanadium-titanium magnetite was obtained, which contained 10% MgO, 8% TiO2 and 15% Al2O3, with the binary basicity being 1.15. In addition, the effects of basicity, MgO, TiO2 and A12 03 on slag melting properties were investigated by single factor test, and the results showed that, with increasing the basicity or TiO2 content, melting temperature （Tin） increased, whereas initial vis- cosity （r/0） and high temperature viscosity （r/h） decreased. With increasing the MgO content, Tm decreased firstly and then increased. With increasing the Al2 O3 content, Tm increased, and η0 and r/h decreased firstly and then increased.

Oxidation Kinetics,Structural Changes and Element Migration during Oxidation Process of Vanadium-titanium Magnetite Ore

The oxidation kinetics, structural changes, and elements migration during the oxidation process of the va- nadium-titanium magnetite （VTM） ore were analyzed. Kinetics analysis indicated that the oxidation process was con- trolled by diffusion control and could be divided into interface diffusion and lattice diffusion with apparent activation energy of 99.69 kJ/mol and 144.08 kJ/mol in the range of 800--1000℃, respectively. The surface structure changed with the oxidization temperature as follows： dense surface→nano sized sheets→submicron particles→molten particles. The compact structure changed into porous one because of the elements migration and enrichment. Both Fe and Ti elements migrated in the opposite direction during the oxidation process. The V etement in the raw ore stably existed in the form of V^5＋ state, some vanadium migrated and occupied the tetrahedral sites of the hematite during the oxidation process.

Carbothermic Reduction Mechanism of Vanadium-titanium Magnetite

To achieve the high-efficiency utilization of vanadium-titanium magnetite（ VTM）,reduction experiments were conducted to determine the carbothermic reduction mechanism of VTM. Effects of volatile matter,temperature,time,and carbon ratio（ molar ratio of fixed carbon in coal to oxygen in iron oxides of VTM） on reduction degree were investigated.Results show that reduction degree increases with increasing volatile matter in coal,temperature,time,and carbon ratio.Phase transformation,microstructure,and reduction path were analyzed by X-ray diffraction,scanning electron microscopy,energy-dispersive X-ray spectroscopy,and Fact Sage 6. 0. The thermoravimetry-differential scanning calorimetry-quadrupole mass spectrometer method was used for kinetic analysis of the main reduction process. Results indicate that the kinetic mechanism follows the principle of random nucleation and growth（ n = 4）,and the activation energy values at 600-900 and 900-1 350 ℃ are 88. 7 and 295. 5 kJ / mol,respectively.

新疆巴楚小海子岩体铁钛成矿特征及资源利用前景

新疆巴楚小海子是近年来在塔里木大火成岩省探获的一个低品位-大吨位岩浆型钒钛磁铁矿床,其成岩成矿机制以及资源利用前景尚不清楚。文章针对小海子岩体2种含矿岩相橄榄辉长岩和橄榄辉石岩开展了地质地球化学研究。橄榄辉长岩相和橄榄辉石岩相虽然在空间上关系不明,但岩相学观察表明它们矿物组成的差异与矿物堆晶作用有关,且二者具有相似的稀土元素球粒陨石标准化和微量元素原始地幔标准化配分曲线,说明是同源岩浆演化的产物,橄榄石较低的Fo值(67.9~72.5)指示幔源母岩浆在深部岩浆房中发生了分异。小海子岩体和与相距约45 km的瓦吉里塔格相比,岩石组成和地球化学组成相似,表明为同源岩浆成因,但后者矿物组成变化范围更大,指示瓦吉里塔格岩体在形成过程中经历了更高程度的分离结晶作用,这可能是造成瓦吉里塔格岩体比小海子岩体的w(TiO_(2))更高的原因。小海子岩体虽然w(TiO_(2))较低(3%~4%),但铁钛氧化物固溶体分离结构不发育,且矿物颗粒粗大,使得铁和钛选矿解离比中国其他地区的钒钛磁铁矿更为容易,因此钛资源利用前景巨大,笔者建议出台地方性的勘查技术规范,为这类铁钛资源的开发利用提供技术标准。

常温常压下盐酸浸出分离钒钛磁铁精矿中有价金属的试验研究

攀西钒钛磁铁矿组成及矿物结构复杂,难以低成本、高效综合利用其中的有价元素。针对此问题,本文采用常温常压盐酸浸出的方法对该矿物进行了试验探索,考察了盐酸初始质量浓度、浸出液固比、浸出时间、浸出搅拌转速率等主要因素对Fe、TiO_(2)和V_(2)O_(5)浸出率的影响,并通过矿物结构分析了钒钛磁铁精矿中铁、钒、钛分离的机理,得到以下主要结论。盐酸常温常压浸出的较佳工艺条件为盐酸初始浓度20.5%、浸出液固比12:1、浸出时间3.5 h、浸出搅拌转速率600 r/min,该条件下Fe、V_(2)O_(5)和TiO_(2)浸出率分别为84.15%、80.80%、10.05%,浸渣中Fe、V_(2)O_(5)和TiO_(2)品位分别为26.78%、0.378%和32.58%,实现了钛资源的初步富集;盐酸优先溶解试样中钛磁铁矿矿物的主晶矿物磁铁矿,铁、钒优先进入浸出液,而客晶矿钛铁矿及独立钛铁矿被破坏程度极小,富集于浸渣中;该浸出方法不需要额外的加热和加压设备,具有成本低、能源消耗和设备投资较低、操作简便、环境友好的优势,但浸出指标有待提高,后续需要进一步探索催化剂对常温常压酸浸工艺的影响。

攀西某钒钛磁铁矿中钛的赋存状态研究

对攀西某钒钛磁铁矿化学组成、矿物种类及含量、含钛矿物能谱微区成分、矿石中TiO_(2)的平衡概算、含钛矿物产出形式、钛铁矿粒度及解离度等进行详细研究,查清了矿石难选的原因,综合分析了钛精矿的技术指标以及影响选钛效果的主要矿物学因素,可为开发利用攀西某矿产资源提供详细的科学依据。

中国钒钛磁铁矿资源概况及综合利用技术进展

钒钛磁铁矿是以铁、钒和钛为主金属的复合型矿产资源,通常伴生有铜、钴、磷、钪等多种有价组分,具有综合回收利用价值。在概述了中国钒钛磁铁矿资源特点的基础上,针对资源逐渐贫细杂化、综合利用水平较低的状况,着重就预选工艺、铁精矿提质降杂工艺、微细粒钛铁矿选别工艺、伴生资源回收利用工艺技术进展进行了总结,最后分析了目前钒钛磁铁矿选矿存在的工艺技术问题,并指出高效、清洁、可持续发展是未来钒钛磁铁矿选矿技术发展的大方向。

烧结熔剂对钒钛磁铁矿液相高温行为的影响

为了改善钒钛磁铁矿的烧结液相行为,采用微型烧结方法研究了不同熔剂对钒钛磁铁矿液相高温行为的影响.结果表明:从钒钛磁铁矿的液相高温行为考虑,白云石适合做低钛型钒钛矿的烧结熔剂,石灰石适合做低钛型或中钛型钒钛矿的烧结熔剂;与高钛型钒钛矿相匹配的熔剂为高活性的生石灰,菱镁石并不适合做钒钛矿的烧结熔剂.因此,优化钒钛磁铁矿的液相高温行为应根据矿石中的钛含量,调节烧结熔剂中石灰石和高活性生石灰的配比,以及不同性能石灰石和高活性生石灰的使用量.

攀西钛资源综合利用技术应用现状及发展方向

我国四川省攀西地区钒钛磁铁矿资源中钛资源储量巨大,主要以钛精矿形式回收利用,并主要用于硫酸法钛白和酸溶性钛渣生产原料,其产量占全国钛原料市场的75%以上。硫酸法钛白工艺技术成熟,已形成相对完整的“内循环”,但尚未全面突破硫酸法钛白联产技术;电炉冶炼酸溶性钛渣工艺技术较成熟,主流工艺是钛精矿不预处理-实心圆形电极-密闭圆形电炉连续冶炼工艺,钛精矿酸性氧化球团-电炉冶炼一步法工艺、大功率矩圆形电炉冶炼酸溶性钛渣等钛渣新工艺发展较快、发展空间大,是今后主要发展方向。目前攀西地区发展钛产业的一个主要问题是缺乏沸腾氯化法钛白工艺需求的高品位钛资源,未来需要突破攀西高钙镁钛精矿除杂提质制取高品位高钛渣关键核心技术,并同时研发攻关硫酸法钛白附产绿矾和钛石膏回收循环利用技术、高炉钛渣提钛及综合利用技术、钒钛铁精矿非高炉炼铁新技术,以及以钛精矿、钛渣或钛白粉为原料制备含钛及钛基新材料技术,以期获得攀西钛产业的健康可持续发展。