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.

Three-liquid-phase extraction and separation of V(V) and Cr(VI) from acidic leach solutions of high-chromium vanadium–titanium magnetite

A new method by liquid-liquid-liquid three phase system, consisting of acidified primary amine N1923 （abbreviated as A-N1923）, poly（ethylene glycol） （PEG） and （NH4）2S04 aqueous solution, was suggested for the separation and simultaneous extraction of Ⅴ（Ⅴ） and Cr（Ⅵ） from the acidic leach solutions of high- chromium vanadium-titanium magnetite. Experimental results indicated that Ⅴ（Ⅴ） and Cr（Ⅵ） could be selectively enriched into the A-N1923 organic top phase and PEG-rich middle phase, respectively, while AI（Ⅲ） and other co-existing impurity ions, such as Si（Ⅳ）, Fe（Ⅲ）, Ti（Ⅳ）, Mg（Ⅱ） and Ca（Ⅱ） in acidic leach solutions, could be enriched in the （NH4）2SO4 bottom aqueous phase. During the process for extraction and separation of Ⅴ（Ⅴ） and Cr（Ⅵ）, almost all of impurity ions could be removed. The separation factors between Ⅴ （Ⅴ） and Cr（Ⅵ） could reach 630 and 908, respectively in the organic top phase and PEG middle phase, and yields of recovered Ⅴ（Ⅴ） and Cr（Ⅵ） in the top phase and middle phase respectively were all above 90%. Various effects including aqueous pH, A-N1923 concentration, PEG added amount and （NH4）2SO4 concentration on three-phase partitioning of Ⅴ（Ⅴ） and Cr（Ⅵ） were discussed. It was found that the partition of Cr（Ⅵ） into the PEG-rich middle phase was driven by hydrophobic interaction, while extraction of Ⅴ（Ⅴ） by A-N1923 resulted of anion exchange between NO; and H2V10O4-28. Stripping of Ⅴ（Ⅴ） and Cr（Ⅵ） from the top organic phase and the middle PEG-rich phase were achieved by mixing respectively with NANO3 aqueous solutions and NaOH-（NH4）2SO4 solutions. The present work highlights a new approach for the extraction and purification of V and Cr from the complex multi-metal co-existing acidic leach solutions of high-chromium vanadium-titanium magnetite.

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%.

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.

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.

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。

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。

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.

球团配加钒钛磁铁精矿试验研究

为充分利用哈密地区钒钛磁铁精矿,进行了配加钒钛磁铁精矿球团试验及球团矿冶金性能试验。试验结果表明:钒钛精矿球团生球爆裂温度均大于600℃,可满足竖炉生产要求;与普通精矿相比,钒钛磁铁精矿需要更高的焙烧温度,本次试验将焙烧温度提高了50℃左右,但球团矿抗压强度仍略偏低;成品球团矿还原膨胀率在8.19%~12.09%;成品球团矿900℃还原度在54.50%~63.20%。

钒钛铁尾矿制备绿色建筑材料的研究进展

钒钛磁铁矿是以铁、钒、钛为主的多金属元素共生的复合矿,在世界分布不均衡。中国是该矿石的主要产出国之一,该矿石分布在五个主要矿带。钒钛铁尾矿是钒钛磁铁矿选矿过程中产生的固体工业废弃物,是一种多金属伴生的铁尾矿。该尾矿在中国的堆存量巨大,富含很多有用化学组分,也被称为人工矿床。该尾矿以硅酸盐为主,主要化学成分是二氧化硅、三氧化二铝、氧化钙和氧化铁等,主要矿物是脉石矿物。国内外学者对其在绿色建筑材料综合利用方面做了很多有益探索,但总体来看,这些研究更多停留在实验室里。主要原因是(1)不同尾矿库甚至同一尾矿库的钒钛铁尾矿理化性能可能有较大差异,尾矿原料的稳定性不足;(2)受尾矿原料不稳定的理化性能影响,中试结果经常出现较大差异,难以实现规模化利用;(3)钒钛铁尾矿库大多地处偏僻,运输成本高,且缺乏高附加值的尾矿产品,规模以上企业因投入大产出小望而生畏。本文综述了钒钛铁尾矿在中国的地域分布和堆存量,重点研究了其化学组成、矿物组成、粒度分布和重金属浸出,分析了其作为主要原料在绿色建筑材料方面的研究进展,指出了存在问题并展望了发展前景。

基于钒钛磁铁矿尾矿的发泡陶瓷制备及性能研究

攀西地区铁尾矿的大量堆积严重污染了当地的生态环境。固废基发泡陶瓷吸波材料在解决铁尾矿堆积问题的基础上,推进了发泡陶瓷在吸波材料领域的应用。通过正交试验探索了烧结温度、保温时间和发泡剂掺量对发泡陶瓷物理性能的影响,并综合分析得出优选烧结方案:烧结温度为1190℃,保温时间为60 min,发泡剂掺量为质量分数0.3%。依照此方案制备的发泡陶瓷体积密度为0.23 g/cm^(3),体积吸水率为0.76%,抗压强度为0.73 MPa,导热系数为0.06 W/(m·K),孔隙率为89.89%。在正交试验制定的工艺基础上,探索了试样厚度对发泡陶瓷吸波性能的影响。研究结果表明:在烧结温度1170℃,吸波剂掺量为质量分数30%时,厚度为15 mm的发泡陶瓷吸波性能最优,在0.5~18 GHz的频率范围内反射损耗降低至-28.58 dB,显示出2.35 GHz的有效吸收带宽。该研究为钒钛磁铁矿尾矿的资源化利用和发泡陶瓷在吸波材料方面的运用提供了参考。

氧气体积分数对钒钛磁铁矿球团氧化过程的影响

提高高炉球团配比有利于降低钢铁行业的污染物和碳排放,为了使钒钛磁铁矿球团在高炉中得到更好的应用,本文研究了氧气体积分数对钒钛球团氧化速率的影响,利用动力学模型分析了其氧化反应的控速环节,分析了钒钛球团氧化过程物相组成、矿相结构等演变规律。结果表明:富氧能促进钒钛磁铁矿球团的氧化,钒钛磁铁矿球团的氧化过程符合未反应核模型,氧化过程前期以界面化学反应控速为主,后期以内扩散控速为主,内扩散阻力大于界面化学反应时的氧化度随着氧气体积分数的增加而降低。钒钛磁铁矿球团的氧化伴随着Fe_(3)O_(4)→Fe_(2)O_(3)、Fe_(2.75)Ti_(0.25)O_(4)→Fe_(2)TiO_(4)/FeTiO_(3)→Fe_(9)TiO_(15)的物相转变过程,在预热氧化过程会出现赤铁矿连晶,致使矿物间的孔隙率降低,氧气内扩散的阻力增大,氧化反应的速率降低。

钒钛磁铁矿尾矿/高岭土复合整体材料的制备及光催化降解罗丹明B的研究

在钒钛磁铁矿的开发利用过程中形成了大量堆积的尾矿,既造成土壤污染,还危害周边居民的身体健康。因此,开发钒钛磁铁矿尾矿的有效利用方法具有重要意义。本实验使用钒钛磁铁矿尾矿和高岭土为基体、硅溶胶为粘接剂、氯化铵为改性剂,制备了钒钛磁铁矿尾矿/高岭土复合整体材料,考察了制备条件对材料光催化降解罗丹明B的影响,使用XRF、XRD、SEM、BET、XPS和UV-Vis DRS对制备的材料进行了表征。结果表明,制备的复合光催化材料在60 min内对罗丹明B的去除率达到了71.5%,4次重复使用后,对罗丹明B的光催化降解仍具有一定效果。研究对钒钛磁铁矿尾矿的整体利用及“以废治废”综合利用有一定意义。

铝土矿尾矿协同钒钛磁铁矿尾矿制备刚玉质复相陶瓷

以铝土矿尾矿和钒钛磁铁矿尾矿为原料,经混料、成型和高温烧成等工艺制备了刚玉质复相陶瓷,研究了钒钛磁铁矿尾矿添加量、烧成温度等因素对制得复相陶瓷材料的物相、显微形貌及力学性能的影响规律。结果表明:当铝土矿尾矿与钒钛磁铁矿尾矿质量比为9∶1时,在1100℃下保温3 h制得刚玉质复相陶瓷材料的性能最优,其体积密度为2.71 g/cm^(3),抗压强度为276.9 MPa,抗折强度为67.3 MPa。

攀西太和钒钛磁铁矿中钴的分布规律及赋存状态

这是一篇工艺矿物学领域的论文。钴是重要的战略金属,主要以共-伴生元素的形式分布于金属矿床中。攀西地区的钒钛磁铁矿矿床是我国最大的钒钛铁资源基地,其矿床中伴生了大量的钴资源,但富钴矿石中钴在矿物相之间的分布规律及微观的赋存状态还未被查明。本文选择攀西地区太和钒钛磁铁矿矿床作为研究对象,利用化学分析、光学显微镜、扫描电镜(SEM-BSE)、X射线衍射分析(XRD)、高级矿物鉴定和表征系统(AMICS)、电子探针(EPMA)等分析技术对矿床中典型的富钴矿石进行了化学成分、矿物组成以及Co元素在不同矿物间分布规律及赋存状态进行了研究,研究结果表明富钴样品矿物中硫化物具有较高的钴含量,而铁钛氧化物中钴含量较低,其他矿物中几乎不含有钴,钴的分布规律表明其主要分布于硫化物中,少量分布于铁钛氧化物以及脉石矿物中。样品中钴元素具有独立矿物-硫钴镍矿和类质同象两种赋存状态。研究结果为该地区钴资源的综合利用提供矿物学依据。

钒钛磁铁矿剥离废石特性与综合利用实践

这是一篇矿业工程领域的论文。钒钛磁铁矿铁矿采选过程中产生大量剥离废石,主要分为三类:剥离土物料、剥离岩石物料和表外矿。由于风化、雨淋等作用,废石中的有毒有害元素会对周围环境造成二次污染。废石资源的回收再利用大有裨益,能够提高资源利用率并有效减少土地占用和环境污染。因此,本文对三种剥离废石的特性进行了系统分析,并以此为依据,对其综合利用途径分别进行分析和总结。剥离土物料和剥离岩石物料可以根据其风化程度,作为尾矿坝筑坝材料、建筑砂石用料等,变废为宝;表外矿可以通过预选提高品位,进行回收利用。本文能够为钒钛磁铁矿剥离废石的进一步综合利用提供参考借鉴,从而大幅提高钒钛磁铁矿矿资源综合利用水平。