Flotation Performance Research Articles

Adsorption process and mechanisms of AEO-3/dodecane mixed collector on low-rank coal surface driven by water flow: A non-equilibrium molecular dynamics simulation study

During coal slime flotation, the collector is adsorbed to the coal in the form of fine oil droplets in the turbulent slurry. And understanding the adsorption behavior of collector oil droplets on the coal surface is important for the development of efficient collector. In this study, the adsorption process and mechanism of triethylene glycol dodecyl ether (AEO-311triethylene glycol dodecyl ether.)/dodecane mixed collector oil droplet (MCOD22mixed collector oil droplet.) on the surface of low-rank coal driven by water flow were investigated by non-equilibrium molecular dynamics simulations. The changes of the mass center velocity of MCOD, contact area and interaction energy between MCOD and coal during the simulation were analyzed, and the adsorption process was divided into the adhesion stage, spreading stage and equilibrium stage. The kinetic reason for the adsorption of AEO-3 molecules at the interface was found. The pushing of oil droplet by the water flow caused the AEO-3 molecules to be slowly pressed into the contact interface between the oil droplet and coal, and the adsorption occurred. The presence of polar oxygen-containing functional groups on the AEO-3 molecule makes it much more strongly adsorbed on low-rank coal than dodecane. Water molecules play an important role in the adsorption process of AEO-3 with coal, and the bridging action of water molecules that enables indirect adsorption of collector with coal was proposed. The water molecule connects AEO-3 and coal molecules, which cannot form hydrogen bond due to the distance, through hydrogen bonding, and inserts between alcohol oxygen, ether oxygen and carbonyl oxygen, which are originally mutually exclusive, so that the three of them (OAEO-3, H2O and Ocoal) are connected together through hydrogen bonding (OAEO-3…H-O-H…Ocoal), and the stability of AEO-3 adsorption on coal surface is greatly enhanced. The presence of strong indirect electrostatic interactions between polar collector and coal generated by the bridging action of water molecules proves that it is the strong electrostatic interactions that are the reason for the strong flotation performance of polar collector on low-rank/oxidized coals.

Effect of ferric ions on surface sulfidization of hemimorphite and implications for xanthate adsorption

• Addition of Fe 3+ weakened the surface activity of hemimorphite. • The sulfidization of hemimorphite was depressed in the presence of Fe 3+ . • Adsorption of xanthate on hemimorphite surfaces was hindered by Fe 3+ . The existence of ferric ions (Fe 3+ ) in the pulp solution will severely affect the surface properties and flotation performance of targeted minerals, so its specific effect on the interaction of flotation reagents with the mineral surface must be understood. In this work, the effect of Fe 3+ on the surface sulfidization of hemimorphite was investigated, and the interaction mechanism of Fe 3+ with the hemimorphite surface was clarified. The results of time-of-flight secondary-ion mass spectrometry and X-ray photoelectron spectroscopy indicated that the addition of Fe 3+ before sulfidization generated Fe–OOH species and hindered the formation of active sulfide species on hemimorphite particles. Infrared spectroscopy and contact-angle measurements showed that the addition of Fe 3+ was detrimental to the adsorption of xanthate species on hemimorphite particles, prohibiting the formation of hydrophobic hemimorphite surfaces in the Fe 3+ –sulfidization–xanthate system. Thus, the presence of Fe 3+ in the pulp of hemimorphite was not conducive to the formation of the desired sulfidization products and stable adsorption layers of xanthate on its surface, resulting in unsatisfactory floatability of zinc oxide minerals containing hemimorphite.

Impact of flotation operational parameters on the optimization of fine and coarse Itabirite iron ore beneficiation

This paper investigates the impact of operational parameters on the reverse flotation of Timbopeba itabirite iron ore in a pneumatic (MBE Pneuflot) flotation cell. To this end, the effects of physical and chemical parameters (i.e., collector and depressant dosage, superficial gas velocity (Jg), solids concentration, and feed rate) on the reverse flotation of iron ore are investigated in detail. Results show that increasing collector dosage increases quartz recovery, particularly for the coarser quartz where recovery increases by nearly 30%. Increasing depressant dosage results in a decrease in both quartz recovery and hematite loss, for the coarser hematite particles. In addition, increasing the feed rate does not affect quartz recovery or hematite loss, suggesting that the pneumatic flotation cell is not constrained by residence time. Furthermore, increasing the superficial gas velocity results in an increases in quartz recovery to an optimum at a Jg of around 0.6 cm/s after which it decreases significantly, particularly for the coarser particles where recovery decreases by 50%. Decreasing the solids concentration does not affect quartz recovery but results in a significant reduction in hematite loss. Here, fine and coarse hematite loss decrease from around 25% to 12% and 10% to 2%, respectively. Solids concentration and Jg are operating parameters that have the largest effect on the flotation performance of the pneumatic flotation cell. Overall, the obtained results suggest that this flotation cell should be operated at relatively low superficial gas velocities and solids concentrations. However, these findings are for a pilot scale and would need to be examined at larger scale (e.g., an industrial scale) where different operating conditions may be optimal.

An Assessment of the Role of Combined Bulk Micro- and Nano-Bubbles in Quartz Flotation

Bulk micro-nano-bubbles (BMNBs) have been proven to be effective at improving the flotation recovery and kinetics of fine-grained minerals. However, there is currently no research reported on the correlation between the properties of BMNBs and flotation performance. For this purpose, aqueous dispersions with diverse properties were created by altering preparation time (0, 1, 2, 3, 5, and 7 min), aeration rate (0, 0.5, 1, 1.5, and 2 L/min) and aging time (0, 0.5, 1, and >3 min). Micro- and nano-bubbles were characterized using focused beam reflection measurements (FBRM) and nanoparticle tracking analysis (NTA), respectively. The micro-flotation of quartz particles was performed using an XFG-cell in the presence and absence of BMNBs with Cetyltrimethylammonium bromide (CTAB) as a collector. The characterization of bubble sizes showed that the bulk micro-bubble (BMB) and bulk nanobubble (BNB) diameters ranged from 1–10 μm and 50–400 nm, respectively. It was found that the preparation parameters and aging time considerably affected the number of generated bubbles. When BNBs and BMBs coexisted, the recovery of fine quartz particles significantly improved (about 7%), while in the presence of only BNBs the promotion of flotation recovery was not significant (2%). This was mainly related to the aggregate via bridging, which was an advantage for quartz flotation. In comparison, no aggregates were detected when only nano-bubbles were present in the bulk solution.

A novel collector for high-sulfur bauxite flotation desulfurization

ABSTRACT Effective desulfurization of high-sulfur bauxite is one of the major problems in the alumina production industry. To overcome this, a novel nanoparticle collector (NC) to improve the desulfurization performance during flotation process was synthesized via emulsion polymerization method, whereby lignin (natural polymer) was used as the host monomer. The NC’s syntheses, desulfurization performance, characterization tests, and adsorption on pyrite were studied. Results showed that the optimum conditions for the syntheses of NC (average particle size of 252.5 nm) were at mass ratio of lignin (host monomer), potassium butyl xanthate (functional group) and sodium dodecyl sulfate (emulsifier) of 1:20:2, and reaction temperature of 70°C. NC showed better flotation performance (maximum desulfurization), and shorter flowsheet, compared to common collectors. On a different note, tests suggested that NCs were uniformly adsorbed on the surface of pyrite via physico-chemical way.

A Quantitative Relationship between Oxidation Index and Chalcopyrite Flotation Recovery

The surface oxidation of chalcopyrite is one of the most important factors affecting its flotation performance. In this study, a critical oxidation degree is proposed to define “slight” and “significant” oxidation in terms of surface species and chalcopyrite flotation recovery. Slight oxidation enhanced chalcopyrite hydrophobicity, but significant oxidation reduced its recovery apparently. Microthermokinetic measurements indicated that the apparent activation energy (Ea) of chalcopyrite oxidation was reduced from around 173 kJ·mol−1 to 163 kJ·mol−1 when the reaction changed from slight oxidation to significant oxidation when applying H2O2. The surface oxidation degree was defined as the ratio of hydrophilic species to hydrophobic species. The highest recovery (94.8%) and contact angle (93°) were achieved at a concentration of 0.1 vol.% H2O2, with the lowest oxidation degree of 0.388 being observed. The oxidation degree was correlated to the flotation recovery, with a quantitative relationship (y = −298.81x + 213.05, y and x represent flotation recovery and oxidation degree, respectively, 0.388 ≤ x ≤ 0.618) being established, thereby giving a guideline to better manage chalcopyrite flotation by controlling its surface oxidation and SBX adsorption on chalcopyrite surfaces.

Combined effect of operating variables on performance and kinetic of lead flotation

ABSTRACT This study aims to investigate the effects of pH and chemical reagents to model and optimize the flotation process of a complex lead ore containing 2.44 wt% Pb. For this purpose, the effects of pulp pH, collectors (PAX and R404), depressant (FeSo4), and activator (Na2S) concentrations were studied using response surface methodology. Furthermore, the influence of these parameters was studied on flotation kinetics parameters. The optimization studies indicated that the desired Pb recovery (84.1%) and grade (26.6%) was obtained from the test, which was performed with the optimum flotation conditions: 75 g/t PAX, 80 g/t FeSo4, 735 g/t Na2S, 20 g/t R404 and pH 9.5. The results of statistical analyses showed that the pulp pH, PAX concentration, and interactions between pH-R404 concentration and PAX concentration-R404 concentration were the most influential parameters on concentrate grade and recovery. From the kinetic studies, it was observed that the flotation rate coefficient and ultimate recovery were strongly dependent on the pulp pH. The flotation rate coefficient increased with enhancing the pH from 8 to 9.5 and after that reduced with increasing the pH to 11.

Investigation of collector mixtures on the flotation dynamics of low-rank coal

Here, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), flotation experiments, and low-rank coal (LRC) particle-bubble attachment measurements (using the particle-bubble attachment index [PBAI]) were employed to explore the effects of collector mixtures on the flotation kinetics of LRC particles. At a flotation dosage of 3.0 kg/t, the greatest flotation recovery (62.51%) for a single collector was achieved using triethanolamine oleic acid monoester (TOAM), compared with using kerosene or 2-ethylhexanol. At the same dosage, the maximum flotation recovery increased to 84.25% when using a mixture of TOAM with kerosene. However, when the collector dosage was more than 2.5 kg/t, the fitting result of the flotation rate constant obtained by mixing TOAM with kerosene was larger than those obtained by mixing 2-ethylhexanol with either kerosene or TOAM. Furthermore, when the attachment time exceeded 100 ms, the greatest PBAI value (0.84) was obtained when mixing kerosene with TOAM, rather than when mixing 2-ethylhexanol with kerosene or TOAM. Thus, this study presented an improved mixture of TOAM and kerosene that can aid the flotation performance of LRC and could be regarded as potential application for LRC flotation industrial.

Microbubble-microplastic interactions in batch air flotation

Presence of microplastics in waste streams and the environment is a challenge of much recent concern. Bubbles are used for solid–liquid separation in froth flotation and dissolved air flotation (DAF). Bubble-particle interactions are key for understanding flotation removal efficiency of particulates. Limited studies provide in-situ characterization of particle size distribution, shape and concentration before and after flotation. The use of microbubbles to specifically remove microplastics has not been extensively investigated. This study presents a batch flotation method to assess the removal of spherical polyethylene (PE) and non-spherical PE, polypropylene (PP), polyvinyl chloride (PVC), and polymethyl methacrylate (PMMA) microplastic of different densities at 10–600 µm size range with 50–110 µm sized microbubbles. In-situ image analysis allowed measuring particle shape, size and concentration in solution prior to and after flotation as well as capturing particle-bubble interactions at the micro-scale. Besides determining flotation performance for different microplastic sizes, shapes and types, the effect of surfactant concentration and ionic strength was investigated and discussed in relation to particle collection efficiency. This study provides important quantitative results on bubble-particle interaction that allow selective removal of microplastic from solution and presents a straightforward direct in-situ visualization method for tracking and characterizing micrometer-sized particles in solid–liquid-gas multiphase media.

Effect of deep oxidation of chalcopyrite on surface properties and flotation performance

In this study, chalcopyrite was oxidized in hydrogen peroxide (H 2 O 2 ) solutions of different concentrations to simulate different degrees of oxidation in real ores, and the effects of H 2 O 2 treatment on chalcopyrite surface properties and flotation performance were investigated by surface analysis techniques and floatation experiments, which implied the reason for the poor grade and recovery of oxidized chalcopyrite concentrate in the production process of the ore. Flotation results showed that when the concentration of H 2 O 2 increased from 0% (by weight) to 5%, the flotation recovery of chalcopyrite decreased sharply. However, with increasing H 2 O 2 concentration from 5% to 30%, chalcopyrite recovery improved relatively to different degrees with different collector concentrations. Analyses of X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma-atomic optical emission spectrophotometry (ICP-OES) results indicated that the pretreatment with H 2 O 2 caused that hydrophilic substance formed on chalcopyrite surface with the dissolution of copper ions, and the dissolution amount of copper increased with the increase of H 2 O 2 concentration. UV–visible spectrophotometer and Fourier Transform Infrared spectrum (FTIR) studies indicated that the pretreatment of chalcopyrite with H 2 O 2 had little effect on the adsorption amount of potassium butyl xanthate (PBX) on chalcopyrite surface. However, due to the dissolution of copper ions, PBX interacted with chalcopyrite mainly as buthyl dixanthogen (BX) 2 .

Sodium N-Lauroylsarcosinate (SNLS) as a Selective Collector for Calcareous Phosphate Beneficiation

Sodium N-lauroylsarcosinate (SNLS) was employed as a selective flotation collector for dolomite–apatite separation. The influence of pH, condition time, and collector dose on the flotation performance of both apatite and dolomite minerals was investigated using single mineral and binary mixed mineral flotation experiments. The performance of SNLS was compared to sodium oleate (NaOL), as a standard collector. In this study, the adsorption mechanism of SNLS on both minerals was studied using zeta-potential and FT-IR measurements. The results showed that SNLS prefers to adsorb on the dolomite mineral. The maximum difference in floatability was 83% for single dolomite and apatite minerals at pH 10 in the presence of 0.05 mmol/L SNLS. Binary mixtures of dolomite and apatite minerals of different ratios were applied, to evaluate their separation efficiency. The SNLS could separate dolomite from its mixtures with apatite minerals. Using 0.2 mmol/L of SNLS at pH 10, a concentrate of 30.9% P2O5 and 0.79% MgO was obtained from a natural phosphate ore having 25.8% P2O5 and 5.16% MgO.

Uncovering the flotation performance and adsorption mechanism of a multifunctional thiocarbamate collector on malachite

In this paper, a novel collector N-octanoyl-S-carboxyethyl thiocarbamate (OCETC) containing CO, CS and -COOH groups was synthesized and applied to recover malachite. The flotation performance and adsorption mechanism of OCETC on malachite surface were systematically investigated by DFT calculation, zeta potential, FTIR, XPS, contact angle measurements and flotation experiments. It was found that CO, CS and -COOH groups were the functional sites which could react with Cu(II) ions on malachite surface and formed COCu(I) and CSCu(I) bonds. The adsorption of OCETC on malachite surface significantly improved its surface hydrophobicity since the contact angle of water on malachite changed from 46.5° to 78.0°. The flotation experiments demonstrated that 6 × 10−5 mol/L OCETC enabled the recovery of up to 98.24% malachite at pH 8.0. Under the same flotation conditions, OCETC exhibited comparable flotation recovery for malachite compared to octyl hydroxamic acid (98.43%), but much better than that by benzoyl hydroxamic acid (54.13%).

Behavior and Mechanism of a Novel Hydrophobic Collector in the Flotation of Bastnaesite

In order to improve the recovery of rare earth elements, finding a collector with a strong selectivity ability had become the focus of research. In this paper, phenylpropyl hydroxamic acid (PHA) was used as a new hydrophobic surfactant collector for the separation of bastnaesite from calcite, and salicylic hydroxamic acid (SHA) was used as a reference collector. The results of a single mineral flotation test with SHA show that the reagent has good collection performance and selectivity. In addition, Zeta potential measurements and FTIR analysis show that PHA is adsorbed on the surface of bastnaesite by chemical adsorption, and the surface state of bastnaesite changes after PHA treatment. By XPS analysis, PHA interacts with Ce, and forms a Ce–O bond with Ce. It is speculated that the hydroxamic acid forms a five-element-chelated hydroxamic group with Ce on bastnaesite surface, so as to improve the hydrophobicity of bastnaesite, and make bastnaesite float more easily out of the pulp. According to DFT calculation, PHA has better adsorption capacity and stronger hydrophobicity than SHA, and shows superior electronic group capacity and chemical reactions that promote its flotation performance.

Investigation of Internal Classification in Coarse Particle Flotation of Chalcopyrite Using the CoarseAIRTM

This work introduces the CoarseAIR™, a novel system utilizing a three-phase fluidized bed and a system of inclined channels to facilitate coarse particle flotation and internal size classification. Internal classification in the CoarseAIR™ was investigated in a series of continuous steady-state experiments at different inclined channel spacings. For each experimental series, a low-grade chalcopyrite ore was milled to a top size of 0.53 mm and methodically prepared to generate a consistent feed. The air rate to the system was adjusted to determine the impact of the gas flux on coarse particle flotation and overall system performance, with a focus on maximizing both copper recovery and coarse gangue rejection. A new feed preparation protocol led to low variability in the state of the feed, and in turn strong closure in the material balance. Hence, clear conclusions were drawn due to the high-quality datasets. Inclined channel spacings of z = 6 and z = 9 mm were used. The z = 9 mm spacing produced more favourable copper recovery and gangue rejection. Higher gas fluxes of 0.30 to 0.45 cm/s had a measurable, adverse effect on the recovery of the coarser hydrophobic particles, while the gas flux of 0.15 cm/s delivered the best performance. Here, the cumulative recovery was 90%, and mass rejection was 60% at 0.50 mm, while the +0.090 mm recovery was 83% with a gangue rejection of 85%. The system displayed robust performance across all conditions investigated.

Is it possible to efficiently and sustainably remove microplastics from sediments using froth flotation?

Microplastics (MPs) contamination in sediments is becoming an intractable environmental issue. Numerous methods are proposed for removing microplastics from aqueous solution, however, the techniques developed for microplastic removal from sediments have been rarely reported. To target the dilemma, this work innovatively applied froth flotation to the MPs removal from beach and lake sediments. Interestingly, we found that the sediment particle adhered to the MPs surfaces resulted in unavailable attachment of air bubbles to MPs surfaces. The effects of pH, salinity, moisture, MPs property, sediment type, and incubation time on MPs flotation were systematically investigated. According to characterization, polyvinyl chloride (PVC) was only covered by aluminosilicate, while acrylonitrile butadiene styrene (ABS) interacted with aluminosilicate and quartz. Analysis of Extended Derjaguin Landau Verwey Overbeek (EDLVO) further confirmed that the stronger electrostatic repulsion between PVC and sediment contributed to the higher energy barrier. However, sediment particles were easier to adhere to ABS with less negative surface potential. Besides, metal ions adsorbed on MPs surfaces might serve as a bridge to link MPs and sediment particles. To improve the flotation performance, a flotation process combined 10 g/ton of sodium oleate could achieve approximately 100% removal of MPs. To further evaluate the applicability of froth flotation, we conducted life cycle assessment (LCA) and economic assessment. Froth flotation outperformed other separation methods in all environment categories. The cost of froth flotation, mostly electricity, was much lower than other removal technologies. Overall, this work provided an effective and sustainable candidate for MPs removal from the sediment environment.

The effect of molecular structure on the properties of cationic polyacrylate and its flocculation‐flotation performance of oilfield oily wastewater treatment

AbstractWith the increasing amount of oily wastewater produced in the offshore oilfield, more efficient air flotation agent is needed to be developed. Cationic polyacrylate with amphiphilic structure has been found to be a type of potential efficient air flotation agent. However, the effect of molecular structure on its properties and performance was lack of research. In this paper, copolymers with tertiary amine as side group were synthesized by copolymerization of ethyl acrylate (EA) and tertiary amine monomers, and then a series of cationic polyacrylates were prepared by quaternization of tertiary amine with quaternization reagent. The effects of tertiary amine monomer type (including dimethylaminopropyl methacrylamide (DPM) and dimethylaminoethyl methacrylate (DEM)), quaternization reagent type (including 3‐Chloro‐1,2‐Propanediol and 3‐chloro‐2‐hydroxytrimethylammonium chloride) and quaternization degree on the cationic polyacrylate properties and its flotation performance were investigated. The experimental results showed that the flotation performance increased with the increasing hydrophilicity and cation degree of the hydrophilic unit in the cationic polyacrylate. When the tertiary amine monomer was DPM, quaternization reagent was 3‐chloro‐2‐hydroxytrimethylammonium chloride, and theoretical quaternization degree was 100%, the oil removal of product PE‐M‐1.0 was the highest. When PE‐M‐1.0 dosage was 50 mg/L, gas flow was 1 L/min, flotation time was 10 min, its oil removal rate was higher than 95% in the range of 20‑60°C. The results of zeta potential measurement and microfluidic experiment showed that PE‐M‐1.0 can increase the size of oil droplets by destroying the electric double layer on the surface of oil droplets and maintain the stability of bubbles, which was helpful for the improve of gas bubble‐oil droplet collision probability and adhesion efficiency.

Influence of calcium and ferric ions on the depression of chalcopyrite by CMC: Flotation performance and adsorption mechanism study

The inevitable presence of metal ions in the slurry significantly impacts the adsorption of organic depressants. In this study, the influence of Fe3+ and Ca2+ on the depression of chalcopyrite by carboxymethyl cellulose (CMC) was investigated. CMC slightly depressed chalcopyrite flotation, and the addition of Ca2+ hardly impact its depression effect. However, the pre-treatment with Fe3+ enhanced its depression effect severely at acid conditions, while this hydrophilic strengthening effect gradually disappeared under alkaline conditions. CMC physically attached to blank chalcopyrite surface, the surface modification with FeCl3 not only increased its adsorption capacity on chalcopyrite surface but also altered it from physical adsorption to chemical adsorption. Cu and Fe sites were not involved in CMC adsorption on blank chalcopyrite surface, and the strongly electrostatic repulsion hindered its adhesion under alkaline conditions. After surface modification with FeCl3, electrostatic repulsion was weakened, and Fe sites participated in the bonding with CMC molecule. Thus, chalcopyrite was strongly depressed. However, the contents of Fe3+, Fe(OH)2+ and Fe(OH)2+ on modified chalcopyrite were much less at strong alkaline conditions than acid conditions, which not favored CMC attachment.

Awaruite (Ni3Fe), a new large nickel resource: Electrochemical characterization and surface composition under flotation-related conditions

Awaruite is a native nickel–iron alloy (Ni3Fe), found in serpentinized ultramafic rocks, that has gained interest as a possible source of nickel. FPX Nickel is advancing a very large awaruite deposit in central British Columbia, Canada, on which this work is based. To date there is limited information available regarding the flotation conditions to selectively concentrate awaruite from gangue minerals in serpentinite ores. The aim of this work was to investigate the floatability of awaruite in different solution conditions with a xanthate collector. Awaruite readily floated in acidic solution with a xanthate collector but not in neutral and alkaline solutions. Voltammograms on awaruite indicated that the alloy shows an active passive transition behaviour in acidic solution and passive behaviour in neutral and alkaline solutions. The passivation layer formed in neutral and alkaline solutions showed to inhibit the interaction between xanthate and awaruite surface. Infrared spectra on awaruite showed the presence of xanthate compounds attached to the surface in acidic condition at potentials higher than the reversible potential of xanthate/dixanthogen. Based on experimental results, it was postulated that xanthate chemisorbs on awaruite and then it oxidizes to form dixanthogen. Also, it was demonstrated that when passivated, awaruite quickly activates in acidic solution, good flotation performance was achieved with 10 min of conditioning, and similar performance was obtained after 30 min of conditioning. This work serves as a confirmation that is possible to float awaruite using xanthate, a well-known collector that offers selectivity over oxides and silicate minerals, which are the main gangue minerals in serpentinite ores.

Investigation on the correlation between ferrous ion and the floatability of pyrite with different oxidation degrees

This work aims to establish the quantitative relationship between the surface oxidation state of pyrite and flotation performance. In this paper, an efficient method was proposed to prepare pyrite with different oxidation degrees. Flotation tests show that the floatability of pyrite decreased with prolonging the oxidation time. Tof-SIMS results reveal that the main component on the oxidized pyrite surface is Fe hydroxides or oxides. XPS analysis confirms that Fe(OH)2 and FeOOH are the main formula of Fe species, and the ratio of Fe2+/Total Fe agrees well with the floatability of pyrite with different oxidation degrees, which can be taken as an index to develop the flotation performance of pyrite. DFT simulation calculation further demonstrates the reliability of Fe(OH)2 as the active site. This study provides essential surface chemistry evidence for correlating the surface species with the floatability of pyrite with different oxidation states through quantitative analysis of various intermediate products.

Molecular Dynamics Simulation Study on the Interactions of Mixed Cationic/Anionic Collectors on Muscovite (001) Surface in Aqueous Solution.

In this study, the adsorption mechanisms of dodecylamine hydrochloride(DDAHC), sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate(SDBS), and their mixed anionic/cationic collectors at ten different molar ratios on a muscovite (Mcv) surface in neutral aqueous solution were assessed by molecular dynamics simulations (MDS). According to the snapshot, interaction energy, radial distribution function (RDF), and density profile between the Mcv surface and collector molecules, the individual DDAHC collector was an effective collector for the flotation of Mcv. The molar ratio of anionic/cationic collectors was determined to be an essential factor in the flotation recovery of Mcv. The DDAHC collector was involved in the adsorption of the mixed anionic/cationic collectors on the Mcv (001) surface, whereas SDS and SDBS collectors were co-adsorbed with DDAHC. The mixed cationic/anionic collector showed the best adsorption on the Mcv surface in a molar ratio of 2. Additionally, SDBS, which has one more benzene ring than SDS, was more likely to form spherical micelles with DDAHC, thus resulting in better adsorption on the Mcv surface. The results of micro-flotation experiments indicated that the DDAHC collector could improve the flotation recovery of Mcv in neutral aqueous solution, which was in agreement with MDS-derived findings. In conclusion, DDAHC alone is the optimum collector for Mcv flotation under the neutral aqueous conditions, while the mixture of DDAHC and SDBS collectors (molar ratio = 2:1) exhibits the similar flotation performance.