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Minerals Engineering
Pergamon Press, Inc.,
Minerals Engineering

Pergamon Press, Inc.,

0892-6875

Minerals Engineering/Journal Minerals EngineeringSCIISTPEI
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    Effect of pre-oxidation on galena in the flotation separation of chalcopyrite from galena with calcium lignosulfonate as depressant

    Su, ChaoCai, JinpengYu, XingcaiPeng, Rong...
    11页
    查看更多>>摘要:In this work, to achieve efficient separation of chalcopyrite from galena in Cu-Pb sulfide minerals, pre-oxidation by sodium persulfate (Na2S2O8) was used to magnify the differences in the floatability of two minerals in the presence of calcium lignosulfonate (CLS). The micro-flotation results of chalcopyrite and galena showed that pre-oxidation by Na2S2O8 could strengthen the depression performance of CLS on galena. The strengthening mechanism of Na2S2O8 to CLS adsorption onto the galena surface was revealed by local electrochemical impedance spectroscopy (LEIS), zeta-potential analysis, and X-ray photoelectron spectroscopy (XPS). LEIS showed that oxidation by Na2S2O8 contributed to the adsorption of CLS on the galena surface. XPS analysis demonstrated that the main oxidation species on the galena surface were PbSO4 and Pb(OH)(+) in the presence of Na2S2O8 and that CLS interacted with oxidized galena by chemisorption. Zeta potential analysis indicated that a positive oxidation species was adsorbed on the galena surface; moreover, the oxidation species Pb(OH)(+) endowed CLS on the galena surface with excellent adsorption performance. These findings are also supported by the results of the solution chemistry calculation. Galena also exhibits terrible surface reactivity and responds poorly to xanthate collectors after interaction with Na2S2O8 and CLS.

    Pilot-scale microfluidic solvent extraction of high-value metals

    Yang, DaisyKashani, Moein NavvabPriest, Craig
    7页
    查看更多>>摘要:Numbering-up of processing units is essential for industrial-scale microfluidic solvent extraction. In the present work, a multistream microchip was numbered-up to successfully extract high-value metals (including platinum and rare earth elements) from industrial leach solutions. The platform provides orders of magnitude higher throughput (up to 1 L/h) compared with previously reported stream-based microfluidic solvent extraction, without compromising extraction performance. Extraction efficiency was monitored with increasing throughput. The approach to steady state in a three-stage counter-current extraction circuit was monitored by pH and inductively coupled plasma mass spectrometry of the aqueous raffinate. This pilot-scale microfluidic solvent extraction shows potential for refining high-value (technology or precious) metals and as a laboratory tool for rapid screening of reagents and process conditions.

    Review on metal extraction technologies suitable for critical metal recovery from mining and processing wastes

    Whitworth, Anne J.Vaughan, JamesSoutham, Gordonvan der Ent, Antony...
    15页
    查看更多>>摘要:The transition to low-carbon economies, advancements in high-tech and rapid uptake of electronic equipment will see increased demand over the coming decades for so-called "critical " metals: metals considered important to society and that are vulnerable to supply disruption. Consequently, there is now a global drive to find and develop critical metal resources. Significant concentrations of critical metals have reported to mining and pro-cessing wastes over time due to a range of factors, including unfavourable economics and unsuitable processing infrastructure. With expanding scope and scale of markets, mining and processing wastes now represent a largely un-tapped resource of critical metals. The reclamation of critical metals from solid mining and processing wastes involves mineral processing, metal extraction, and metal recovery. Metal extraction involves the separation of metals from a metal-bearing material using chemical reactions. Metal extraction from solid mining and pro-cessing wastes largely relies on established processing techniques. However, the overall process configuration can differ greatly from conventional primary production methods, and there is often an opportunity to streamline the reprocessing of wastes where the original production process has already done some of the required physical or chemical work. This review provides an overview of seven technologies: atmospheric leaching, pressure leaching, bioleaching, resin-in-pulp, pyrometallurgy, phytomining and solvometallurgy, that are suitable for extracting specific critical metals from solid mining and processing wastes. Eleven critical metals are considered in this review: cobalt, gallium, germanium, indium, lithium, nickel, rhenium, tellurium, tin, tungsten, and va-nadium. The approaches discussed are important for the extraction of critical metals from mining and processing wastes now and into the future.

    A theoretical and experimental study of the effects of NaCl and the competitive chemisorption of ions at the surface sites in the context of galena flotation

    Nowosielska, Anna M.Nikoloski, Aleksandar N.Parsons, Drew F.
    10页
    查看更多>>摘要:In this study we have investigated the effects of increasing the NaCl concentration on the flotation of galena. Experiments were carried out using a Hallimond tube in NaCl solutions with concentrations of 1, 10 and 100 mM, at pH 9. It was found that the recovery of galena by collector-less flotation improved for higher NaCl concentrations. Zeta potential measurements made on galena particles conditioned in NaCl solutions were used to calibrate the parameters for describing a chemisorption model representing charge regulation at the galena binding sites. Our galena chemisorption model presented here is a "two-site/not amphoteric" surface complexation model. A chemisorption model representing the charge regulation process on the surface of an air bubble has also been applied. The zeta potentials calculated using these models were in agreement with the measured values, indicating that these models can be applied to predict the potentials on the surface of galena and an air bubble for a range of NaCl concentrations and pH. To investigate the mechanisms of particle-bubble interactions for each NaCl concentration, the total interaction free energy as a function of the separation distance between galena and an air bubble was determined. It was found that at a NaCl concentration of 1 mM, due to adsorption of ions at the galena surface, repulsion dominated the interaction, and the lowest galena recovery was reported. With an increase in NaCl concentration in solution to 100 mM, the total interaction between galena and an air bubble was represented by a purely attractive total interaction free energy curve. The theoretical predictions of the models supported the experimental results, with a stronger attraction predicted by the models at higher ionic concentrations, corresponding to a higher galena recovery during flotation.

    Modeling the distribution of an adsorbing solute in a catalyzed column

    Krishnamoorthy, PrashanthDixon, David G.Ren, ZiheMora, Nelson...
    15页
    查看更多>>摘要:Catalytic solutes have been reported to significantly enhance dissolution rates of copper from chalcopyrite. Ethylene thiourea (ETu), a thiocarbonyl compound which has been shown to have such a catalytic effect, is used as a model solute to study the distribution of solute in a column of crushed ore under a point source to simulate the effects of a single drip emitter. Steady state infiltration tests of ETu solution are performed to generate ETu breakthrough curves which are compared with curves from metal ions such as copper and lithium to estimate solute transport properties such as adsorption and reaction. The Redlich-Peterson isotherm is used successfully to describe the adsorption behavior of ETu in a column of crushed ore. A 2D axisymmetric model of solute transport is used to estimate adsorption and reaction rate constants by analyzing the sensitivity of model break through curves and comparing them to experimental results. Further, the model populated with the computed parameters is used to estimate ETu breakthrough curves resulting from varying input concentrations, column heights and infiltration rates.

    Pulsation curves strengthen the high gradient magnetic separation process: Experimental study and simulation explanation

    Hu, ZhichengXue, ZixingWang, YuhuaLu, Dongfang...
    13页
    查看更多>>摘要:The pulsating slurry high gradient magnetic separator (PHGMS) has been widely used for the separation of feebly magnetic materials. As the main competing force, pulsating slurry effectively overcomes matrix blockage and affects the buildup behavior of particles. At present, the used pulse shape in PHGMS constitutes a sinusoidal harmonic vertical motion in which the duration and intensity of the impulsion and suction strokes are similar. However, other pulsation profiles, such as, trapezoidal shape and saw-tooth shape pulses, can also be obtained depending on the stratification mechanism. There is little literature to focus on how pulse shape influences the performance of PHGMS. The change of curve could be a method worth exploring to improve the separation. In this paper, the asymmetry pulsating curves are obtained by switching the velocity of the step motor during one cycle. Then, the single-wire experiments, single-wire 2D numerical simulation and multi-wires experiments are presented to indicate the effect of different pulse shapes. In single-wire experiments, compared with the traditional sinusoidal harmonic curve, the asymmetry pulsating curves have a higher grade, finer particle buildup, but lower accumulation volume. The curves of the rapid downward stroke and slow upward stroke are better than the inverse movement curve in asymmetry pulsation. The results of separating the up and downstream accumulations on the magnetized wire and numerical simulation reveal that these effects can be attributed to the direction of net force and vortex strengthening. The trajectory simulation of multi-component obtains a similar result with single-wire experiments to confirm the superiority of rapid downward stroke and slow upward stroke in selectivity. However, in multi-wires experiments, due to the matrix blockage the curves of rapid upward stroke and slow upward stroke show the greater potential advantages in both grade and weight compared with other curves at condition of high feed velocity.

    Selective depression of Pb2+-activated sphalerite by potassium ferricyanide in Pb-Zn sulfides flotation separation

    Liu, YangWei, ZhicongXue, Chen
    12页
    查看更多>>摘要:The depression of sphalerite in the flotation separation of galena and sphalerite is usually difficult, especially when sphalerite is activated by Pb2+ ions dissolved from lead-bearing minerals. In this study, the cheap, efficient, and environmentally friendly regent of potassium ferricyanide (K-3[Fe(CN)(6)]) was used for the first time to efficiently separate galena from Pb2+ -activated sphalerite at neutral pH. Micro-flotation experiments, adsorption tests, contact angles, zeta potential analysis, X-ray photoelectron spectroscopy (XPS) analysis, and time-of-flight secondary ion mass (ToF-SIMS) were performed to investigate the depression mechanism of K-3[Fe(CN)(6)]. The micro-flotation test results showed that K-3[Fe(CN)(6)] had a considerable depression effect on Pb2+-activated sphalerite. Adsorption tests showed that competitive adsorption between K-3[Fe(CN)(6)] and sodium butyl xanthate (SBX) on the sphalerite surface reduced the amount of SBX adsorbed on the surface of Pb2+ -activated sphalerite, thereby depressing sphalerite. Contact angles analysis indicated that K-3[Fe(CN)(6)] treatment reduced the contact angle of Pb2+-activated sphalerite surface and weakened its hydrophobicity, providing a favorable condition for the separation of galena and Pb2+-activated sphalerite. Zeta potential measurements suggested that the KAFe (CN)(6)] effectively prevented the adsorption and interaction of sodium butyl xanthate (SBX) on the surface of Pb2+-activated sphalerite. Time-of-flight secondary ion mass (ToF-SIMS) and XPS analysis indicated that K-3[Fe(CN)(6)] could chemisorb onto the Zn sites on the surface of Pb2+-activated sphalerite and form hydrophilic precipitates containing Zn-3[Fe(CH)(6)](2), Zn3K2[Fe(CN)(6)](2), and Pb(OH)(2), which further generate a hydrophilic passivation layer, and reduced the floatability of Pb2+-activated sphalerite.

    The selective flotation separation of rhodochrosite against quartz and calcite with dicarboxylic amino acid-based surfactants as a novel collector

    Sun, HongyuWang, ShuaiFei, LingyunCao, Zhanfang...
    12页
    查看更多>>摘要:Rhodochrosite is often associated with calcium- and silicon-bearing minerals, resulting in a low grade, and it is difficult to achieve efficient flotation separation with conventional collectors. A novel collector, 2-decanoylamino-pentanedioic acid (DPA), was synthesized by constructing an amide group and double-branched carboxylic acid molecular structure to selectively separate rhodochrosite against quartz and calcite. The flotation results demonstrated that, compared with sodium oleate, DPA exhibited superior collecting performance and enabled the separation of rhodochrosite from quartz and calcite under neutral pH, with no addition of a foaming agent or activator; thus, DPA is regarded as an appropriate flotation collector for rhodochrosite. Analysis of the contact angles, Fourier transform infrared spectroscopy (FTIR), zeta potential and X-ray photoelectron spectroscopy (XPS) results showed that DPA chemically adsorbed on the surface of rhodochrosite, forming 8-membered ring or two 4-membered ring structures. However, no significant interaction was detected on the surface of quartz and calcite, providing evidence for the flotation separation of rhodochrosite from calcite and quartz. This research provides a potential collector for efficient utilization of rhodochrosite.

    Application of macromolecular organic polymer S-7261A in arsenic removal by flotation of refractory mixed copper ore

    Liao, XingjinChen, YeChen, Jianhua
    4页
    查看更多>>摘要:An organic compound S-7261A exhibiting satisfactory selectivity and powerful depression on arsenopyrite was introduced to replace sodium sulfite (Na2SO3) in the separation of Cu-S-As bulk concentrate in Yunnan Datun Mill. The results of batch flotation tests indicated its excellent selective depressing power on both pyrite and arsenopyrite in the flotation separation of Cu-S-As bulk concentrate. The comparison tests of the pilot showed an evident improvement in the flotation index of copper and arsenic. With S-7261A replacing Na2SO3, Cu recovery was increased by 9.73%, As content being reduced to 1.02% in copper concentrate.

    Quantitative analysis of ore texture breakage characteristics affected by loading mechanism: Fragmentation and mineral liberation

    Parapari, Parisa SemsariParian, MehdiRosenkranz, Jan
    13页
    查看更多>>摘要:Mineral liberation as the main purpose of comminution in ore beneficiation is not applied in the design of comminution machines or even often neglected in designing comminution circuits. In addition, other factors critical for comminution efficiency such as fracture energy, and particle fragmentation are rarely considered. The current study investigates the combined effects of particle textural properties and process operational conditions on the fragmentation of bed particle. In particular, the influence of ore texture and loading displacement rate (as the material and machine properties) on particle specific fracture energy, breakage mode, liberation, and frag-mentation was studied. The results indicate that ore textures with coarsest grain sizes and lower quantities of cleavage minerals have the least amount of fracture energy. In terms of fragmentation, a lower displacement rates results in higher quantities of the fragmented particles compared to the higher displacement rate. Among studied ore textures, two types of hematite ore textures which had the coarsest grain sizes had lower liberation in finer size fractions. Overall, the outcomes show that the displacement rate and ore texture can affect the specific fracture energy, particle fragmentation, mineral liberation, and breakage mode at different degrees.