Flotation Collector Research Articles

Effects of the Goethite Surface Hydration Microstructure on the Adsorption of the Collectors Dodecylamine and Sodium Oleate.

Dodecylamine (DDA) and sodium oleate (OL) are commonly used collectors in the reverse flotation and the direct flotation of goethite. However, the flotation mechanisms of DDA and OL on the goethite surface remain unclear. In this study, the first-principles density functional theory calculations were used to reveal the role of the hydration of the goethite surface and its effects on flotation reagents from a microscopic perspective. The calculation results showed that DDA was adsorbed on the surface of goethite by hydrogen bonds in the absence of hydration. However, the existence of the hydration microstructure hindered the formation of hydrogen bonds and made it difficult for DDA to be adsorbed on the goethite surface. In the OL system, oleate ions are chemically adsorbed on the surface Fe sites of goethite in the absence of hydration, while in the presence of hydration, the oleate ions were adsorbed on the H-terminal hydration surface of goethite by hydrogen bonds. This work sheds new light on the roles of the hydration microstructure and the adsorption mechanism of the flotation reagent on the oxide minerals.

Beneficiation of Bastnaesite Ore with New Flotation Collector Ligands

Beneficiation of Bastnaesite Ore with New Flotation Collector Ligands

Coal flotation in a low-rank carbonaceous mineral using 3-phenyl-1-propanol as a collector reagent

In the present work, 3-phenyl-1-propanol is proposed as a new collector for coal flotation in a low-rank carbonaceous mineral containing 2.0% of carbon and basic groups predominantly on the surface. Hydroxyl and carbonyl groups, as well as unsaturated carbon chains, were identified by FT-IR. Microflotation tests were conducted to evaluate and compare the effectiveness of the collector proposed with the one obtained using kerosene, diesel and 1-butylamine. Results show that the highest coal recovery is obtained with 3-phenyl-1-propanol. Mineral has a negative zeta potential in the pH range 2–13, but it does not show an isoelectric point. Furthermore, the zeta potential is modified by the collector. After conditioning, signals corresponding to the collector were identified in the mineral surface by FT-IR. A Box-Behnken experimental design was used for optimization of mineral Recovery and Clean Coal Recovery by flotation. Results showed that pH has not a significant effect on the mineral Recovery, however flotation time and volume of 3-phenyl-1-propanol have a significant direct effect. Optimal conditions for mineral Recovery were pH 8.5 and 84.5 µL of collector for 0.5 g of mineral. For Clean Coal Recovery; pH, flotation time and volume of 3-phenyl-1-propanol have a significant effect. Optimal conditions were pH 4.0, flotation time 2.5 min and 87.9 µL of collector for 0.5 g of mineral.

A novel metal–organic complex surfactant for high-efficiency mineral flotation

The separation of scheelite from other calcium-containing minerals via flotation is problematic because of their similar surface properties and response to conventional anionic collectors. Herein, we report, to the best of our knowledge, a new type of metal–organic complex collector prepared via self-assembly of benzohydroxamic acid (BHA) ligands and Pb(II). A new Pb(II) complex [Pb6L8(NO3)3]NO3 (HL = BHA) is synthesized using coordination reactions and structurally characterized using single-crystal X-ray diffraction. Further, its flotation behavior and adsorption mechanism at the solid–liquid–gas interface were investigated via flotation experiments, zeta potential, XPS, TOF–SIMS, AFM, SFG-VS, adsorption capacity, froth-stability testing, etc. The results show that the developed complex exhibited good collecting ability and absolute specificity for scheelite. The complex was chemically adsorbed on the scheelite surface by combining the lead functional group and oxygen atoms of scheelite to form multilayer adsorbents, rendering the scheelite particle surface strongly hydrophobic. The complex collector and frother assembly are co-adsorbed at the gas–liquid interface, which significantly reduced the solution surface tension, forming a stable foam layer. Therefore, selective flotation was achieved through the targeted adsorption at interfaces. A simplified flotation process for scheelite using complex collector has been successfully applied in industry, significantly improving the recovery of scheelite. This high selectivity makes metal–organic complex a novel and promising collector for high-efficiency mineral flotation and contributes to the efficient and clean development of mineral resources.

New perspectives in iron ore flotation: Use of collector reagents without depressants in reverse cationic flotation of quartz

The reverse flotation of the iron ore with etheramine collector is significantly impacted when the iron-bearing silicates and the kaolinite are present in the silicates gangue mineral complex. This paper aims to propose a new amidoamine collector N-[3-(Dimethylamino)propyl]dodecanamide for iron ore reverse flotation with a potential of removing the iron oxides depressant. The contact angle and electrophoretic mobility measurements as well as the flotation experiments were performed on the pure quartz, kaolinite and hematite samples to compare its effect with the etheramine which is widely used as collector in reverse flotation of iron ores. Infrared spectroscopy was performed to study the adsorption of the amidoamine collector on the surface of the minerals studied.Amidoamine collector showed a significant selectivity towards quartz while the flotation of hematite and kaolinite were inhibited at pH 10 without the presence of a depressor. A total floatability of quartz was explained by increased contact angle from 10° to about 50° without impacting significantly the contact angle measured on the hematite (9.4° to 17°). Surface hindrance effect caused by the structure of the N-[3-(Dimethylamino)propyl]dodecanamide collector on the hematite surface is the most suitable hypothesis concerning the high selectivity regarding the iron ore reverse flotation process.

Unravelling the performance of oxycarbonyl-thiocarbamate collectors on chalcopyrite using first-principles calculations and micro-flotation recoveries

First-principle quantum mechanical density functional theory (DFT) was employed to explore the bonding behaviour, adsorption energies and electronic properties directly related to the reactivity’s of O-butyl-N-ethoxycarbonyl-thiocarbamate (BECTC), O-isobutyl-N-ethoxycarbonyl-thiocarbamate (IBECTC), O-butyl-N-butoxycarbonyl-thiocarbamate (BBCTC), O-isobutyl-N-butoxycarbonyl-thiocarbamate (IBBCTC), and O-isobutyl-N-isobutoxycarbonyl-thiocarbamate (IBIBCTC) with the chalcopyrite (CuFeS2) (112) surface and complimented by micro-flotation recoveries of the chalcopyrite. The partial density of states (PDOS) of the isolated oxycarbonyl-thiocarbamate collector showed that the sulphur atom (S1) was more active and will be more reactive during adsorption. Adsorption of the oxycarbonyl-thiocarbamate collectors preferred the Cu atom over Fe atoms. The adsorption energies and micro-flotation recoveries yielded similar trends and the order followed: BBCTC > IBIBCTC > BECTC > IBBCTC > IBECTC, which showed that BBCTC exhibited the strongest exothermic adsorption. This showed that the adsorption energies that determined how a collector binds to the mineral surface can predict the flotation recoveries. The PDOS and atomic population charges after adsorption showed that both Cu and S1 atoms lose charges (electron donor) forming σ-bonds, and simultaneously, dative π-bonds. The results also showed that BBCTC and BECTC are better collectors for the selective flotation of chalcopyrite minerals and indicated that a straight hydrocarbon chain gave stronger adsorption than a branched hydrocarbon chain.

Increasing the efficiency of phosphate ore processing using flotation method

The paper presents flotation of two phosphate ore samples of different origin. Statistical analysis was used to study the effect of operating parameters on flotation efficiency. The paper proposes to increase the efficiency of flotation processing of magmatic phosphate ore with a low grade of the valuable component (P2O5 = 10.88 %), containing nepheline and feldspars, by means of direct anionic flotation. Authors present an optimization of anionic flotation using tall oil fatty acids mixed with anionic phospholane as an anionic collector. The effect of adding soda ash to compensate for the influence of calcium cations on technological parameters of P2O5 flotation was examined. The results of studying the flotation of nepheline ore (flotation tailings of magmatic phosphate ore) showed that replacement of phospholane with oxyethylated isotridecanol allowed to obtain a high-quality concentrate. It was estimated that with the addition of Na2CO3 in the amount of 2,000 g/t, a concentrate was obtained with the grade and recovery of phosphorus pentoxide equal to 39.15 and 94.19 %, respectively. The paper proposes to increase the efficiency of flotation processing of sedimentary phosphate ore with a low grade of the valuable component (P2O5 = 22.5 %), containing gypsum and quartz, by means of desliming followed by anionic or cationic reverse flotation. Tall oil fatty acid with anionic phospholane was used as a collector in anionic reverse flotation, and amine was used in cationic reverse flotation. Sodium tripolyphosphate was used as a P2O5 depressant. It was found to be an effective depressant in both anionic and cationic flotation. When analyzing the statistical plan, it was estimated that the maximum grade of the valuable component in the concentrate (P2O5 = 31.23 %) and the recovery to concentrate of 95.22 % were obtained in the chamber product at amine consumption of 950.88 g/t and sodium tripolyphosphate consumption of 500 g/t.

Effect mechanism of nonane-1,1-bisphosphonic acid as an alternative collector in monazite flotation: Experimental and calculational studies

Monazite ((Ce, La)PO4) is one of the major types of light rare earth minerals from which the light rare earth elements cerium (Ce) and lanthanum (La) are economically extracted. Flotation is extensively used to recover fine-grained monazite. Sodium oleate (NaOL) is considered as the collector with strong collecting ability for monazite flotation. However, this study shows that its collecting ability is still limited. In this paper, a phosphonic acid, nonane-1,1-bisphosphonic acid (C9-BPA), was employed as the novel collector in place of NaOL. Flotation experiments show that even when the C9-BPA dosage is less than one-fifth of the NaOL dosage, the monazite recovery using C9-BPA as the collector is approximately 22 wt% higher than that using NaOL. The mechanism by which C9-BPA adsorbs on monazite was investigated using zeta potential, infrared (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements as well as first-principles calculations. Zeta potential measurements show a more significant decrease in the zeta potentials of monazite after the addition of C9-BPA compared to those after the addition of NaOL. For C9-BPA-treated monazite, the characteristic peaks of C9-BPA are observed in the IR and C 1s XPS spectrum, whereas for monazite treated by NaOL, no characteristic peak of NaOL was observed. Experimental results show that C9-BPA has a stronger affinity towards the monazite surface than NaOL as confirmed by the higher adsorption energy of CP-BPA on the monazite surface (‒204.22 kJ/mol) than NaOL (‒48.48 kJ/mol). This study demonstrates an extensive application value and prospect of C9-BPA in monazite flotation and helps design novel collectors with strong collecting ability for monazite flotation.

Separation of wolframite ore by froth flotation using a novel “crab” structure sebacoyl hydroxamic acid collector without Pb(NO3)2 activation

In this study, a new hydroxamic-acid molecule - sebacoyl hydroxamic acid (SHA) was synthesized and characterized. It was the first time that SHA with dual hydroxamic acid groups of “crab” structure was used as a collector for wolframite flotation, and its collecting ability was compared with the traditional collector benzohydroxamic acid (BAH) in the presence or absence of lead ions. In micro-flotation experiments, the wolframite recovery using 4 × 10−4 mol/L SHA collector alone was 30% higher than that using 4 × 10−4 mol/L BHA collector and 1 × 10−4 mol/L Pb(NO3)2 activator. The results of bench-scale flotation experiments showed that the WO3 recovery of wolframite concentrate with 180 g/t SHA was 10.05% higher than that with 360 g/t BHA and 300 g/t Pb(NO3)2. Therefore, using SHA collector with “crab” structure for wolframite flotation can not only improve the separation index at a low dosage, but also eliminate the use of Pb(NO3)2.

The Application of a Nitrile-based Collector in the Flotation of a Platreef PGM Ore

ABSTRACT Declining ore grades, coupled with the increasing mineralogical complexity of ores, have forced the platinum group mineral (PGM) industry to search for collectors that outperform the conventional options. One such potential alternative is Nouryon’s Tecflote™ family of nitrile-based collectors for sulfide flotation; whilst notable success has been reported in the copper industry, the potential value of these in the PGM industry has not yet been evaluated. This study employed batch rougher flotation tests coupled with mineralogical analysis of tailings samples to investigate the application of Tecflote S11 as a partial or complete replacement of thiol collectors in the flotation of a PGM bearing Platreef ore. Tecflote S11 as sole collector and in combination with different thiol collectors were investigated. At low dosages of 80 g/t, the Tecflote and PAX as single collectors achieved similar 3E (Pt, Pd and Au), Ni, and Fe recoveries, with Tecflote proving to be the more powerful Cu collector. At higher dosages of 160 g/t, PAX outperformed Tecflote in terms of 3E, Cu, Ni and Fe recoveries. A 50:50 mass% combination of the Tecflote with either DTP, DTC or PAX showed improved recoveries without a loss in 3E grade. The Tecflote-PAX combination achieved the highest 3E, Cu and Ni recoveries. Under these conditions, fully liberated PGMs and those associated with liberated base metal sulfides (BMS) were recovered. Overall, the study demonstrated that the Tecflote requires the backing of a strong thiol-based collector to achieve an improved flotation response for the Platreef ore.

Separation of nickel and zinc from aqueous solution using triethylenetetramine

This study investigates the most suitable conditions for the combined separation of nickel and zinc ions from aqueous solution using triethylenetetramine (Trien) as a neutral organic chelating ligand and sodium dodecyl sulfate (SDS) as an anionic collector for ion flotation. The interaction of nickel ions with Trien at various pHs and Trien concentrations, and that of nickel ions with SDS, are studied spectrophotometrically. The results show that most suitable conditions for ion flotation are a pH of 9.7, a Trien/Ni(II) mole ratio of 2 and an SDS/Ni(II) mole ratio of 2. Flotation results for the nickel–zinc–SDS-Trien solution show that nickel ion removal is higher than that for zinc ions, indicating that the order of ion removal is opposite to the order of increasing crystal ionic radius. The stability constant of the nickel-Trien complex is greater than that for the zinc-Trien complex, leading to higher Trien interactions with nickel ions. At a pH of 9, the removal of nickel and zinc ions reaches a maximum of 88.4 and 79.9% respectively, corresponding to a 9% higher removal of nickel ions compared to zinc ions.

Optimization of conventional hydroxamic acid for cassiterite flotation: Application of structural modification under principle of isomerism

In this paper, through the structural modification of N-phenyl formohydroxamic acid (NPFHA), an isomer of benzohydroxamic acid (BHA), we designed and synthesized a series of N-phenyl hydroxamic acids (NPHA), including N-phenyl acetohydroxamic (NPHA-2), N-phenyl butyrohydroxamic acid (NPHA-4), N-phenyl hexanohydroxamic acid (NPHA-6) and N-phenyl octanohydroxamic acid (NPHA-8), and first introduced them as flotation collectors for selectively separating cassiterite from quartz and feldspar. Micro-flotation tests indicated that with increase of non-polar carbon chain length, the collecting ability to cassiterite improved dramatically. More to the point, compared to BHA, NPHA-6 and NPHA-8 possessed superior flotation performances to cassiterite and enabled the separation of cassiterite and quartz/feldspar over a wide pH range, with no application of frother or activator, providing a new insight into the development of cassiterite collector. Zeta potential experiments indicated that NPHA-8 chemisorbed onto cassiterite surfaces, with no significant adsorption to quartz or feldspar detected. DFT calculations, FT-IR and XPS analyses further demonstrated that NPHA-8 chemisorbed on cassiterite surfaces by forming C–O–Sn and N-O–Sn bonds, accompanied by proposing two interaction geometries, first with the same Sn atom of cassiterite surface, leading to a five-membered chelating ring, second with two different Sn atoms, resulting in constituting an irregular complex.

Proving the existence of nanobubbles produced by hydrodynamic cavitation and their significant effects in powder flotation

Selective attachment of nanobubles (NBs) generated in different conditions on the surface of valuable minerals during flotation separation was a challenge that needs to be addressed. This investigation filled this gap and proved the existence of NBs on the target mineral's surface and their selective effectiveness through the process. The bubble size analysis results showed that the mean diameter of bubbles was between 60 and 70 nm; thus, they could be correctly called “nanobubbles”. Flotation test results showed a significant increase in the flotation recovery (by 37%) and grade (more than 1%) of fine phosphate ore sample (d80: 37 µm) using NBs that generated in the presence of collector. Interestingly, surface analyses of flotation products showed that the amounts of flotation collector adsorbed onto the surface of floated particles was decreased in the presence of NBs compared with their absence. The change in the particle surface (zeta) potential in the presence of NBs also provides additional evidence of NBs “adsorbed” (i.e., the surface NBs) onto the particle surface. These results indicated that NBs produced by hydrodynamic cavitation could adsorb onto the target mineral particles. This adsorption could change their surface properties, improve their hydrophobicity and surface potentials, and enhanced the bubble-particle attachment in flotation.

Thermodynamic stability diagram of the copper/water/amylxanthate flotation system

The purpose of this work was to obtain the thermodynamic stability diagram that characterizes the copper/water/amylxanthate flotation system, as part of the theoretical foundation necessary for the analysis of the copperion flotation process with the flotation collector reagent potassium amylxanthate. From the system of fundamental chemical reactions and with the help of the Medusa software, the Eh-pH diagram was obtained, in which the stability zones of the different chemical species are defined and it is established that in the pH range from 4 to 13, the xanthogenic species of copper(I) and (II) coexist, whose ratio decreases with the increase of pH.

Hydroxypropyl amine surfactant: A novel flotation collector for efficient separation of scheelite from calcite

In this work, N-tetradecyl-isopropanolamine (NTIA) is synthesized and used as a new collector on the flotation separation process of scheelite from calcite to further improve the efficiency of the selective flotation. The effects of NTIA on minerals are investigated through microflotation experiments. Flotation experimental results show that NTIA provides good flotation and separation effects on the scheelite in a wide range of pulp pH (6.0–10.0). At pH 7.0, the flotation recovery of scheelite reaches 96.89%, while calcite to only 10%. Moreover, it also reveals an efficient separation effect for artificial mixed minerals of scheelite and calcite under certain conditions. The adsorption behavior of NTIA on scheelite is further studied using wettability test, infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and zeta potential analysis. The results demonstrate that the surface of scheelite is preferentially modified, increasing its hydrophobicity after treatment with NTIA. Meanwhile, under the action of hydrogen bonding and strong electrostatic field in the hydrophilic N–H group of NTIA, the NTIA molecules are absorbed on the scheelite surface.

Aspects of Talc Grinding in the Presence of Sodium Dodecyl Sulfonate

AbstractIn this study, the effect of sodium dodecyl sulfonate (SDS), as a well‐known flotation collector, on talc grinding was investigated using a statistical design in terms of solids%, pH, grinding time, and SDS dosage taking the d80 of the ground product as a response. The results indicated that the factors under study significance order were grinding time > solids% > SDS dosage > pH. In addition, the interactions between solids % and the grinding time and between the solids% and SDS dosage significantly affected the product d80. More interestingly, the presence of SDS not only improves the grinding process at short grinding times but also it enhances the grinding at higher pH values. The optimum conditions for talc grinding are similar in the absence or presence of SDS in terms of factors under study, except for solids%. The vital role of SDS, as a grinding aid, is the production of particles with the same fineness or even finer at higher solids % which leads to an increase in the mill throughput. The smallest d80 was obtained at 60% solids, 60 min, pH 4, and 2 kg t−1 of SDS.

An HPLC Method for the Determination of Amines in Flotation Pulp Based on Derivatization

Alkyl amines are surfactants used as quartz collectors in the reverse flotation of phosphate ores. It is important in both research and industrial practice to quantify amine concentration in the solution and/or wastewater. A simple and rapid method using high-performance liquid chromatography (HPLC) was developed to quantitatively determine the concentration of amine collectors (including dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine) in a mineral flotation system. The method involved a sample derivatization procedure with 9-fluorenyl methoxycarbonyl chloride (FMOC-Cl) and separation/determination by HPLC coupled with a fluorescence detector. The calibration curves showed good linearity (R2 > 0.9956) in the range of 0.20–5.00 µg/mL, and the recoveries of dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine were in the ranges of 84.93–97.64%, 89.93–101.92%, 85.29–98.37%, and 93.57–103.26%, respectively. The method was successfully used to quantify amines in wastewater from flotation experiments and artificial flotation wastewater (amine solution after activated carbon adsorption). The results from the analysis of four amines in the solution demonstrated that the proposed method is suitable for the simultaneous determination of amines in flotation pulp and wastewater.

Removal of Zn(II) and Mn(II) by Ion Flotation from Aqueous Solutions Derived from Zn-C and Zn-Mn(II) Batteries Leaching

The Zn(II) and Mn(II) removal by an ion flotation process from model and real dilute aqueous solutions derived from waste batteries was studied in this work. The research aimed to determine optimal conditions for the removal of Zn(II) and Mn(II) from aqueous solutions after acidic leaching of Zn-C and Zn-Mn waste batteries. The ion flotation process was carried out at ambient temperature and atmospheric pressure. Two organic compounds used as collectors were applied, i.e., m-dodecylphosphoric acid 32 and m-tetradecylphosphoric 33 acid in the presence of a non-ionic foaming agent (Triton X-100, 29). It was found that both compounds can be used as collectors in the ion flotation for Zn(II) and Mn(II) removal process. Process parameters for Zn(II) and Mn(II) flotation have been established for collective or selective removal metals, e.g., good selectivity coefficients equal to 29.2 for Zn(II) over Mn(II) was achieved for a 10 min process using collector 32 in the presence of foaming agent 29 at pH = 9.0.

Preparation and properties of dodecylamine microemulsion for the flotation of quartz and magnetite

Dodecylamine (DDA) can only be used with acidification in the reverse flotation of iron ore. To solve this problem, this paper proposed a novel water-in-oil microemulsion with DDA prepared using one or two of AEO-3, OP-10, and Tween-80 & Span-80 as the surfactants, 2-octanol as the cosurfactant, and DDA and kerosene as the oil phase. The freezing point, surface tension, droplet size distribution, and zeta potential were determined for the DDA microemulsion. The results showed that the freezing point of the produced DDA microemulsion can be reduced to –12.5 °C. Moreover, the surfaces of its droplets dispersed in aqueous solution are positively charged at pH values less than 10.0. The flotation performance of the DDA microemulsion was investigated by flotation tests. From the results, DDA microemulsion exhibited good dispersibility and surface activity, thereby confirming its ability to effectively reduce air–water interfacial tension. In addition, it was found to have good adaptability to temperature and pulp pH, yielding a magnetite concentrate with 68.54% Fe and 3.60% SiO2 from magnetite with 64.93% Fe and 9.12% SiO2 using 45 g/t DDA microemulsion. Therefore, the proposed DDA microemulsion can be used as an efficient collector in the reverse flotation of magnetite.

The flotation behavior and adsorption mechanism of a new cationic collector on the separation of spodumene from feldspar and quartz

A new collector N-{3-[(2-propylheptyl)oxy]propyl}propane-1,3-diamine (PPPDA) was successfully synthesized in laboratory. The flotation behaviors of PPPDA on the separation of spodumene from feldspar and quartz were investigated through single mineral flotation experiments. The effects of pH, PPPDA concentration, metal ions concentration and the adding sequence of these reagents during the separation process were evaluated. At the condition of PPPDA concentration of 0.171 mmol/L, Ca(II) concentration of 0.171 mmol/L and pH 5.2, the greatest difference of recovery between spodumene and the gangues (feldspar and quartz) was achieved. The recovery of spodumene, feldspar and quartz under this condition was 5.39%, 89.31% and 91.7% respectively, which indicated that PPPDA had the potential to be used as a collector in reverse flotation of crude concentrate. The adsorption mechanism was investigated systematically by zeta potential, FT-IR, AFM, and adsorption amount measurements. The results demonstrated that PPPDA could be adsorbed on spodumene, feldspar and quartz through both electrostatic attraction and hydrogen bond. The amounts of PPPDA adsorbed on feldspar or quartz were much more than those on spodumene, which led to higher recovery for feldspar and quartz. The difference of the distance between the two nitrogen atoms in PPPDA and the distance between the two oxygen atoms on mineral surfaces, that is the “Spatial Matching Effect”, might lead todifferent adsorption models. Furthermore, in the presence of Ca(II), there was the competitive adsorption between Ca(II) and PPPDA. The spodumene preferred to adsorb Ca(II), while feldspar and quartz preferred to adsorb PPPDA. Therefore, Ca(II) could expand the floating difference of spodumene from feldspar and quartz with PPPDA as the collector.