Chalcopyrite Flotation Research Articles

A comparison of dry and wet grinding on gold-bearing sulphide ore flotation

This study investigates the hypothesis that dry grinding prior to flotation can mitigate the adverse effects of galvanic interactions, improve the selectivity of gold flotation compared to wet grinding, and offer additional benefits due to water scarcity concerns and high water treatment costs. The effects of dry and wet grinding on the flotation behavior of gold-bearing sulphide ore were studied comparatively in terms of flotation test results and pulp chemistry parameters (pH, Eh, and dissolved oxygen). In addition, flotation tests without conditioning were also conducted following dry grinding in an attempt to minimize water contact further. Results demonstrated that dry grinding increased pulp potentials and dissolved oxygen levels, implying more oxidative conditions. Despite a lower mass pull with dry grinding, flotation recoveries and grades of gold and chalcopyrite were comparable to wet grinding, while dry grinding enhanced pyrite flotation at the rougher stage. Notably, flotation without conditioning effectively rejected pyrite and achieved higher grades for gold and chalcopyrite, indicating selective flotation. Therefore, dry grinding before flotation emerges as a viable alternative for gold and chalcopyrite flotation due to its improved selectivity while carefully optimizing flotation strategies and reagents to maximize recoveries.

The application of KMnO4 in reverse flotation separation of chalcopyrite and talc and its selective depression mechanism

Talc exhibits excellent floatability and, as a major silicate gangue mineral associated with chalcopyrite, significantly obstructs the purification and smelting of chalcopyrite. This study investigates the reverse flotation separation of chalcopyrite and talc using KMnO4 as a depressant and DDA (dodecylamine) as a collector within a reverse flotation system. Single mineral flotation experiments show that after adding KMnO4, the recovery of chalcopyrite in 38–74 μm is only 6.86 %, whereas the recovery of talc in 45–106 μm and 25–45 μm are 93.47 % and 89.25 %, respectively. Further experiments with artificially mixed ores demonstrate that KMnO4 effectively achieves the separation of chalcopyrite and talc. The depression mechanism of KMnO4 on chalcopyrite and talc was analyzed using Zeta potential, contact angle measurement, AFM (atomic force microscopy), FTIR (Fourier transform infrared spectroscopy), XPS (X-ray photoelectron spectroscopy), and DFT (density functional theory) calculations. Mechanistic analysis indicates that in an alkaline environment, chalcopyrite can undergo a redox reaction with KMnO4, forming hydrophilic hydroxide species (Cu(OH)2, Fe(OH)3) on the chalcopyrite surface, which depresses chalcopyrite flotation. In contrast, the surface properties of talc are relatively stable and difficult to react with KMnO4, which cannot depress the flotation of talc. Therefore, KMnO4 can be used as an efficient and selective depressant for the reverse flotation separation of chalcopyrite and talc.

Statistical Evaluation of Flotation Behavior of Chalcopyrite in the Presence of SIPX and Acetoacetic Acid n-Octyl Ester as a Novel Collector Blend: A Sustainable Approach

The chalcopyrite deposit in Malanjkhand, India, is the largest copper ore producer in the country. However, its flotation performance has room for improvement. This study used standard flotation experiments using a mechanical flotation cell using a conventional collecting reagent and a collector blend consisting of xanthate and ester. A three-factor, three-level Box-Behnken design was used to statistically evaluate the experimental design. The obtained data were analyzed using an ANOVA, cubic plots, and response surface methods. The goal was to evaluate the effects and interactions of three key process parameters in chalcopyrite flotation: the dosages of sodium silicate (depressant), sodium isopropyl xanthate (collector), and acetoacetic acid n-Octyl ester (co-collector/modifier). The results implied that introducing acetoacetic acid n-Octyl ester along with minor tweaks in the dosages of sodium isopropyl xanthate helped increase copper grades by at least 15%, with good recovery percentiles. Among the three parameters tested, the copper’s grade and recovery were considerably positively influenced by the AoE dosage in the collector blend. Employing 0.006 kg/t sodium silicate and 0.0065 kg/t sodium isopropyl xanthate with 0.005 kg/t of acetoacetic acid n-Octyl ester, an optimum copper recovery of 88.87% could be achieved. However, with a sodium silicate dosage of 0.0048 kg/t, a SIPX dosage of 0.008 kg/t, and an AoE dosage of 0.005 kg/t, optimized copper grade (1.55%) could be achieved, which is a 78.1% increase from the feed sample grade. To validate the expected results, verification experiments were carried out, and the experimental findings were found to be on at par with the statistical model predictions. Furthermore, the calculated SPI value of 0.0000147cap Kg−1 for a global index per resident lies between 0 and 1.

Insight into the effect of ultrasonic treatment on surface properties and flotation behavior of chalcopyrite after galvanic corrosion of grinding media and chalcopyrite

Ultrasonic treatment is an effective means to promote chalcopyrite flotation. Chalcopyrite needs to be grinded before flotation production. During the grinding process, galvanic corrosion occurs between chalcopyrite and iron grinding media. Galvanic corrosion significantly affects the efficacy of ultrasonic treatment on chalcopyrite flotation. Nonetheless, there is still a lack of research on ultrasonic treatment of chalcopyrite after galvanic corrosion. In this study, micro-flotation tests, SEM-EDS, TOF-SIMS, XPS, ICP-OES and electrochemical tests were used to study the effects of ultrasonic treatment on the surface properties and flotation behavior of chalcopyrite before and after galvanic corrosion under different ultrasonic conditions and galvanic corrosion conditions. The results show that in the absence of galvanic corrosion, short time and low power ultrasonic treatment can improve chalcopyrite floatability. However, when the chalcopyrite after strong galvanic corrosion is subjected to ultrasonic treatment, the increase of galvanic corrosion temperature, galvanic corrosion time, ultrasound power and ultrasound time result in a marked reduction of the flotation recovery of chalcopyrite. The synergistic effect of ultrasonic and galvanic corrosion significantly inhibits the flotation recovery of chalcopyrite, which may provide a new potential way for the inhibition of sulfide ore in flotation production. The research results are helpful to expand the use range of ultrasonic processing for sulfide mineral pretreatment and flotation, and provide a theoretical reference for the application of ultrasonic treatment in sulfide minerals with galvanic corrosion.

The influence of NaCl on xanthate adsorption on chalcopyrite surface and chalcopyrite flotation

Due to freshwater scarcity, mineral flotation plants have been using alternative water resources including seawater together with water recycling resulting in the accumulation of salts in process water. However, how salts affect the adsorption of xanthates on the surfaces of sulphide minerals and subsequent sulphide mineral flotation is unclear. To address the knowledge gap, this study investigated how NaCl affected the adsorption of potassium amyl xanthate (PAX) on chalcopyrite surface and chalcopyrite flotation. Cyclic voltammetry (CV) tests identified that NaCl increased the oxidation of PAX and its adsorption on chalcopyrite surface due to elevated ionic strength and electrical conductivity of water, facilitating charge transfer among PAX, chalcopyrite surface and oxygen. NaCl also increased chalcopyrite surface oxidation to produce more CuS, facilitating the formation of copper-xanthate complexes. Flotation tests identified that the increased adsorption of PAX by NaCl was only translated into improved true flotation of chalcopyrite at a low PAX concentration such as 50 ppm in NaCl solutions with low and medium concentrations (0.1 and 0.7 M, respectively). At a high PAX concentration such as 150 ppm, the coexistence of high concentrations of PAX and NaCl led to strong froth destabilisation, resulting in a dramatic reduction in water recovery and true flotation recovery of chalcopyrite. The findings from this study will be able to guide the flotation plants to maximise mineral flotation by choosing collector dosage based on the ionic strength of process water.

A modified model based on CFD simulation and experiments of chalcopyrite flotation

The increasing attention to enhancing flotation performance in strong turbulent environment has become a focal point in research and practical applications. To predict turbulent flotation process, Computational Fluid Dynamics (CFD) simulations and flotation experiments were investigated on pure chalcopyrite in both smooth and vortex generator (VG) mineralized tubes. These investigations aimed to analyze flotation kinetics and flotation rate constant under conditions of 0.4–0.7 m3/h slurry flow rate and 0–45 μm, 45–75 μm, 75–125 μm, 125–180 μm particle classes. In the simulation, the user-defined functions (UDFs) and user-defined scalar (UDS) transport equations were used to model the collision, attachment and detachment of bubble-particle, thereby predicting the flotation rate constant. The results showed that the existing flotation kinetic model exhibited unsatisfactory prediction at various particle class and slurry flow rate. It was attributed to the insufficient consideration of turbulence in attachment model. Finally, a modified attachment model adopting a back-calculated method was proposed. This model predicted the flotation rate constant and its trends with changes in slurry flow rate, and the average prediction error is within 26 %. External validation of the model using pure mineral cassiterite demonstrated a prediction error of only 12 %.

Insights into flotation separation mechanism of chalcopyrite from galena using mercaptosuccinic acid as a novel depressant: Experimental and MDS studies

The separation of polymetallic sulfide ores by flotation is a difficult task in the mineral processing industry. In this investigation, a small-molecule organic compound, mercaptosuccinic acid (MSA), was used as a new depressant for inhibiting galena in chalcopyrite flotation. Micro-flotation and surface wettability tests indicated that MSA pronouncedly weakened the floatability of galena but not chalcopyrite, resulting in marked differences in their flotation recovery. Findings of Fourier transform infra-red (FT-IR) spectroscopy measurements and reagent adsorption trials showed that MSA was strongly adsorbed on galena, resulting in the inability of the collector to effectively interact with galena. Atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) analyses further corroborated that MSA showed a greater affinity for galena than chalcopyrite, this behavior markedly altered the superficial chemical environment of galena. Molecular dynamic simulations (MDS) showed that MSA increased the concentrations of H2O molecules on galena, which enhanced the surface hydrophilicity of galena.

Effects of biodegradable dispersants on the separation flotation of chalcopyrite and serpentine

The presence of serpentine slime coating on the chalcopyrite surfaces severely affects the chalcopyrite floatability. In this study, three biodegradable polymers, namely polyaspartic acid (PASP), polyepoxy succinic acid (PESA), and hydrolyzed polymaleic (HPMA) were used as dispersants to disperse the chalcopyrite and serpentine particles. The micro-flotation experiments demonstrated that the application of dispersants in the flotation effectively reduced the negative impact of serpentine over a wide pH range, restoring the recovery rate of chalcopyrite to about 85%. The XPS analysis revealed that the dispersants could be adsorbed onto the mineral surfaces through the binding of carboxyl groups with the magnesium or copper sites. As a result, the surface potentials of serpentine changed from positive to negative, while that of the chalcopyrite became even more negative, resulting in a strong electrostatic repulsion between them, which effectively eliminated the covering of the serpentine on the chalcopyrite surface. The AFM force measurements indicate a weak interaction of the polycarboxylic acids dispersants with the surface of chalcopyrite. Consequently, the adsorption of dispersants on the chalcopyrite surface has an insignificant impact on the subsequent adsorption of collectors, which is further supported by the adhesion force measurements between the air bubble and mineral surfaces. Therefore, the application of polycarboxylic acid dispersants in the flotation significantly enhanced the floatability of chalcopyrite in the presence of the serpentine fines.

The Effect of an Anionic Polyacrylamide on the Flotation of Chalcopyrite, Enargite, and Bornite

The Effect of an Anionic Polyacrylamide on the Flotation of Chalcopyrite, Enargite, and Bornite

Effect of low dissolved oxygen on chalcopyrite-molybdenite separation flotation at high altitude areas

Given the scarcity of conventional low-altitude high-quality copper–molybdenum resources, people gradually explore mining opportunities in elevated regions. Molybdenite in high-altitude ores is initially recovered with chalcopyrite, which is then separated and floated to produce refined molybdenite. There are few studies on the influence of the sulfide ore flotation process under high-altitude and low dissolved low-dissolved oxygen (DO) environments. In the present study, a flotation plant is designed and assembled to simulate the flotation of chalcopyrite at high altitudes by controlling the partial pressures of N2/O2 and DO under different altitude conditions, using the DO value as a standard. UV/VIS, electrochemical, and contact angle measurements were used to reveal the effect of conditions at 4600 m DO = 4.0 mg/L at altitude on chalcopyrite–molybdenite separation. Pure mineral flotation results indicate that a low DO environment at high altitudes favors the separation process and reduces the number of inhibitors. The mechanism of chalcopyrite inhibition at high altitudes still relies on the adsorption of large amounts of Fe(Ⅲ)-O/OH and hydrophilic polysulfides on the surface. Results reveal the reason for the relatively low inhibitor dosage in the chalcopyrite–molybdenite separation flotation process under low DO conditions at high altitudes. The findings also confirm that enhanced collector removal at high altitude altitudes is conducive to implementing a pathway toward a more efficient separation flotation process.

On the Use of Styrene-Based Nanoparticles to Mitigate the Effect of Montmorillonite in Copper Sulfide Recovery by Flotation.

Clay minerals have different negative effects on the froth flotation process such as low adsorption of collectors on valuable minerals, increased pulp viscosity, and the reduction in recovery and grade concentrates of copper sulfides. This study aims to evaluate the use of polystyrene-based nanoparticles (NPs) for the froth flotation of chalcopyrite and their ability to mitigate the negative effect of montmorillonite on the recovery of this sulfide. The experimental stage consisted of preparing a type of polystyrene-based nanoparticle (St-CTAB-VI), which was analyzed by dynamic night scattering (DLS) to establish its hydrodynamic size. Then, the effect of NPs on chalcopyrite's angle's in the presence and absence of montmorillonite (15%) was evaluated and compared with the contact angle achieved using potassium amyl xanthate (PAX) and a mixture of PAX and NPs. In addition, zeta potential measurements were carried out to investigate the interactions between the chalcopyrite and the montmorillonite or the NPs under fixed concentrations and microflotation tests were performed employing different times to evaluate the chalcopyrite recovery in the presence of montmorillonite, using NPs and mixtures with PAX. Finally, turbidity analysis as a function of time was performed to evaluate the occurrence of sedimentation and flocculation phenomena in suspensions of 15% montmorillonite in the presence and absence of chalcopyrite, nanoparticles, and mixtures of NPs and PAX. The results indicated that the mixture of NPs and PAX contributed to increasing the contact angle of chalcopyrite in the presence of montmorillonite. This can be associated with the presence of molecular and nanometric collectors that generated a higher hydrophobicity on the chalcopyrite particles, contributing to reducing the presence of clay minerals on the mineral surface. In addition, the mixture of NPs and PAX promoted the generation of nanoparticles on the sulfide mineral surface, which helps to detach the slime and facilitate the bubble/mineral attachment step during flotation.

Flotation separation of chalcopyrite from galena based on selective adsorption of pyrogallic acid: Experiments and MD simulations

Novel eco-friendly organic depressants with high selectivity are attracting ever-growing interests. The selective inhibition effect of pyrogallic acid (PA) on galena in chalcopyrite flotation was investigated in this study. Flotation trials showed that PA markedly depressed galena with only a small effect on chalcopyrite, which contributed to the separation of chalcopyrite and galena by flotation after adding a low dosage of PA. Surface hydrophobicity tests suggested that PA strongly adsorbed on galena but not on chalcopyrite, which attenuated the adsorption activity of collector on galena, thus rendering galena highly hydrophilic. Conversely, chalcopyrite still retained favorable floatability. These findings were corroborated by the results obtained from infrared and surface adsorption measurements. Results of time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy measurements also validated the strong adsorption of PA on galena. This behavior promoted the generation of other hydrophilic species on galena. In addition, molecular dynamic simulations demonstrated that PA tended to adsorb on galena, and water molecules accumulated on galena following PA adsorption, which would decrease the floatability of galena.

Application of organic phosphonic acid dispersant in the separation and flotation of chalcopyrite and serpentine

The floatation of target minerals is often severely deteriorated in highly muddy mineral flotation systems. In this study, it was shown that the chalcopyrite recovery was significantly decreased due to the slime-coating of the serpentine fines. To enhance the floatability of chalcopyrite in the presence of serpentines, two phosphonic acids of 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP) and ethylenediamine tetramethylene phosphonic acid (EDTMP) were applied as dispersants in the floatation process. The micro-flotation tests indicated that HEDP and EDTMP could well eliminate the adverse effect of coated serpentine on the floatability of chalcopyrite. Adsorption tests and X-ray photoelectron spectra (XPS) analysis demonstrated that HEDP and EDTMP could selectively adsorb on the serpentine surface due to the chelation of phosphonic acid groups with the magnesium atoms on the serpentine surface, which was confirmed by the flight secondary ion mass spectrometry (TOF-SIMS) characterization. The zeta potential measurements showed that the adsorption of dispersants on serpentine changed the surface charges from positive to negative, while the zeta potential of chalcopyrite became more negative due to the dissolution of copper and iron cations from the chalcopyrite surface. Therefore, the electrostatic repulsion effectively prevented the slime-coating of serpentine on the chalcopyrite surface, which was also supported by the atomic force microscope (AFM) force measurements. As a result, the use of dispersants eliminated the adverse effects of serpentinite and greatly improved the floatability of chalcopyrite. The findings in this work indicate that the phosphonic acids of HEDP and EDTMP might find their application as effective dispersants to improve the floatability of target minerals in highly muddy mineral flotation systems.

A non-inhibitor flotation process for selective enrichment of chalcopyrite from molybdenite by using 5-methyl diethyl dithiocarbamate-1,3,4-oxadiazole-2-thione

During froth flotation, the separation of chalcopyrite from molybdenite is hindered by their similar surface properties. Therefore, it is imperative to develop an efficient selective collector with innovative minerophilic groups and reduce the use of inhibitors. In this study, 5-methyl diethyl dithiocarbamate-1,3,4-oxadiazole-2-thione (MDCODT) was first introduced as a collector in chalcopyrite flotation separation from molybdenite. Micro-flotation experiment results expressed that the selectively separation of chalcopyrite from molybdenite could be realized without the addition of inhibitor. Wettability tests, ζ-potential analyses and UV spectrum demonstrated that MDCODT specifically adsorbed on the surface of chalcopyrite rather than molybdenite. And the adsorption mechanism was future explored by AFM scan, electrochemical tests, FTIR spectrum, XPS spectrum and DFT calculation. The active centers of MDCODT are concentrated in dithiocarbamate and oxadiazole thione groups, and MDCODT-Cu(I) complexes can be covered on the chalcopyrite surface with formation of Cu-S and Cu-N bonds. The di-minerophilic group oxadiazole-thione collector, MDCODT, exhibits the advantages of cost-effectiveness and environmental friendliness, rendering it suitable for a wide range of industrial applications.

A case study on the recovery of unevenly embedded particle size in high-carbon chalcopyrite using an alkyne-based thioester collector: Flotation processing and adsorption mechanism

The difference in chalcopyrite's primary ore-hosting rocks (dolomite and carbonaceous slate) in the Democratic Republic of the Congo results in an extremely uneven grain size distribution. Additionally, the presence of 2.21% organic carbon in the gangue impacts flotation efficiency. To address these challenges, ore properties were analyzed using the Mineral Liberation Analyzer (MLA), X-Ray Diffractometer (XRD), and microscopy. Flotation process was modified to incorporate a "middlings regrinding" processing, utilizing PDEC (an alkyne-based thioester collector, prop-2-yn-1-yl diethylcarbamodithioate) as the collector for experimental studies. Density Functional Theory (DFT) calculations elucidated the interaction mechanism of PDEC on chalcopyrite's surface. The MLA analysis indicates that chalcopyrite is mainly found in medium to fine grains, with the presence of fine-grained copper minerals smaller than 0.04mm accounting for 16.29% of the sample. This implies that these minerals require fine grinding for effective separation. Despite interference from organic carbon, PDEC demonstrates remarkable selectivity and efficiency in chalcopyrite flotation. By employing the "middlings regrinding" flotation method, a concentrate with a Cu content of 26.79% and a recovery of 87.88% was achieved, representing an increase of 0.17% in Cu grade and 4.09% in recovery rate compared to the conventional flotation process. DFT analysis demonstrates that the S 3p orbitals in carbon-sulfur double bond of PDEC and the C 2p orbitals in its acetylene group significantly affect its collection efficiency, engaging in hybridization with the Fe 3d orbitals on the surface of chalcopyrite, thereby facilitating a robust bonding interaction.

Identifying true collectorless flotation of chalcopyrite in calcium chloride solutions

Given the increasing use of seawater containing primary ions (e.g. Na+ and Cl-) and secondary ions (e.g. Ca2+ and Mg2+) in flotation plants to counteract the global freshwater scarcity, more and more studies have been performed to determine the impacts of seawater on mineral flotation behaviors. From a new and practical niche, this study aimed to determine the natural floatability of chalcopyrite in the presence of Ca2+ as a secondary ion by considering the alterations of surface hydrophobicity from both the aspects of surface oxidation and metal ion precipitation. Through true collectorless flotation, Cyclic Voltammetry analyses, calcium speciation and Cryogenic X-ray Photoelectron Spectroscopy measurements, this study identified that the true flotation recovery of chalcopyrite was much lower in CaCl2 solutions than in NaCl solutions even with the same ionic strengths. While the presence of NaCl enhanced chalcopyrite surface oxidation to produce hydrophobic and hydrophilic products, the presence of CaCl2 inhibited chalcopyrite surface oxidation through the formation of CaCO3 precipitate which not only served as a passive layer but also being hydrophilic itself. As a result, the surface hydrophobicity on chalcopyrite was determined by the amount of oxidation products in NaCl solutions, but it was determined by the amount of CaCO3 precipitate in CaCl2 solutions. Despite the larger amount of CaCO3 precipitate in CaCl2 solutions with ionic strengths of 0.7 and 1.2 M, compared to deionized water and CaCl2 solution with an ionic strength of 0.1, the true flotation recovery of chalcopyrite was higher. This was attributed to much smaller air bubbles generated in CaCl2 solutions with high ionic strengths of 0.7 and 1.2 M, promoting bubble-particle collision and hence the true flotation of chalcopyrite.

Flotation separation of chalcopyrite from pyrite and sphalerite using a novel collector: An experimental and mechanism investigation

In this paper, a new collector, named O-isobutyl-N-allyl thionocarbamate (IBATC), was synthesized, and the structure was characterized by Fourier Transform Infrared Spectrometer (FTIR) and 1H NMR, 13C NMR analysis. The collection performance of IBATC was evaluated by flotation tests and interaction mechanism was investigated by means of adsorption amount, zeta potential measurements, FTIR, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculation. The flotation tests results proved that IBATC was inclined to collect chalcopyrite compared with pyrite and sphalerite. Especially in the pH range of 9.5–10 and IBATC concentrate of 30–40 mg/L, the recovery of chalcopyrite exhibited more than 80 %. The adsorption amount and zeta potential measurements showed that IBATC had a greater orientation to chalcopyrite. FTIR and XPS analysis demonstrated IBATC chemically adsorbed on chalcopyrite surface, whereas physically adsorbed on pyrite and sphalerite. Further, DFT calculation of the interaction between IBATC and chalcopyrite proved that S atom of IBATC donated electrons to Cu sites on chalcopyrite surface and the adsorption energy was −19.45 kcal/mol, referring to an exothermic reaction. As a result, IBATC showed great capacity for the separation flotation of chalcopyrite, pyrite and sphalerite.

CFD investigation of chalcopyrite flotation prediction coupled with flotation kinetic model

CFD (computational fluid dynamics) simulation plays an important role in flotation prediction research and application. The flotation process of chalcopyrite in a three-dimensional mineralized tube was simulated coupled with flotation kinetic model. Regarding kinetic prediction model in the flotation process is explored at gas flow rate of 0.06 m3/h, slurry flow rate of 0.4 and 0.5 m3/h, including collision probability model, attachment probability model, detachment probability model and bubble slip velocity model. Flotation experiments of chalcopyrite is performed, and the simulation of flotation process is realized by adding UDF (user-defined function). Furthermore, the flotation rate constant is taken to verify the validity of the model. The prediction error of flotation rate constant is 19 % and 17 % between flotation experiments and simulations at slurry flow rate of 0.4 and 0.5 m3/h, respectively. According to the combinations of flotation kinetic model, it’s found that the prediction results of Yoon-Luttrell collision probability model, Yoon-Luttrell attachment probability model, Schulze detachment probability model and Kostoglou bubble slip velocity model are superior to other combinations. the prediction error of flotation rate constant is 8 % at the slurry flow rate of 0.4 m3/h.

Understanding the Effects of Hydrophobic Particle Densities on Bubble-Liquid Motion and Gangue Entrainment in the RFC’s Reverse Fluidized Bed Through CFD Simulation

ABSTRACT The Reflux Flotation Cell (RFC) developed recently provides great potential in solving the emerging challenges, in terms of low plant capacity and low metal production, faced by the resources industry. However, the bubble-liquid motion and the mechanisms responsible for gangue entrainment in the RFC have not been well studied. In this study, chalcopyrite and coal were chosen as value materials and quartz was chosen as a gangue material, and the flotation of chalcopyrite or coal against quartz was conducted in the RFC. It was found that chalcopyrite flotation produced a much higher quartz recovery than coal flotation despite the same operating conditions employed, which indicated a great effect of hydrophobic particle density on gangue entrainment in the RFC. CFD simulations indicated that a higher density of hydrophobic particles increased the gas holdup in the RFC’s reverse fluidized bed and the boundary of the air phase, which promoted gangue entrainment. Meanwhile, the higher density of hydrophobic particles also inhibited the formation of a liquid recirculation loop in the reverse fluidized bed, weakening the displacement of gangue particles with wash water and resulting in higher gangue entrainment. The findings from this study will provide guidance on how to minimize gangue entrainment in chalcopyrite flotation in the RFC.

Water-bridged self-assembly of low-odor xanthate surfactant for selective flotation of chalcopyrite

Xanthate, a high-consumption functional surfactant, poses health and environmental risks due to the presence of volatile sulfides and pungent odors. In this study, we designed a novel ether group enhanced xanthate collector, O-(2-(tert-butoxy)ethyl) xanthate (TBOEX), which exhibits low odor and excellent flotation performance. The high matching between the calculated and the experimental infrared spectrum confirms the existence of water-bridged self-assembly behaviour. Odor evaluation results show that TBOEX reduced the content of volatile sulfur organic compounds and volatile hydrocarbons by 54.2% and 88.6%, respectively, compared to isobutyl xanthate (IBX), effectively reducing odor production. Flotation experiments and Zeta potential measurements demonstrate that TBOEX adsorbs densely on the surface of chalcopyrite, while the rich hydroxide on the surface of pyrite hinders the self-assembly of the collector, resulting in good selectivity for chalcopyrite. DFT calculations further reveal that TBOEX can form a stable and tightly arranged adsorption layer bridged by water molecules on the surface of chalcopyrite through two paths, and interact with d orbitals of copper atoms in the form of Cu-S tetrahedra through π* orbitals, finally improving the flotation recovery of chalcopyrite. The discovery of the water-bridge self-assembly mechanism and interfacial adsorption behavior of TBOEX is expected to drive the targeted design of collectors.