Modification of ilmenite surface properties by superficial dissolution method

Acid surface dissolution as a pretreatment method converts Fe²⁺ ions on the ilmenite surface to Fe³⁺ ions. XPS analysis showed that the content of Fe³⁺ increases from 48.5% to 59.8% after surface dissolution for 15 min in a solution of sulfuric acid with a concentration of 10%. This conversion, without any phase transformation, decreases the zeta potential of ilmenite in a wide pH range, resulting in a shift in IEP (Iso-Electric Point) from a pH of 5.4 to 2.3. FTIR spectra and zeta potential measurements showed that the increase of oleate ions adsorption on the ilmenite surface, resulting from the surface dissolution process, is insignificant. After surface dissolution, the formation of more ferric iron oleate species (Ksp = 10^−29.7) being more stable than ferrous iron oleate (Ksp = 10^−15.5) compounds yields an increase of ilmenite hydrophobicity and floatability in a wide pH range. Using 3.65 × 10⁻⁴ M sodium oleate at a pH of 6.3, the maximum flotation recoveries are obtained as 73.5% and 92% for non-treated and acid pretreated ilmenite, respectively.     

越南某钛铁砂矿选矿试验

越南某钛铁砂矿粒度为-80目占62.34%,TiO₂品位为6.04%,主要金属矿物为钛铁矿和钛磁铁矿,部分钛铁矿物已单体解离。为高效开发利用该矿石资源,对有代表性的矿石进行了选矿试验研究。结果表明：①矿石采用1粗1精摇床重选、重选中矿1次强磁选均可获得较高品位的钛铁精矿;②矿石经1粗1精摇床重选,重选中矿1次强磁选,重选尾矿和强磁选尾矿合并再磨至-200目占80%后经1粗2精、中矿顺序返回浮选流程处理,最终获得了TiO₂品位为46.45%、回收率为77.52%的钛铁精矿。     

The influence of particle shape properties and associated surface chemistry on the flotation kinetics of chalcopyrite

The role of particle shape properties in determining flotation kinetics was investigated in this study. −150/+75 μm chalcopyrite was floated in a microflotation cell, and shape properties of the timed concentrates were quantified using a mineral liberation analyser - a mineralogical characterisation system based on automated scanning electron microscopy. It was found that, when floated in the absence of collector, particles with angular shape features reported to the concentrate faster than round particles. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) showed that angular particles also exhibited surface chemistry characteristics favourable for flotation. When particle floatabilities were high (i.e. when floated in the presence of potassium amyl xanthate), shape properties were not found to contribute significantly to the rates at which particles floated.     

钛铁矿浮选药剂及微波预处理改善其浮选指标的研究进展

我国钛资源钛品位低、性质复杂,浮选是富集钛铁矿最有效的方法。从捕收剂、活化剂、抑制剂角度综述了钛铁矿浮选药剂的研究进展。综述了钛铁矿表面性质与其可浮性的关系及微波表面预处理提高钛铁矿可浮性的研究进展。钛铁矿浮选时捕收剂主要通过化学吸附方式作用在矿物表面,捕收剂组合使用较单一捕收剂对钛铁矿的浮选指标好;在钛铁矿浮选抑制剂方面,铅离子活化的报道较多,铜离子活化、硫酸活化等也逐渐被报道;微波用于钛铁矿表面预处理,降低了捕收剂、抑制剂、活化剂等浮选药剂的消耗量,具有较好的运用前景。今后,钛铁矿浮选技术发展的主要方向仍然是开发新型、环保、低成本、高效的浮选药剂。     

Flotation behaviors of ilmenite,titanaugite, and forsterite using sodium oleate as the collector

The flotation behaviors of ilmenite, titanaugite, and forsterite using sodium oleate as the collector were investigated using microflotation experiments, zeta-potential measurements, Fourier transform infrared (FT-IR) analyses, X-ray photoelectron spectroscopy (XPS) analyses and the artificially mixed minerals flotation experiments. The results of the microflotation experiments indicate that ilmenite exhibits good floatability when pH > 4.0. Titanaugite possesses a certain floatability at pH 4.0–6.0 and pH > 10.0, and forsterite possesses certain floatability at pH 5.0–7.0 and pH > 9.0. The results of FT-IR and XPS analyses indicate that sodium oleate mainly interacts with Fe, resulting in ilmenite flotation; that the Ca and Mg on the titanaugite surface chemically reacted with sodium oleate, and that the Mg on the forsterite surface chemically reacted with sodium oleate under acidic condition. However, sodium oleate mainly reacted with the Ca and Mg on the titanaugite surface, whereas sodium oleate mainly reacted with the Mg on the ilmenite and forsterite surfaces under alkaline conditions. The results of the artificially mixed minerals flotation experiment demonstrate that the concentrate of TiO₂ grade increases from 16.92% to 30.19% at pH 5.4, which represents the appropriate conditions for the flotation separation of ilmenite from titanaugite and forsterite under weak acidic conditions.     

钛磁铁矿对钛铁矿浮选的影响

钛磁铁矿对钛铁矿的浮选会产生非常不利的影响。单矿物研究结果表明:钛磁铁矿具有比钛铁矿更好的可浮性,浮选中会优先进入精矿,影响精矿品位,并增加药剂消耗;钛磁铁矿易产生磁团聚现象,造成机械夹带,包裹脉石的钛磁铁矿磁团聚体进入浮选精矿中会降低精矿品位和回收率。钒钛磁铁矿选铁尾矿实际矿样的试验结果表明:不除铁直接浮选钛时,精矿TiO2品位为44.02%,回收率为44.38%;而先经弱磁选除去钛磁铁矿后,采用相同的浮选流程和药剂制度,浮选精矿的TiO2品位提高到47.40%,回收率提高到52.64%。     

钛铁矿浮选药剂及其作用机理研究进展

原生钛铁矿石占有率高、品位低、嵌布复杂是我国钛铁矿资源的基本特征,采用传统的磁选工艺,钛铁矿回收率较低。相对于磁选工艺,浮选工艺在细粒物料回收方面具有显著的优越性,是微细粒钛铁矿回收的有效工艺。为了促进钛铁矿浮选工艺技术的进步,系统总结了钛铁矿浮选药剂的研究进展,综述了钛铁矿浮选药剂及其作用机理方面的研究成果。对研究与生产实践中常用的脂肪酸类、膦酸类、胂酸类、羟肟酸类等钛铁矿浮选捕收剂进行了逐一介绍;新型组合捕收剂结合了多种常规捕收剂的优点,是捕收剂开发与应用的重要研究方向;调整剂主要包括钛铁矿的活化剂和脉石矿物的抑制剂,这些药剂在脉石矿物与钛铁矿可浮性相当时,对浮选分离起着决定性的作用。结合现代测试分析方法,分析、综述了浮选药剂在矿物表面的作用方式,为钛铁矿的浮选提供了理论基础,为选矿工作者提供了技术参考。     

攀西钒钛磁铁矿的选矿技术现状及发展趋势

攀西钒钛磁铁矿是我国铁、钒、钛等重要战略资源,经过多年的努力,形成了采、选、冶的铁、钒及钛完整产业链,初步实现了钒钛磁铁矿的综合利用,但存在资源利用水平不高、部分有用资源未提取等技术难题,目前铁、钒和钛三种资源利用率分别为70%、41%和21%,尚未实现钴、镍、铬、钪等宝贵金属的利用。结合攀西钒钛磁铁矿的矿物学特性对该矿的选矿技术现状进行综述,表明钒钛磁铁矿通过"阶段磨矿、阶段选别"选矿方式获得铁精矿和选铁尾矿,选铁尾矿再经过高梯度强磁选—重选—浮选—电选流程获得钛精矿,钒和铬元素以类质同象形式进入铁精矿中;通过不断地优化和开发新型选矿工艺,有利于实现攀西钒钛磁铁矿的绿色高效综合利用。     

The effects of electrical comminution on the mineral liberation and surface chemistry of a porphyry copper ore

The surface chemistry and mineral liberation changes of a porphyry copper ore after high voltage pulse (HVP) electrical comminution have been investigated using X-ray photoelectron spectroscopy (XPS) and mineral liberation analysis (MLA). Previous studies suggest that electrical comminution has the potential to improve downstream flotation recoveries, due to increased mineral liberation. However, until now the effects on the surface chemistry have not been investigated in detail.The mineral liberation results showed that chalcopyrite was more liberated in the electrical comminution product than in mechanical comminution, noticeably in the coarser size fractions. The surface chemistry of pure chalcopyrite was investigated, using XPS, and high resolution scans of iron and sulphur showed that both comminution methods led to iron oxidising preferentially leaving behind a passivating film of copper sulphides. However, the HVP product oxidisation was more severe with more iron oxide being produced and further oxidation of the remaining copper sulphides into copper sulphate. An attrition grinding stage may be useful in removing the oxidised layer from the surface of the particles prior to flotation separation. This paper presents a new application of the HVP technology in hybrid procedures using electrical comminution and mechanical grinding to prepare the flotation feed, rather than using excessive pulse energy to fully disintegrate ore to the flotation size. Better liberation and flotation performance were achieved through the hybrid procedures than the comparative mechanical comminution.     

化学在矿物浮选中的应用及进展

简要介绍了溶液化学、电化学、胶体化学和晶体化学在矿物浮选中的研究概况、应用及进展。     

Pyrochlore surface oxidation in relation to matrix Fe composition: A study by X-ray photoelectron spectroscopy

The flotation recovery of pyrochlore from the Saint-Honore Carbonatite ore has been related to the variability in the mineral matrix Fe content; high Fe pyrochlore grains consistently report to the tails. Previous research has tentatively suggested that surface oxidation of high Fe pyrochlore grains may be driving partitioning of the pyrochlore grains to the tails. X-ray photoelectron spectroscopy (XPS) was used to examine the relationship between matrix Fe content and surface oxidation in high Fe pyrochlore grains and high Fe zoned regions in pyrochlore grains from the Carbonatite ore. XPS analyses of pyrochlore grains showed that a greater proportion of surface oxidation species corresponded to the zones with high matrix Fe content. The XPS data along with previously presented Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) data demonstrates a relationship between matrix Fe content and collector attachment. The Fe rich pyrochlore grains or zones show a higher degree of oxidation relative to the Fe poor grains or zones. The data reveal that collector attachment favors low Fe grains or zones, likely in response to a lower degree of surface oxidation.     

磨矿介质对闪锌矿浮选行为的影响研究

在湿式磨矿条件下分别以钢球和陶瓷球作为磨矿介质,以丁基黄药为捕收剂,研究闪锌矿在不同磨矿体系下的可浮性差异。结果表明,在相同药剂条件下,相比钢球介质湿磨环境,以陶瓷介质湿磨后闪锌矿可浮性较高;不同磨矿介质对闪锌矿的最佳浮选pH值几乎没有影响,最佳浮选pH值均保持在4~6之间;硫酸锌对闪锌矿的抑制作用受磨矿介质影响较小。借助扫描电镜和X射线光电子能谱检测考察磨矿介质对闪锌矿浮选行为的影响机理,陶瓷介质湿磨后闪锌矿表面较为平整,表面覆盖的金属氧化物较少;钢球介质湿磨后闪锌矿表面腐蚀较为严重,表面覆盖有大量白色絮状氧化物,降低了闪锌矿的可浮性;在钢球介质湿磨体系中,由于钢球介质的磨损脱落导致矿浆中存在大量的Fe³⁺;随着磨矿时间的延长,Fe³⁺及Zn²⁺不断与矿浆中OH^-结合生成金属氧化物覆盖在矿物表面,导致矿浆中金属离子含量不断下降。     

Evolution of flotation chemistry and chemicals: A century of innovations and the lingering challenges

The history of mineral flotation is a record of over a century of impressive innovations, especially in the development of flotation chemistry and chemicals, the principles of their action, their manufacture and the role they play in sustaining efficiencies and productivities even as the quality and grade of ores decline, and the severity of the challenges increases. We emphasize the major innovations that have directed progress on this subject, especially those innovations that have positively impacted industrial scale applications. An analysis is given that organizes the evolution of flotation chemistry and reagents into four historical and one emerging period. As in many other technology areas, flotation chemistry research and development have reached a plateau in the face of mounting industry challenges related to water and energy consumption, decline in the ore quality, economic uncertainty, and health, safety and environmental (HSE) aspects. Elevating us off this plateau will require several necessary steps, including more detailed, holistic understanding of practical systems, better integration of chemical effects into flotation models, a more robust education system to produce adequate numbers of qualified engineers, development of novel technologies and chemical schemes that address the challenges identified above, and a stronger commitment by mining companies to actually adopt those innovations. Success in developing novel technologies will be greatly improved when we can confront the chemical complexity in flotation systems. This in itself is one of the grand challenges in the emerging period. We outline some directions to achieve this goal. The mineral processing industry must take the initiative towards these goals in order to bring about the necessary transformation if we are to maintain a sustainable technology.     

Impact of gypsum supersaturated solution on surface properties of silica and sphalerite minerals

In some sulphide mineral flotation operations, the process water contains high concentrations of calcium and sulphate ions that exceed the solubility limit of gypsum. It has been speculated that the gypsum supersaturated process water would lead to precipitation of gypsum which could coat on mineral surfaces by either nucleation or coagulation, resulting in reduced flotation recovery and selectivity. In this study, a laboratory prepared gypsum supersaturated solution is used to represent the gypsum supersaturated process water, the effect of gypsum supersaturated solution on the surface properties of silica and sphalerite minerals was investigated using zeta potential distribution measurements, scanning electron microscope (SEM), X-ray photon spectroscopy (XPS), Auger electron spectroscopy (AES), and quartz crystal microbalance with dissipation (QCM-D). Our results show that silica and sphalerite minerals carry identical surface charge (−10 mV of zeta potential) in the gypsum supersaturated solution at pH 10 although they are charged differently in simple electrolyte solution at the same pH. Needle shape gypsum precipitates are found in both silica and sphalerite minerals systems conditioned with gypsum supersaturated solution. The gypsum precipitates do not grow on the minerals surfaces but form in the bulk gypsum supersaturated solution. The heterocoagulation between the examined minerals and gypsum particles is insignificant in the gypsum supersaturated solution. It is the high calcium concentration in the gypsum supersaturated solution that has significant effect on the surface properties of silica and sphalerite minerals. The zeta potentials of silica and sphalerite in a 800 ppm calcium solution (similar to the calcium concentration in the gypsum supersaturated solution) are similar to those measured in the gypsum supersaturated solutions. Both silica and sphalerite minerals surfaces are indiscriminately coated with calcium. The surface coating of calcium results in the identical surfaces between silica and sphalerite minerals, and ultimately causes problems for the flotation separation of silica and sphalerite.     

一水硬铝石和高岭石可浮性的晶体化学分析

从一水硬铝石和高岭石的晶体结构的特征出发,通过对一水硬铝石和高岭石结构中化学键的理论计算及阴离子捕收剂（油酸钠）阳离子捕收剂（十二胺）浮选体系中可浮性的研究,采用矿物晶体化学理论分析了矿物晶体结构特征与可浮性之间的关系,以及产生一水硬铝石和高岭石了性差异的主要原因。     

黄铁矿的吸附性能研究现状及进展

黄铁矿是自然界中储量最丰富的硫化矿之一,常与铅、锌、铜等价值较高的硫化矿共生。针对被高碱抑制的黄铁矿,常使用活化剂改善其可浮性,从而活化选硫,而活化剂对黄铁矿表面性质的影响是研究其作用机理的关键。本文详细阐述了黄铁矿晶体性质,包括其微观晶体结构、能带结构、态密度、Mulliken布局、电化学性质等;以黄铁矿表面物种演变为切入点,介绍了表面杂质掺杂、空位缺陷和表面氧化对其可浮性的影响。综述了离子活化和活化药剂的作用机理：铜、铅离子活化会在黄铁矿表面形成吸附活性位点,促进捕收剂吸附;酸类活化剂会清除黄铁矿表面亲水沉淀和氧化产物;盐类活化剂则会与黄铁矿表面原子反应,改变黄铁矿表面性质和水化层结构,从而促进浮选。加强对活化剂作用过程中黄铁矿表面性质的观察、表征、精确计算和模拟,可为黄铁矿的高效清洁活化剂研发、资源合理利用和环境保护提供一定科学依据。     

A thermochemical study of thiol collector surface reactions on galena and chalcopyrite

The mechanism whereby thiol collectors adsorb onto a mineral surface has been widely studied. Most of these studies examine the mineral surface at equilibrium state and, often, well above monolayer coverage. However, the formation of species at the mineral surface is a complex process that is both kinetically and thermodynamically controlled. In a typical industrial application, the dosage of collector will be around monolayer level. This study uses isothermal titration microcalorimetry to measure the heat evolved during the reaction of sodium ethyl xanthate (SEX) and sodium isobutyl dithiocarbamate (SIBDTC) and their mixtures with galena and chalcopyrite. The sensitivity of the instrument allows heats of reaction of sub-monolayer quantities of thiol collector to be measured.The study found that the nature of the reaction between a collector and a mineral surface was dependent on the type of mineral and the type of collector. Proposals are made for the reactions based on previously reported results and the evidence from this investigation. It was found that when collectors reacted with mixtures of galena and chalcopyrite, the magnitude of the reaction was lower compared to that measured for the pure minerals alone. This may be due to galvanic interactions between the minerals, resulting in a passivating effect on one or both of the minerals.     

Dy和Gd的掺杂对LaMnO3的电输运性质的影响

采用传统的高温固相反应法制备了钙钛矿锰氧化物La1-xRxMnO3(x=0,0.13,R为Dy,Gd,)系列多晶样品。通过X射线衍射(XRD)图谱,电阻率-温度(ρ-T)曲线,研究了该组样品的结构和电输运性质。结果表明：该组样品都具有良好的单相性,属于正交晶系;在所测量的温区内,属于半导体材料,A位的平均离子半径不同,外加磁场对电传导的影响不同;该组样品的ρ-T曲线拟合表明,该组样品在测量的温区内都遵循变程跳跃的导电方式。     

NaOH和机械搅拌对锂辉石表面及浮选行为的影响

NaOH和机械搅拌在锂辉石浮选预处理过程中发挥着重要的作用,为了探明其作用机理,开展了锂辉石单矿物和实际矿石浮选试验,进行了X光电子能谱(XPS)和电感耦合等离子体光谱(ICP)检测分析。结果表明,经过3 000mg/L NaOH用量并施以相应时长和速度的搅拌预处理,可使-0.15+0.074mm粒级的锂辉石单矿物回收率提升70%左右;在相同的3 000mg/L NaOH用量下,静置浸泡和施加叶轮线速度3.93m/s的搅拌。检测分析结果表明,固液分离液中的Si离子浓度增大且矿物表面Al和Li原子相对含量均增大;说明锂辉石矿物表面发生了溶蚀现象,且机械搅拌可以促进其表面的溶蚀,暴露更多的金属阳离子为油酸根在锂辉石表面的吸附提供更多的吸附位点;但表面溶蚀后产生的硅酸盐阴离子组分具有较强的亲水性,吸附于矿物表面,致使单矿物可浮性提升而强化机械搅拌后实际矿石浮选试验中Li2O回收率下降。该研究对锂辉石及硅酸盐矿物浮选预处理的研究具有重要的意义。