Minerals Engineering最新文献_第9页

New insights into the surface chemical properties of serpentine and flotation of pyrite using xanthomonas campestris as a novel selective serpentine depressant: Experimental and DFT investigation 蛇纹石表面化学性质的新认识和利用黄单胞菌作为一种新的选择性蛇纹石抑制剂浮选黄铁矿：实验和DFT研究

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-05 DOI: 10.1016/j.mineng.2024.109141

Levie Mweene , Govinda Prasad Khanal , Emmanuel Etim

The flotation separation of pyrite (Py) from serpentine (Spt) was studied using xanthamonas campestris (XC) as a novel Spt depressant. The adsorption of XC onto Spt and Py was observed to decrease with increase in pH attesting to increased repulsion between the negatively charged carboxylate portion of XC and the increased negativity of the mineral surface. However, the polysaccharide adsorption onto Py was less than that onto Spt due to a higher iso-electric point (IEP) of Spt compared to that of Py. Further, theoretical investigations using quantum theory of atoms in molecules (QTAIM) revealed that XC adsorption onto Spt was due to hydrogen bonding (HB), partial and non-covalent interactions, whereas that onto Py was due to partial covalent and non-covalent interactions. Additionally and in general, the adsorption of XC onto the minerals was due to the shift of electrons from the polysaccharide to mineral surface species. Flotation studies conducted at pH 7.8 of Py-Spt (1:1) in presence of 20 g/t, 80 g/t and 60 g/t of sodium tripolyphosphate (SPP), XC and potassium amyl xanthate (PAX) yielded Py grade and separation efficiency of 98.7 % and 97.8 %, respectively, at an economical cost. Therefore, XC is a potential depressant for Spt.

以黄单胞菌（XC）为新型蛇纹石抑制剂，研究了黄铁矿（Py）与蛇纹石（Spt）的浮选分离。XC在Spt和Py上的吸附随着pH的增加而减少，这证明了XC的带负电的羧酸盐部分与矿物表面负电的增加之间的排斥力增加。然而，由于Spt的等电点（IEP）比Py高，多糖在Py上的吸附比在Spt上的吸附少。此外，利用分子原子量子理论（QTAIM）的理论研究表明，XC在Spt上的吸附是由于氢键（HB）、部分和非共价相互作用，而在Py上的吸附是由于部分共价和非共价相互作用。此外，一般来说，XC在矿物上的吸附是由于电子从多糖转移到矿物表面。在pH为7.8（1:1）的条件下，在20 g/t、80 g/t和60 g/t三聚磷酸钠（SPP）、XC和戊基黄药钾（PAX）的存在下，Py- spt的浮选效率分别为98.7%和97.8%，且成本经济。因此，XC是一种潜在的Spt抑制剂。

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引用次数: 0

A new mixture of anionic collectors for improvement of apatite floatability 一种改善磷灰石可浮性的新型阴离子捕收剂混合物

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-03 DOI: 10.1016/j.mineng.2024.109129

Saeed Abdollahi , Sajjad Afraei , Akbar Mehdilo , Reza Kouchakzadeh , Mehdi Irannajad

Flotation is the most essential method for the concentration of phosphate reserves and, hence, the production of apatite concentrate. With the reduction of high-grade reserves and the necessity of exploiting low-grade phosphate ores, many efforts have been made to use different chemical reagents alone and their combinations as collectors for apatite flotation and achieving high-quality concentrates for preparing phosphoric acid and fertilizers. This work focuses on applying direct apatite flotation by employing a novel mixture of fatty acid collectors to optimize the apatite processing plants. Extensive experiments using tall oil fatty acid (TOFA) and oleic acid polyethylene glycol ester 6 mol (OAPEGE6) alone and their mixture in different ratios were conducted in micro-flotation, bench flotation, and plant flotation scales. The micro-flotation experiments showed that using OAPEGE6 and TOFA, the flotation recovery of apatite at a pH of 9.5 is 46% and 86%, respectively. However, by mixing TOFA and OAPEGE6 in a weight ratio of 70% to 30%, the flotation recovery of apatite increases to 95%. At this weight ratio of TOFA and OAPEGE6 using a 600

g / t

mixed collector, an apatite concentrate containing 23.2%

P_{2} O_{5}

with a recovery of 90.4% is achieved by rougher stage bench flotation in laboratory experiments. Finally, using the mixed collector with the formulation mentioned above on a plant-scale, an apatite concentrate with almost 33%

P_{2} O_{5}

and 59% recovery is obtained through rougher and cleaner stages of the flotation process. FTIR analysis and zeta potential measurements show that the simultaneous presence of TOFA and OAPEGE6 with a synergetic effect can strengthen the chemisorption of oleate active species on the apatite surface. As confirmed by contact angle measurements, this improved the formation of an insoluble hydrophobic layer on the apatite surface and resulted in its flotation recovery.

浮选是浓缩磷酸盐储备，从而生产磷灰石精矿的最基本方法。随着高品位储量的减少和开发低品位磷矿的必要性，人们尝试单独或组合使用不同的化学试剂作为捕收剂浮选磷灰石，获得用于制磷酸和肥料的高质量精矿。本文主要研究了采用一种新型脂肪酸捕收剂混合浮选磷灰石，以优化磷灰石选矿厂。在微浮选、台浮和浮选装置中，分别对托尔特油脂肪酸（TOFA）和油酸聚乙二醇酯6 mol （OAPEGE6）单独及其不同配比的混合物进行了广泛的实验研究。微浮选实验表明，OAPEGE6和TOFA在pH = 9.5时，磷灰石的浮选回收率分别为46%和86%。而将TOFA与OAPEGE6以70% ~ 30%的质量比混合后，磷灰石的浮选回收率可提高到95%。采用600 g/t的混合捕收剂，在TOFA与OAPEGE6重量比相同的条件下，通过粗段台架浮选，获得了P2O5含量为23.2%、回收率为90.4%的磷灰石精矿。最后，采用上述配方的混合捕收剂，通过浮选过程的粗选和精选两个阶段，获得了P2O5含量接近33%、回收率59%的磷灰石精矿。FTIR分析和zeta电位测量结果表明，TOFA和OAPEGE6同时存在，协同作用增强了油酸活性物质在磷灰石表面的化学吸附。接触角测量证实，这促进了磷灰石表面不溶性疏水层的形成，并导致其浮选回收。

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引用次数: 0

Sustainable reprocessing of Pb–Zn mine tailings through froth flotation for resource recovery and environmental remediation in abandoned mining regions 泡沫浮选可持续再处理铅锌矿尾矿对废弃矿区资源回收和环境修复的影响

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-11-29 DOI: 10.1016/j.mineng.2024.109132

Abdessamad Khalil , Yassine Ait-khouia , Hamza Beniddar , Mustapha El Ghorfi , Rachid Hakkou , Yassine Taha , Mostafa Benzaazoua

The abandoned Touissit-Bou Beker mining district has accumulated tens of millions of tons of tailings, stored without environmental safeguards. Due to the limited ore processing method, the tailings exhibit a significant zinc (2 wt%) and lead (0.3 wt%) content, mainly buried in carbonate minerals. These tailings pose environmental concerns but also offer economic opportunities. This study investigated the feasibility of decontaminating these tailings using froth flotation to produce a clean mineral byproduct. Composite samples were collected via reverse circulation (RC) drilling, and flotation conditions were optimized. Quantitative mineralogy and environmental behavior were assessed using quantitative evaluation of materials by scanning electron microscope (QEMSCAN®) and toxicity characteristic leaching procedure (TCLP), respectively. Under optimal conditions — potassium amyl xanthate (KAX) 350 g/t, CuSO₄ 1,250 g/t, Na₂S 1,250 g/t, sodium hexametaphosphate (SH) 1,750 g/t, and pH 11—Zn and Pb recoveries reached up to 94 % and 71 %, respectively. Residual Pb–Zn remained partially locked within the non-sulfide gangue minerals or present as slime particles. TCLP results indicate minimal risk, suggesting reprocessing mine tailings in abandoned mine sites in Morocco could offer economic and environmental benefits. The current study is expected to serve as a reference for decision-makers when evaluating sustainable management options for mine tailings.

废弃的Touissit-Bou Beker矿区积累了数千万吨的尾矿，这些尾矿在没有环境保护的情况下储存。由于选矿方法的限制，尾矿中锌（2 wt%）和铅（0.3 wt%）含量显著，主要埋藏在碳酸盐矿物中。这些尾矿带来了环境问题，但也提供了经济机会。本研究探讨了采用泡沫浮选法对尾矿进行除污以生产清洁矿物副产物的可行性。采用反循环钻孔法采集复合样品，并对浮选条件进行优化。分别采用扫描电子显微镜（QEMSCAN®）和毒性特征浸出程序（TCLP）对材料进行定量评价，评估定量矿物学和环境行为。在最佳条件下，戊基黄药钾（KAX） 350 g/t, CuSO4 1250 g/t, Na2S 1250 g/t，六偏磷酸钠（SH） 1750 g/t, pH 11，锌和铅的回收率分别达到94%和71%。残余的铅锌部分被锁在非硫化物脉石矿物中或以泥颗粒的形式存在。TCLP结果表明风险很小，这表明在摩洛哥的废弃矿场对尾矿进行再加工可以提供经济和环境效益。本研究可望为决策者评价尾矿可持续管理方案提供参考。

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引用次数: 0

Model investigation of a dry vibrated fluidized sinkhole system for separating coarse particles based on density 基于密度的干式振动流态化沉孔粗颗粒分离系统模型研究

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-11-29 DOI: 10.1016/j.mineng.2024.109111

Dusan Ilic, Aleksej Lavrinec, Kevin P. Galvin

A simulation model of a dry, vibrated, fluidized medium (VFM) with sinkhole arrangement was developed and used to investigate the separation of relatively dense, coarse particles. The objective of the new model was to emulate a most unusual experimental result involving the sinkhole arrangement, separation densities much higher than the bulk density of the fluidized medium. The VFM was simulated using spherical sand particles

225 μ m

in diameter, and density of 2500 kg/m³, while spherical coarse particles 2 to 4 mm in diameter, with density ranging from 2100 to 8400 kg/m³, were used as the density tracers. Coupled computational fluid dynamics (CFD)/discrete element method (DEM) was used to simulate interactions for up to 10 s duration. Remarkably, the model reproduced separation densities much higher than the bulk density of the suspension. Different combinations of frequency and amplitude of vibration, air flow velocity, and volume of VFM were used. The separation density was found to scale directly with the amplitude, and scale with the frequency to the 0.33 power. Vibration intensity correlated poorly with separation density. The critical condition governing the tendency of a particle to float or sink was examined in terms of the volume fraction and the density of the bed profile in the vicinity of the sinkhole. A pronounced reduction in the bed density is evident near the base of the VFM for particles that sink. The average solid volume fraction is observed to vary from 0.58 during initial settling, decreasing as the particles sink. Interestingly, re-circulation of the VFM is needed for a tracer particle to sink. Re-circulation is dependent on, and increases with, airflow as the bed expands up to a maximum beyond which it again reduces.

建立了一种干燥、振动、流化介质（VFM）的模拟模型，并将其用于研究相对致密、粗颗粒的分离。新模型的目的是模拟一个最不寻常的实验结果，涉及天坑排列，分离密度远高于流化介质的堆积密度。采用直径为225μm、密度为2500 kg/m3的球形沙粒模拟VFM，采用直径为2 ~ 4mm、密度为2100 ~ 8400 kg/m3的球形粗颗粒作为密度示踪剂。采用计算流体力学(CFD)/离散元法（DEM）耦合模拟了长达10 s的相互作用。值得注意的是，该模型再现的分离密度远高于悬浮液的堆积密度。采用不同的振动频率和振幅、气流速度和VFM体积组合。分离密度与振幅成正比，与频率成0.33次方。振动强度与分离密度相关性较差。根据沉降孔附近床层剖面的体积分数和密度，研究了控制颗粒漂浮或下沉趋势的临界条件。对于下沉的颗粒，在VFM的底部附近，床层密度明显降低。平均固体体积分数在初始沉降时为0.58，随着颗粒下沉而减小。有趣的是，示踪粒子下沉需要VFM的再循环。再循环依赖于气流，并随着气流的增加而增加，当床层膨胀到最大值时，再循环又会减少。

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引用次数: 0

Advancements in the extraction of niobium and tantalum: Innovative strategies in hydrometallurgical processes 铌和钽的提取进展：湿法冶金工艺的创新策略

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-11-29 DOI: 10.1016/j.mineng.2024.109125

Darwin Michell Cheje Machaca, Thamyres Cardoso de Carvalho, Jorge Alberto Soares Tenório, Denise Crocce Romano Espinosa

This article presents a comprehensive analysis of the challenges and advancements in the extraction of niobium (Nb) and tantalum (Ta), focusing on global production and the growing demand for strategic and critical metals. The extraction of these metals from their primary and secondary resources is carried out through well-known metallurgical techniques, based on the use of hydrofluoric acid in the various production chains. However, the operational processes and their sustainable production are hindered due to the negative impacts produced during the process, resulting in a particular challenge for the extraction of these two metals. Therefore, pyrometallurgical and hydrometallurgical processes have been explored as emerging alternatives to the existing commercial processes. Thermal treatment processes in acidic and alkaline media have been shown to be capable of preparing PLS loaded with the metals of interest. On the other hand, leaching using mineral and organic acids is essential for the efficient recovery of Nb and Ta, highlighting their advantages and limitations. Additionally, the precipitation of acidic or basic liquors from hydrometallurgy is described to advance towards selective recovery stages. In this context, emphasis is placed on traditional and novel extractants according to their separation function, to ensure the high quality of the products through current technology.

本文全面分析了铌（Nb）和钽（Ta）的提取面临的挑战和进展，重点关注全球生产和对战略和关键金属不断增长的需求。从初级和次级资源中提取这些金属是通过著名的冶金技术进行的，其基础是在各个生产链中使用氢氟酸。然而，由于过程中产生的负面影响，操作过程及其可持续生产受到阻碍，导致这两种金属的提取面临特别挑战。因此，已经探索了火法冶金和湿法冶金工艺作为现有商业工艺的新兴替代方案。在酸性和碱性介质中的热处理工艺已被证明能够制备负载感兴趣的金属的PLS。另一方面，利用无机酸和有机酸进行浸出是有效回收铌和钽的必要条件，突出了它们的优点和局限性。此外，还描述了湿法冶金中酸性或碱性液的沉淀，以推进选择性回收阶段。在此背景下，重点介绍了传统萃取剂和新型萃取剂的分离功能，通过现有技术确保产品的高质量。

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引用次数: 0

Application of inclined channels in the hydrodynamic classification of minerals by particle size – Extension to coarser separations 倾斜通道在按粒度对矿物进行水动力分类中的应用。推广到较粗的分选

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-11-29 DOI: 10.1016/j.mineng.2024.109114

J.B. Starrett, K.P. Galvin

A REFLUX™ Classifier was used to classify a silica feed (0–710 µm) based on particle size. Split Fluidisation was used to generate remarkably sharp separations involving solids throughputs of up to 92 t/m²/h. This work builds on the previous study by Starrett and Galvin (2023) but with a focus on coarser separations at higher throughputs. As the separation size increased, there was increasing misplacement of fine particles in excess of 75 µm into the coarse underflow stream. This problem was averted by halving the cross-sectional area of the lower section of the REFLUX™ Classifier. This change led to a doubling of the superficial fluid velocity in the lower section for a given set of flow rates, ensuring fine particles were unable to settle into the coarse underflow. In general, the separations performed in this study show complete closure of the partition curve at both the coarse and fine ends. It was also found that to deliver sharp separations it is essential to introduce sufficient water to the separator, per unit of solids transport to the overflow, especially for higher solids throughputs with coarser separations. Although the fluidisation rate can be used to control the separation size at finer separations (below 180 µm) and lower throughputs, ultimately the bias flux provides the basis for controlling the separation size at coarser sizes and higher throughputs.

使用REFLUX™分类器根据粒度对二氧化硅进料（0-710µm）进行分类。劈裂流化用于产生非常尖锐的分离，涉及固体吞吐量高达92 t/m2/h。这项工作建立在Starrett和Galvin（2023）之前的研究基础上，但重点是在更高通量下的粗分离。随着分离粒度的增大，超过75µm的细颗粒在粗底流中的错位量增加。通过将REFLUX™分级器下部的横截面积减半，避免了这个问题。在给定的一组流量下，这种变化导致下部的表面流体速度增加一倍，确保细颗粒无法沉降到粗底流中。总的来说，在本研究中进行的分离显示在粗端和细端分配曲线完全闭合。研究还发现，为了实现尖锐的分离，必须向分离器引入足够的水，每单位的固体输送到溢流，特别是对于较高的固体吞吐量和较粗的分离。虽然流化速率可以用来控制细粒度（小于180µm）和低通量的分离粒度，但最终偏压通量为控制粗粒度和高通量的分离粒度提供了基础。

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引用次数: 0

Exploring the influence of surface roughness on the interface phenomenon between an air bubble and a glass bead: An experimental and theoretical investigation 探讨表面粗糙度对气泡与玻璃珠界面现象的影响：实验与理论研究

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-11-29 DOI: 10.1016/j.mineng.2024.109126

Mianyan Yang, Zhijun Zhang

The effect of surface roughness on the detachment between the bubbles and the glass beads (soda-lime) was comprehensively investigated. Glass beads with dimensions of −1.20 + 1.12 mm were acid etched to achieve varying degrees of surface roughness, followed by silanation reactions conducted for different immersion times. The characterization of surface roughness was conducted using a ContourGT-K 3D optical microscope. Measurements of receding contact angle, induction time and detachment force were conducted to assess the influence of surface roughness on bubble and glass bead attachment/detachment. It is observed that the etching surface of glass beads with uniform protrusions and depressions, the hydrophobic glass beads exhibited shorter induction time, larger contact angle and higher critical detachment force. However, the stability of aggregates of bubbles and hydrophilic glass beads was reduced, making them prone to detachment. Moreover, larger protrusions and depressions on hydrophobic glass bead surfaces with increasing etching time, resulted in an increase in induction time, a decrease in receding contact angle and critical detachment force. The stability of bubbles and hydrophilic glass bead aggregates remained unchanged.

研究了表面粗糙度对气泡与玻璃微珠（钠石灰）分离的影响。对尺寸为- 1.20 + 1.12 mm的玻璃微珠进行酸蚀，获得不同程度的表面粗糙度，然后进行不同浸泡时间的硅化反应。采用ContourGT-K三维光学显微镜对表面粗糙度进行表征。通过测量后退接触角、诱导时间和分离力来评估表面粗糙度对气泡和玻璃珠附着/分离的影响。观察到玻璃微珠的蚀刻表面具有均匀的凹凸，疏水玻璃微珠表现出更短的诱导时间、更大的接触角和更高的临界脱离力。然而，气泡和亲水玻璃珠聚集体的稳定性降低，使它们容易脱落。随着刻蚀时间的增加，疏水玻璃珠表面的凸起和凹陷增大，导致感应时间增加，后退接触角和临界脱离力减小。气泡和亲水性玻璃珠聚集体的稳定性保持不变。

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引用次数: 0

Flotation separation of molybdenite from talc using carrageenan as depressant 用卡拉胶作抑制剂浮选分离辉钼矿和滑石

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-11-28 DOI: 10.1016/j.mineng.2024.109122

Chao Li, Chao Wang, Fei Wu, Guangli Zhu, Yijun Cao, Shaohang Cao

Due to the strong natural floatability of molybdenite and talc, conventional flotation depressants are difficult to separate these two minerals. As a common depressant, starch has a strong inhibitory effect on both minerals (Castro et al., 2016), while sodium carboxymethyl cellulose has a weak inhibitory effect on both minerals (Chen et al., 2024). Therefore, selecting a proper depressant is the key for achieving the efficient flotation separation. This study investigated the flotation separation of talc and molybdenite using carrageenan as the depressant and sodium butyl xanthate (SBX) as the collector. The micro-flotation test results showed that carrageenan exhibited a strong depressing effect on both talc and molybdenite, and even stronger on molybdenite. However, molybdenite could achieve flotation after adding SBX, while talc was still suppressed. In addition, it was observed that the recovery of molybdenite by adding SBX first was higher than that of adding carrageenan first. A concentrate with a molybdenum grade of 50.64% and recovery of 87.34% was obtained in the artificial ore flotation with the initial grade of 28.52%. The adsorption mechanism of carrageenan on the surfaces of molybdenite and talc was studied using contact angle testing, adsorption capacity testing, zeta potential measurement, Scanning Electron Microscopy-Energy Dispersive Spectrometer (SEM-EDS) analysis, Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) analysis. It was concluded that carrageenan physically adsorbs on both mineral surfaces, whereas SBX adsorbs selectively on the surface of molybdenite and competes with carrageenan for adsorption.

辉钼矿和滑石具有较强的天然可浮性，常规浮选抑制剂难以将两者分离。淀粉作为一种常见的抑制剂，对这两种矿物质都有较强的抑制作用（Castro et al., 2016），而羧甲基纤维素钠对这两种矿物质的抑制作用较弱（Chen et al., 2024）。因此，选择合适的抑制剂是实现浮选高效分离的关键。以卡拉胶为抑制剂，丁基黄药钠（SBX）为捕收剂，研究了滑石和辉钼矿的浮选分离。微浮选试验结果表明，卡拉胶对滑石和辉钼矿均有较强的抑制作用，对辉钼矿的抑制作用更强。而加入SBX后辉钼矿可实现浮选，而滑石仍有抑制作用。另外，先加入SBX的辉钼矿回收率高于先加入卡拉胶的辉钼矿回收率。人工浮选获得了钼品位为50.64%、钼回收率为87.34%的精矿，初始品位为28.52%。采用接触角测试、吸附量测试、zeta电位测试、扫描电镜-能谱仪（SEM-EDS）分析、傅里叶变换红外光谱（FTIR）分析和x射线光电子能谱（XPS）分析等方法研究了卡拉胶在辉钼矿和滑石表面的吸附机理。结果表明，卡拉胶在辉钼矿表面均有吸附作用，而SBX则在辉钼矿表面选择性吸附，并与卡拉胶竞争吸附。

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引用次数: 0

Producing green rutile from secondary ilmenite via hydrogen reduction 通过氢还原法从二级钛铁矿中生产绿色金红石

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-11-26 DOI: 10.1016/j.mineng.2024.109113

William Spencer, Don Ibana, Pritam Singh, Aleksandar N. Nikoloski

The use of coal for ilmenite reduction to produce synthetic rutile is widespread in industry. However, the carbon dioxide emissions associated with coal combustion pose significant environmental concerns. Alternative reductants such as hydrogen have the potential to promote environmentally friendly production of green rutile. This study aimed to assess the technical feasibility of reducing an Australian secondary (weathered) ilmenite using hydrogen, focusing on the effects of reduction temperature and time. The ilmenite was composed of 65 % titanium dioxide, 29 % iron oxide, and 6 % impurities. Samples at each stage of the processing were analysed using X-ray fluorescence spectrometry (XRF) and scanning electron microscopy (SEM). The results revealed that both temperature and time impacted ilmenite reduction, with increasing values of both parameters leading to higher reduction percentages. The maximum reduction percentages were obtained for a reduction time of 240 min at all temperatures, and there was an increase from 62 % at 973 K to 99 % at 1273 K for this reduction time. A reduction percentage of 90 % was obtained at 1273 K with a holding time of 60 min. This study indicates that a minimum temperature of 1073 K is required to achieve a reduction exceeding 90 % for secondary ilmenite. The SEM analysis showed that fine, discrete, metallised iron particles were present on the surface of the reduced secondary ilmenite. The investigation into hydrogen as an alternative reductant demonstrated improved iron–titanium separation in acid leaching compared with the conventional reduction method using coal and resulted in green rutile products with titanium dioxide grades exceeding 96 %, and iron oxide content below 1 %.

工业上普遍使用煤来还原钛铁矿以生产合成金红石。然而，与煤炭燃烧相关的二氧化碳排放会带来严重的环境问题。氢气等替代还原剂有可能促进环保型绿色金红石的生产。本研究旨在评估使用氢气还原澳大利亚二级（风化）钛铁矿的技术可行性，重点关注还原温度和时间的影响。钛铁矿由 65% 的二氧化钛、29% 的氧化铁和 6% 的杂质组成。使用 X 射线荧光光谱仪（XRF）和扫描电子显微镜（SEM）分析了每个加工阶段的样品。结果表明，温度和时间都会影响钛铁矿的还原，这两个参数值越大，还原率越高。在所有温度下，当还原时间为 240 分钟时，还原率最高，从 973 K 时的 62% 增加到 1273 K 时的 99%。在保持 60 分钟的情况下，1273 K 的还原率为 90%。这项研究表明，要使二次钛铁矿的还原率超过 90%，最低温度为 1073 K。扫描电镜分析表明，还原后的二次钛铁矿表面存在细小、离散的金属化铁颗粒。对氢气作为替代还原剂的研究表明，与使用煤炭的传统还原方法相比，在酸浸出过程中铁钛分离效果更好，生产出的绿色金红石产品二氧化钛品位超过 96%，氧化铁含量低于 1%。

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引用次数: 0

New insights into the significant drop of molybdenite flotation Recovery: The Overlooked oxidation of MoS2 basal facet 关于辉钼矿浮选回收率大幅下降的新见解：被忽视的 MoS2 基底面氧化作用

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-11-26 DOI: 10.1016/j.mineng.2024.109131

Dashi Lei , Yuen Yan , Songbo Ma , Xiaoliang Zhang , Xiangyu Peng , Yubin Wang , Yangge Zhu

The oxidation of molybdenite in water-oxygen system adversely affects the flotation recovery. However, previous studies primarily focused on the oxidation of MoS₂ edge surfaces, neglecting the oxidation of basal facets, which constitute a larger proportion of the overall surface area. In this work, we systematically investigated the oxidation behavior of the molybdenite base surface and explored the influence of base surface oxidation sites on flotation behavior. The results demonstrated that surface oxidation of molybdenite leaded to a negative surface potential, decreased hydrophobicity and reduced dodecane adsorption. Electrostatic potential (ESP) and density functional theory (DFT) calculations revealed that oxidation sites on the molybdenite surface exhibited a strong negative charge, enhancing the adsorption of water molecules while weakening kerosene adsorption. Molecular dynamics (MD) simulations indicated that the oxidized molybdenite surface formed a hydration layer with thickness of ∼ 6 nm, which impedes dodecane adsorption. Moreover, this study proposed an effective strategy to improve molybdenite flotation recovery, that is reducing the concentration of dissolved oxygen in the pulp to inhibit MoS₂ oxidation. These findings provide new insights into the oxidation behavior of molybdenite, and contribute to a better understanding of its flotation behavior in pulp.

辉钼矿在水氧系统中的氧化会对浮选回收率产生不利影响。然而，以往的研究主要关注 MoS2 边缘表面的氧化，而忽略了占整体表面积较大比例的基底面的氧化。在这项工作中，我们系统地研究了辉钼矿基面的氧化行为，并探讨了基面氧化点对浮选行为的影响。结果表明，辉钼矿的表面氧化会导致负表面电位、疏水性降低和十二烷吸附量减少。静电电位（ESP）和密度泛函理论（DFT）计算显示，辉钼矿表面的氧化位点表现出强烈的负电荷，增强了对水分子的吸附，同时削弱了对煤油的吸附。分子动力学（MD）模拟表明，氧化的辉钼矿表面形成了厚度为 6 nm 的水合层，阻碍了对十二烷的吸附。此外，该研究还提出了提高辉钼矿浮选回收率的有效策略，即降低矿浆中溶解氧的浓度以抑制 MoS2 氧化。这些发现为了解辉钼矿的氧化行为提供了新的视角，有助于更好地理解辉钼矿在矿浆中的浮选行为。

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