Selective leaching of vanadium from V-Ti magnetite concentrates by pellet calcification roasting-H_(2)SO_(4) leaching process

A novel method of pellet calcification roasting-H_(2)SO_(4) leaching was proposed to efficiently separate and extract vanadium(V)from vanadium-titanium(V-Ti)magnetite concentrates.The leaching rate of V is as high as 88.98%,while the leaching rate of impurity iron is only 1.79%.Moreover,the leached pellets can be used as raw materials for blast furnace ironmaking after secondary roasting.X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy with energy dispersive X-ray spectrometry(SEMEDS)analyses showed that V^(3+)was oxidized to V^(5+)after roasting at 1200℃,and V^(5+)was then leached by H_(2)SO_(4).X-ray diffraction(XRD)analyses and single factor experiment revealed a minimal amount of dissolved Fe_(2)O_(3) during H_(2)SO_(4) leaching.Therefore,a high separation degree of V and iron(Fe)from V-Ti magnetite concentrate was achieved through H_(2)SO_(4) leaching.Compared with the traditional roastingleaching process,this process can achieve a high selectivity of V and Fe,and has excellent prospects for industrial production.

Efficient metallization of magnetite concentrate by reduction with agave bagasse as a source of reducing agents

The reduction behavior and metallization degree of magnetite concentrate with agave bagasse were investigated in an inert atmosphere.The effects of temperature,biomass content,and residence time on reduction experiments and metallization degree were investigated by X-ray diffraction and scanning electron microscopy.Compared with other types of biomass,agave bagasse had lower contents of nitrogen,sulfur,and ash.X-ray diffraction analysis showed that the metallization degree improved with increasing temperature and biomass content.Complete metallization was achieved at 1100℃ for 30 min with 65:35 and 50:50 ratios of the magnetite concentrate to the agave bagasse.These results demonstrate that agave bagasse promotes the efficient metallization of magnetite concentrate without the external addition of a reducing agent.Therefore,this biomass is a technical suitable alternative to replace fossil fuels in steelmaking.

Spatial Variations in Particle Size and Magnetite Concentration on Cedar Beach:Implications for Grain-Sorting Processes,Western Lake Erie,Canada

This study examined spatial variations in the concentration,grain size and heavy mineral assemblages on Cedar Beach（Lake Erie,Canada）.Magnetic studies of heavy mineral-enriched,dark-reddish sands present on the beach showed that magnetite（～150μm） is the dominant magnetic mineral.Surficial magnetic susceptibility values defined three zones：a lakeward region close to the water line（Zone 1）,the upper swash zone（Zone 2） and the region landwards of the upper swash zone （Zone 3）.Zone 2 showed the highest bulk and mass susceptibility（κ,χ） and the highest mass percentage of smaller grain-size（250μm） fractions in the bulk sand sample.Susceptibility（i.e.κandχ） values decreased and grain size coarsened from Zone 2 lakewards（into Zone 1） and landwards （into Zone 3）,and correlated with the distribution of the heavy mineral assemblage,most probably reflecting preferential separation of large,less dense particles by waves and currents both along and across the beach.The eroded western section of Cedar Beach showed much higher concentrations of heavy minerals including magnetite,and finer sand grain sizes than the accreting eastern section, suggesting that magnetic techniques could be used as a rapid,cost-effective way of examining erosion along sensitive coastline areas.

Mineralogical properties and co-sintering characteristics of fluxed iron ore with magnetite concentrates

To investigate the feasibility of co-sintering of fluxed iron ore with magnetite concentrates, the mineralogical properties of a novel fluxed iron ore were studied using particle size analysis, microscopic morphology characterization, and X-ray diffraction Rietveld analysis. Following that, the experiments for granulation performance and basic sintering characteristics were designed under seven different fluxed iron ore ratios, and the integrated ranking of different fluxed iron ore ratios was determined using gray relation analysis. Finally, the results of the industrial trails were combined with the feasibility analysis. Test and experimental results show that the fraction of the fluxed iron ore particles larger than 0.5 mm can account for more than 48%, and the particles have two morphologies: spherical-rough and flaky-smooth. Ca elements are found in the form of calcite (CaCO3) and dolomite (CaMg(CO3)2). The average particle size of granules and powder removal rate can be improved from 2.50 to 3.16 mm and 39.60% to 24.20%, respectively, with the increase in the fluxed iron ore ratio. Furthermore, the fluxed iron ore can improve assimilability and liquid fluidity of magnetite concentrates. In terms of overall granulation performance and sintering characteristics, the fluxed iron ore ratios are graded from best to worst as follows: 12%, 15%, 9%, 18%, 21%, 6% and 3%. The industrial trails show that when the fluxed iron ore ratio is increased, the beneficial effect of the superior sintering characteristics of the fluxed iron ore itself is ideally balanced with the negative effect of the lower amount of additional CaO at 12% ratio, and thus, it is feasible to bring the fluxed iron ore into production at a level of roughly 12%.

Some basic properties of granules from ore blends consisting of ultrafine magnetite and hematite ores

Some basic properties of granules,including the granule size distribution,packed-bed permeability,and chemical composition of the adhering layer,were investigated in this study for four iron ore blends consisting of 5wt%,25wt%,and 45wt%ultrafine magnetite and 25wt%ultrafine hematite concentrates.The effects of varying the sinter basicity(CaO/SiO2 mass ratio=1.4 to 2.2)and adding ultrafine concentrates on the variation of the adhering-layer composition and granule microstructure were studied.Moreover,the effect of adhering-layer compositional changes on sintering reactions was discussed in combination with pot sintering results of ore blends.Increasing sinter basicity led to an increase in the basicities of both the adhering layer and the fine part of the sinter mix,which were higher than the overall sinter basicity.When the sinter chemistry was fixed and fine Si-bearing materials(e.g.,quartz sand)were used,increasing the amount of ultrafine ores in the ore blends tended to reduce the adhering-layer basicity and increase the SiO2 content in both the adhering layer and the fine part of the sinter mix,which will induce the formation of low-strength bonding phases and the deterioration of sinter strength.The adhering-layer composition in granules can be estimated in advance from the compositions of the-1 mm fractions of the raw materials.

A Study of Rock Magnetism of High-Grade Hematite Ores

Rock magnetism is useful in various applications. Hematite is one of the two most important carriers of magnetism in the natural world and its magnetic features were mostly studied through laboratory experiments using synthetic hematite samples. A gap exists between the magnetic behaviors of hematite contained in the natural rocks and ores and those of synthetic hematite samples. This paper presents the results of a rock magnetism study on the natural hematite ores from the Whaleback mine in the Hamersley Province in the northwest of Western Australia. It was found that high-grade hematite ores carry a much higher remanent magnetization than induced magnetization. Hematite ores with less than 0.1% magnetite appear to have an exponential correlation between the bulk susceptibility and hematite content in weight percentage, different from the commonly accepted linear relationship between the bulk susceptibility and hematite content obtained from synthetic hematite samples. The new knowledge gained from this study contributes to a better understanding of magnetic behaviors of hematite, particularly natural hematite, and hence applications to other relevant disciplines.

Mineralization characteristics of pellets prepared by ultrafine magnetite concentrate:influence on metallurgical property and improving method

The reducing property of pellets prepared by ultrafine magnetite concentrate(UMC)and improving method were revealed.The results show that the reduction degree of UMC pellets is only about 56%compared with that of pellets prepared from ordinary iron ore concentrate with relatively coarse particle size,which is significantly lower than the general reduction degree of about 70%.When the composite binder composed of bentonite and organic binder was added,the reduction degree was significantly increased to 69.66%.The revealed mechanism shows that the reduced pellets with common bentonite have a concentric structure,the oxidation gap between the inner and outer layers is obvious,and the outer dense oxide layer hinders the oxidation and reduction of the inner layer.After adding the composite binder,the organic components significantly improved the internal porosity of the pellets and the aggregation degree of ultrafine iron ore concentrate particles in the granulation process,forming a porous structure.The non-uniform double-layer structure is eliminated,and the increased pores are conducive to the internal diffusion of CO,and finally the reduction degree of pellets is increased to the level equivalent to that of ordinary magnetite pellets.

Influence of basicity on metallurgical performances of fired super high-grade magnetite pellets in hydrogen-rich gases

The influence of basicity on the metallurgical performances and reduction characteristics of fired super high-grade magnetite pellets under the simulated shaft furnace gas conditions was investigated.The fired pellets in the basicity range of 0.09(natural basicity)to 1.00 show superior reducibility and low-temperature disintegration performance.However,in the basicity range of 0.20–0.80,the abnormal swelling of the fired pellets occurs.Improving basicity from 0.09 to 0.40 promotes the generation of low melting point slag phases and lower porosity of fired pellets,and accelerates the growth and densification of hematite crystals,impeding the reduction of hematite particles and the formation of metallic iron shell.In addition,the slags that distribute between the hematite particles absorb the reduction stresses by increased distances between the particles during the reduction process,which leads to the large reduction swelling of pellets.

Improving roasting performance and consolidation of pellets made of ultrafine and super high grade magnetite concentrates by modifying basicity

For improving the strength of pellets made of ultrafine and super-high-grade magnetite concentrates,the influence of basicity(CaO/SiO2 ratio)on the roasting and consolidation of pellets was investigated.The results showed that with the basicity of pellets increasing from 0.09 to 0.60,the compressive strength of both preheated and roasted pellets achieved an evident improvement from 502 and 2519 to 549 and 3096 N/pellet,respectively;meanwhile,the roasting time decreased from 15 to 9.min.The low-viscosity liquid phases were easily generated in fired pellets at the basicity range of 0.40-0.60 under the roasting temperature of 1240℃,filled the voids between hematite particles and tightened the bonding among particles,effectively restraining the generation of concentric cracks and decreasing the porosity of fired pellets;low-viscosity liquid phases facilitated the solid diffusion of hematite,leading to the formation of coarse hematite crystals and thicker connecting necks.

河北某普通磁铁矿制备超纯铁精矿试验研究

河北某普通磁铁矿TFe品位为65.25%,矿石性质结构简单,具有制备超纯铁精矿的潜力。研究采用多元素及X射线衍射图、物相分析等方法对原矿进行了工艺矿物学研究,并在此基础上对其进行了提纯试验。结果表明,原矿经过弱磁选粗选后,在磨矿细度-0.038 mm占85%的条件下经弱磁选再选、磁选柱精选得到TFe品位为71.31%的磁选柱精矿以及TFe品位68.12%、产率为3.32%的磁选柱铁尾矿。通过进一步考察药剂制度和工艺流程对铁矿精矿品位、回收率等选别指标的影响,确定了合适的药剂制度。而后磁选柱精矿经1粗3精反浮选降硅工艺试验流程,最终可获得含TFe品位71.95%、综合回收率为80.50%的超纯铁精矿,浮选尾矿TFe品位68.17%符合普通铁精矿标准。通过对选别产品进行试样化学成分分析及残余药剂测定,进一步证明该工艺流程可以实现超纯铁精矿的制备。该工艺在抛尾率为10.79%条件下,将原矿样的73.04%转化为超纯铁精矿,对这一地区超纯铁精矿的制备具有重要的指导意义,也为国内其他地区磁铁矿制备超纯铁精矿的研究提供了一定的参考价值。

磁铁矿矿浆的矿石质量流量检测新技术

针对选矿过程中强磁性磁铁矿矿浆所包含矿石质量流量难以检测的问题,在分析现有主要检测技术的基础上,结合应用现场流程的特点,创新性提出一种单流量-双浓度的矿浆质量流量检测法,通过检测流程加水的流量以及加水前后矿浆浓度的变化,实现对强磁性磁铁矿矿浆所包含矿石质量流量进行精确检测。实际应用表明:该方法具有检测精度高、适应性强、稳定性好等特点,特别适用于含有磁铁矿的矿浆。

安徽某超级铁精矿工艺矿物学研究

为了查明某超级铁精矿中SiO_(2)含量偏高的原因及其主要矿物嵌布特征,通过化学分析、荧光光谱(XRF)、扫面电子显微镜(SEM)、X射线电子探针分析及光学显微镜等多种测试分析手段,对有代表性的超级铁精矿产品进行了工艺矿物学研究。研究结果表明:超级铁精矿中SiO_(2)含量0.338%,石英为元素硅的主要载体,矿物含量为0.21%;元素铁主要以磁性铁形式存在,磁铁矿含量99.28%;盐酸不溶物主要为石英、铁闪石、钙铁辉石、铁铝榴石,这4种矿物大多与磁铁矿紧密共生,以连生体形式进入精矿,从而导致超级铁精矿中的SiO_(2)含量偏高。

鞍山地区微细粒贫磁铁矿石磁选工艺研究

鞍山地区许东沟和哑巴岭采区的铁矿石铁品位为29.50%,铁矿物主要为磁铁矿,主要脉石为石英。为高效开发利用该矿石,在采用X荧光分析、化学成分分析、铁物相检测和扫描电子显微镜分析矿石性质基础上,进行了湿式粗粒中磁预选—阶段磨矿、阶段弱磁选—淘洗机精选条件试验和扩大连选试验。结果表明:①-2.5 mm高压辊磨产品经过筒式磁选机中磁预选,粗精矿铁品位为40.20%、铁回收率为89.76%;②预选粗精矿经过两阶段磨矿(一、二段磨矿细度分别为-0.074 mm占75%和-0.045 mm占90%)、三阶段弱磁选和一段淘洗机精选,最终获得产率35.73%、铁品位67.08%、铁回收率81.24%的铁精矿,尾矿铁品位为8.61%,研究结果可作为该矿石开发利用依据。

攀西某钒钛磁铁矿重选尾矿再回收试验

攀西某超低品位钒钛磁铁矿为了回收利用总尾矿中的钛资源,在尾矿性质研究的基础上,进行了重选尾矿再回收试验。试验结果表明:尾矿通过强磁选—分级—弱磁选工艺,可得到全铁品位为19.07%、TiO_(2)品位为18.25%的入浮矿样;对入浮矿样开展脱硫—1粗3精开路浮选,可得到TiO_(2)品位47.27%、TiO_(2)回收率70.78%的合格钛精矿,同时分级后的粗粒级矿物通过重选工艺,在摇床床面精矿与尾矿的截取比例为2∶8的条件下,可获得精矿产率为6.46%、全铁品位为13.41%、TiO2品位为8.83%的钛原料,能够并入主系统对其中的钛金属进行再次选别回收,以获得更高的钛资源综合利用率。

Oxidation and Induration Characteristics of Pellets Made from Western Australian Ultrafine Magnetite Concentrates and Its Utilization Strategy

Western Australian magnetite concentrates normally have ultrafine granularity and much higher specific surface areas than Chinese magnetite concentrates owing to the significant pre-grinding and beneficiation for saleable iron grade. Such characteristics will inevitably affect the subsequent pelletization process. However, very few investi- gations have been done before. Thus, the oxidation and induration characteristics of pellet made from a Western Aus- tralian ultrafine magnetite concentrate were revealed by conducting routine preheating-roasting tests in an electric tube furnace and investigating the microstructure of fired pellets under an optical microscope in comparison with that of pellets made from typical Chinese magnetite concentrate. The liquidus regions of CaO-SiO2-Fe2O3 and CaO-SiO2- Al2O3 ternary systems in air at various temperatures were calculated by FactSage software to explain the importance of liquid phase in the consolidation of fired pellets. The results show that pellet made from ultrafine magnetite con- centrate possesses better oxidability and preheating performance than that made from Chinese magnetite concentrate. However, it has inferior roasting performance, usually requiring conditions of roasting at 1280℃ for at least 30 rain to acquire sufficiently high compressive strength, which are attributed to higher temperature sensitivity caused by its smaller particle size and less formation of liquid phase because of low impurities like CaO and Al2O3 in raw materials. Correspondingly, its roasting performanee can be significantly improved by blending with Chinese magnetite concen- trates or increasing the pellet basicity （WCaO/WSiO2）. By comprehensive evaluation, blending with Chinese iron ore concentrates is an appropriate way to utilize Western Australia ultrafine magnetite concentrates.

Mechanism of Strength Improvement of Magnetite Pellet by Adding Boron-bearing Iron Concentrate

The mechanism of improving compressive strength of magnetite pellet by adding boron-bearing iron concentrate was studied. Boron-bearing iron concentrate and magnetite were mixed, pelletized and roasted under differ ent roasting conditions. Then, compressive strength of pellets was tested, and polished sections of the roasted pellets were analyzed from the perspective of mineralogy. Finally, the effects of different proportions, roasting temperatures and roasting time of boron-bearing iron concentrate on the compressive strength of magnetite pellets were investigated and explained.

配加钒钛磁铁精矿烧结杯试验及烧结矿冶金性能试验

为充分利用哈密地区钒钛精矿,进行了配加钒钛精矿烧结杯试验及烧结矿冶金性能试验。试验结果表明:随着钒钛磁铁精矿配比的增加,烧结利用系数、成品率均呈逐渐上升的趋势,烧结矿转鼓指数呈逐渐下降的趋势;配加钒钛磁铁精矿后,烧结矿低温还原粉化率RDI_(+3.15mm)呈逐渐降低的趋势,烧结矿900℃还原度总体上呈逐渐降低的趋势;烧结矿软化熔滴性能明显变好。

河南某铁铜矿石优先浮铜尾矿弱磁选铁试验

河南某铁铜矿石结构构造及矿物组成均较简单,有用矿物磁铁矿和黄铜矿的粒度均较粗。为了确定2粗3精2扫闭路优先浮铜尾矿弱磁选选铁的合理工艺流程,开展了直接1粗1精弱磁选、弱磁粗选精矿磨矿后弱磁精选、先磨矿后1粗1精弱磁选3种工艺选铁试验。结果表明,弱磁粗选精矿磨矿后弱磁精选工艺效果最佳,在再磨细度为-0.074 mm 90%、弱磁粗选和弱磁精选磁场强度分别为95.54 kA/m和67.58 kA/m情况下,可获得铁品位65.50%、回收率53.53%的铁精矿。

袁家村铁矿闪石型磁铁矿高压辊磨及阶磨阶选工艺技术研究

对太钢袁家村铁矿闪石型磁铁矿进行了高压辊磨-预选及阶磨阶选工艺技术研究。为了降低入磨矿石选比,采用高压辊磨进行超细碎并对-3 mm粒级物料进行湿式预选,可以抛出产率22%的粗粒尾矿,预选精矿TFe品位提高到36%左右。高压辊磨前后矿样的磨矿功指数分别为11.91 kW·h/t和11.11 kW·h/t。高压辊磨-预选-阶磨阶选流程试验获得了精矿产率33.92%、TFe品位67.13%、回收率75.75%的指标,选比由2.95下降至2.27。高压辊磨-预选-阶磨阶选工艺为此类低品位磁铁矿大规模低成本开采提供了节能降耗新思路。

强化高配比磁铁精粉制粒工艺研究

研究针对某内陆型钢企烧结现场原料条件,以当地两种磁铁精粉A和B为主要原料,在实验室圆筒制粒机中研究了高配比磁铁精粉的制粒行为,并考察了原料预润湿、制粒水分、生石灰用量、粗矿粉和返矿比例等因素对制粒效果的影响。结果表明:在混匀矿中磁铁精粉配比高达90%及模拟现场制粒条件的情况下,制粒后混合料中+3mm含量仅为13.81%,透气性指数为14.1JPU。对原料进行预润湿能显著改善混合料的制粒性能,透气性指数提高至41.7 JPU;另外,提高制粒水分、延长制粒时间、提高生石灰用量及粗矿粉和返矿比例均有利于改善高配比磁铁精粉的制粒效率。