Compound Collector Research Articles

Study on stability and characterization of high internal phase water-in-oil compound collector emulsion

To address the high consumption and poor environmental performance associated with traditional coal slime flotation oils, we have developed a high internal phase water-in-oil (HIP W/O) emulsion using methyl oleate and methyl laurate as collectors. This study examines the factors influencing emulsion stability and water dispersion. Comparative flotation tests were performed, and the emulsion’s microstructure and rheological properties were assessed using freeze-scanning electron microscopy and a rheometer. The optimal emulsion formulation contained 5.56 vol% of a compound collector, 4.44 vol% Span 80, and 90 vol% of a sodium chloride and gelatin water solution. The incorporation of gelatin into the water phase established a three-dimensional gel network within the emulsion droplets, significantly enhancing both viscosity and stability. This emulsion reduced compound collector consumption by approximately 84 % while maintaining comparable flotation performance. Its fine particle distribution and effective coal surface adsorption highlight its potential as an environmentally friendly option for fine coal flotation, thus promoting cleaner and more efficient coal utilization.

Utilization of the mixture of ethylene tar and different petrochemical by-products as collectors for coal flotation

ABSTRACT The ethylene tar and mixtures of ethylene tar with other petrochemical by-products were used as collectors for coal flotation. The results showed that the 1# compound collector was better than kerosene in terms of selectivity and collectibility for coal flotation. When the collector dosage was 1500 g/t, the yield of clean coal using the 1# compound collector increased by 4.05%, and the reduction in ash content was 0.36% lower compared to using kerosene. The mechanism of action of 1# compound collector on the coal surface was analyzed in combination with GC-MS tests and FTIR tests. The 1# compound collector contains more aromatics, olefins and heteropolar substances than kerosene. When the aromatics in the 1# compound collector interact with the nonpolar sites on the coal surface via π–π stacking interactions, some of the polar sites sandwiched between the aromatic compound molecules are covered. The olefins contained therein engage with the nonpolar sites on the surface experiences interactions attributable to van der Waals forces. The oxygenated functional groups of alcohols, acids, esters and carbonyl compounds engage with the polar sites on the surface of the particles through hydrogen bonding.

2D-3D cyclodextrin-modified montmorillonite assembly for efficient directional capture of amines

Shale gas exploitation produces a large amount of waste liquid, which cannot be fully recovered and discharged. Discharged wastewater contains several chemicals, including petroleum hydrocarbons, salts, and heavy metals. Amine compounds can absorb harmful gases but may lead to the presence of these compounds in wastewater. Some amine compounds may cause DNA mutations and health threats to humans and animals. Inspired by the assembly of artificial two-dimensional structures, this paper attempts to shape montmorillonite (MMT) with a natural layered structure. Specifically, a functional 2D/3D amine compound collector within the limitations of 2D MMT (Mt) was prepared by self-assembling cyclodextrin molecules. With the assembly of cyclodextrin (CD) molecules, the two-dimensional Mt. layer length increased from 12.14 to 19.11 Å. Adsorption experiments revealed that functional MMT powder (FMP) has good trapping ability for amines, that the adsorption of amine groups on FMP decreases with increasing temperature, and that it has greater potential to remove amine compounds with fewer carbon chains. Through molecular dynamics simulation, it was found that there was a molecular binding energy between FMP and branched polyethyleneimine (BPEI), indicating that FMP had a spontaneous adsorption effect on BPEI. Furthermore, their adsorption favored the Langmuir isotherm model and the pseudo-second-order kinetic model. This study also provides a new collector for the total organic carbon (TOC) advanced treatment system. Compared with that of ozone and UV treatment, the removal rate of FMP is 10 times higher than that of activated carbon and active resin, which can better remove polar molecules and is beneficial for gas field water recovery.

Study on flotation and molecular simulation of gasification fine slag enhanced by compound collector

ABSTRACT Aiming at the problem that coal gasification fine slag is difficult to float effectively, this paper combines flotation experiments and molecular simulation methods to study the mechanism of composite collectors on the flotation performance of gasification fine slag. In the aspect of molecular simulation, the quantum chemical characteristics of collector molecules and coal molecules in gasification fine slag were studied by density functional theory (DFT) calculation, and the electrostatic potential and frontier orbitals were calculated. Then, the flotation behavior of composite collectors in gasification fine slag was simulated by molecular dynamics. It was found that dodecane and dodecylamine had the best flotation effect as collectors. Finally, the flotation experiment verified that the recovery rate and other related indexes of gasification fine slag were better when dodecane and dodecylamine were used as collectors.

Enhancement mechanism of polysorbate surfactant at solid/liquid and gas/liquid interfaces in magnesite tailings flotation desilication via MD and DFT calculations

To achieve the efficient flotation desilication of magnesite tailings (MT), this research systematically investigated the selective adsorption behavior of dodecylamine (DDA) and its compound collectors formed by mixing with Polysorbate surfactants and DDA. The investigation integrated experimental and simulation approaches. The results of the flotation experiment showed that the compound collector improved the MgO grade of the concentrate by 0.20% compared to DDA alone. Additionally, the SiO2 content was reduced by 1.04%, and the concentrate achieved a MgO grade of 41.95%. Molecular simulations provided new insights into the enhanced flotation mechanism with compound collectors, focusing on the size effect of collectors at the solid/liquid interface and bubble modification of collectors at the gas/liquid interface. The analysis indicates that small-size compound collectors can optimally utilise the collecting performance of individual DDA molecules, thereby effectively reducing reagent consumption per unit. Correlation tests indicate a notable enhancement in the hydrophobicity of the quartz surface subsequent to the application of the compound collector, suggesting that the compound collector exhibits a more solidophilic characteristic than DDA. The collectors of the compound facilitate the movement of water molecules on the bubble surface. This leads to a significant increase in the hydrophobicity of the bubble surface, which in turn increases the likelihood of bubble-particle contact collision and adhesion. Compared to DDA, the low dosage of compound collector has the potential to reduce costs and lay the foundation for industrial-grade MT flotation purification.

Investigation of Alkane-Assisted dodecylamine on flotation desilication of magnesite Tailings: Molecular dynamics simulations and model optimization

Investigating the reverse flotation desilication process of magnesite tailings (MT) holds substantial merit in the context of magnesium metal recovery from solid waste. However, scant attention has been devoted to exploring the influence of the carbon chain length of diverse alkanes on the reverse flocfloatation desilication of MT. This research systematically delved into the selective adsorption behavior exhibited by dodecylamine (DDA) and its compound collectors on the surfaces of quartz and magnesite. As the carbon chain length of alkanes increases, the efficacy of reverse flotation desilication of MT diminishes. Under optimized conditions, the concentration of MgO in the concentrate registers a 0.93% increment, accompanied by a 2.05% reduction in SiO2 content. The optimal MgO grade attains 42.68%. The augmenting carbon chain length of alkanes leads to a decline in the dispersibility of the compound collector and a reduction in the diffusion coefficient of the monolayer film at the alkane/water interface. The compound collector, comprising n-heptane and DDA, manifests a noteworthy synergistic promotion effect on the flotation desilication of MT. This effect reduces the multilayer adsorption of DDA, promotes more hydrogen bonding formation, and favors DDA adsorption on the quartz surface over magnesite. Consequently, issues related to froth entrapment and poor selectivity are alleviated. Longer alkane chains in the compound collectors result in a stronger van der Waals force effect between the carbon chains. This effect causes DDDA to slide more easily on the quartz surface, which is not conducive to enhancing the hydrophobicity of the surface. Furthermore, alkane-induced hydrophobic flocculation increases the floccules size of quartz, enhancing the likelihood of bubble-particle adhesion. This investigation elucidates the molecular-level mechanism underlying alkane hydrophobic flocculation with varying chain lengths, contributing a theoretical foundation and technical support for the large-scale MT management and the sustainable production of magnesium metal.

Effect of Carboxyl Group Position on Assembly Behavior and Structure of Hydrocarbon Oil-Carboxylic Acid Compound Collector on Low-Rank Coal Surface: Sum-Frequency Vibration Spectroscopy and Coarse-Grained Molecular Dynamics Simulation Study.

In this work, the assembly behavior and structure of a compound collector with different carboxyl group positions at the low-rank coal (LRC)-water interface were investigated through coarse-grained molecular dynamics simulation (CGMD) combined with sum-frequency vibration spectroscopy (SFG). The choice of compound collector was dodecane +decanoic acid (D-DA) and dodecane +2-butyl octanoic acid (D-BA). CGMD results showed that the carboxyl group at the carbon chain's middle can better control the assembly process between carboxylic acid and D molecules. SFG research found that the carboxyl group at the carbon chain's termination had a greater impact on the displacement of the methyl/methylene symmetric stretching vibration peak, while the carboxyl group at the carbon chain's middle had a greater impact on the displacement of the methyl/methylene asymmetric stretching vibration peak. The spatial angle calculation results revealed that the methyl group's orientation angle in the D-BA molecule was smaller and the carboxyl group's orientation angle in the BA molecule was bigger, indicating that D-BA spread more flatly on the LRC surface than D-DA. This meant that the assembled structure had a larger effective adsorption area on the LRC surface. The flotation studies also verified that the assembly behavior and structure of D-BA with the carboxyl group at the carbon chain's middle at the LRC-water interface were more conducive to the improvement of flotation efficiency. The study of interface assembly behavior and structure by CGMD combined with SFG is crucial for the creation of effective compound collectors.

Enhanced flotation separation of low-rank coal by using polar/nonpolar binary compound collector

ABSTRACT The surface hydrophobicity of low-rank coal is meager, hindering the efficient adsorption of hydrocarbon oil on its surface. Consequently, the hydrophobicity modification of the coal surface is adversely affected, making flotation separation of the coal-gangue challenging. To achieve accurate separation of low-rank coal and gangue, this paper proposes the concept of a polar-nonpolar binary mixed collector to enhance the technology of flotation separation of low-rank coal. The study examined the effects of single polar/nonpolar collectors and compounded collectors on low-rank coal. The results showed that the flotation efficiency of oleic acid and lauric acid methyl ester as single collector was superior to all others. Moreover, the flotation efficiency of single nonpolar or polar collector was lower than that of nonpolar/polar compounded collector. Furthermore, the flotation yield of coal concentrate initially increased and then decreased with the increase of dodecane mass fraction. The ideal nonpolar and polar ratios ranged from 6: 4 to 8: 2. We analyzed the mechanism for boosting the floatability of low-rank coals using the combined collector through adhesion angle, contact angle, and X-ray photoelectron spectroscopy (XPS) tests. The adhesion angle displayed a much greater increase following treatment with the compounded collector than with the single collector. Within 10–20 seconds, the growth was swift. The adhesion angle significantly exceeded that of the single collector following treatment with the compounded collector. Furthermore, the inclusion of a suitable quantity of polar reagents proved effective in augmenting the coal samples’ hydrophobic C-C/C-H chemical structure whilst decreasing the content of hydrophilic oxygen-containing groups. The use of alkyl acid ester addition in the composite reagent significantly improves the separation efficiency of a single flotation reagent and is expected to break through the current technical bottleneck of poor effect and high cost of flotation reagents.

Influence mechanism of a compound collector from coal tar and dodecane in the flotation of fine molybdenite particles

With the depletion of high-grade molybdenum (Mo) deposits, it is more pressing to separate the low-grade deposits effectively due to the large demand for Mo. However, traditional hydrocarbon oil collectors such as kerosene suffered low collecting capacity for low-grade ores because of the fine disseminated nature and crystal anisotropy of molybdenite. In this study, the effect of a compound collector prepared from coal tar and dodecane (CTD) on the flotation of fine molybdenite was investigated by micro-flotation experiments, bubble-particle attachment tests, gas chromatography-mass spectrometry (GC–MS), density functional theory (DFT) calculations, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The results of micro-flotation experiments demonstrated that CTD improved the flotation recovery of fine molybdenite dramatically compared with dodecane and kerosene, the fine particles pretreated with CTD had a better affinity for bubbles, and a stronger mineralization efficiency was achieved than that with dodecane as the improvement of the surface coverage and attachment rate constant. The results of GC–MS, FTIR, and DFT calculations indicated that there were plenty of compounds with benzene rings in the CTD, especially for phenanthrene and naphthalene, which showed a stronger interaction on the (100) plane of molybdenite than dodecane, thereby proving a stronger affinity for hydrophilic planes. The results of XPS analysis depicted that more adsorption amounts were achieved on molybdenite by CTD than that of dodecane, and contact angle test results further demonstrated that the effect of CTD was stronger than dodecane in improving the hydrophobicity of fine molybdenite particles. In general, the compound collector (CTD) is beneficial to the improvement of attachment rate of molybdenite particles to bubble and hydrophobicity of molybdenite particles, which improves the flotation recovery of fine molybdenite. The extract from coal tar had more affinity for the (100) plane of molybdenite compared to the (001) plane through DFT calculations. The finding has important reference value and guiding significance for the future research on collectors for fine molybdenite flotation.

Application and mechanism of a compound collector for the beneficiation of low-grade gold ore

High-efficiency beneficiation of low-grade gold ore becomes an inevitable trend with the depletion of high-grade gold ore. The work innovatively proposed a novel beneficiation process for a typical low-grade gold ore through developing compound collector and discussed the adsorption mechanism. PAX and ADD are most suitable compound collector when the ratio is 3:1 and dosage is 100 g/t. A concentrate with gold grade of 18.40 g/t and recovery of 79.72% is obtained by the novel “one-stage rougher, three-stage cleaner, and two-stage scavenger” closed-circuit process, which has the advantages of low-cost, simple-process, and high-efficiency comparing with the conventional process. The FTIR spectra analysis shows that PAX is a saturated organic compound containing branched chains and ADD is a straight-chain organic compound containing unsaturated bonds. The adsorption of PAX or ADD on the gold ore is chemisorption process and the compound collector has a strong chemisorption capacity. The novel closed-circuit flotation process using compound collector develops an excellent beneficiation effect and provides a prospective and effective approach to concentrate low-grade gold ore.

Role of the Polar Proportion of Compound Collectors in Low-Rank Coal Flotation Upgrading: Insights from the Molecular Scale

The compound collector, composed of polar and nonpolar parts, is a current research hotspot in low-rank coal (LRC) flotation because of its outstanding flotation efficiency and cost-effectiveness. However, the selection of compound proportions lacks theoretical guidance. In this study, we comprehensively investigate the internal mechanism underlying the influence of the compound proportion (oleic acid (OA):dodecane (DD)) on LRC flotation. The molecular dynamics (MD) simulation between bubble and oil film was simultaneously employed to study the surface interactions between three phases in contact. The compound proportion of OA:DD = 1:3 was found to be the most conductive for Zhuanlongwan coal flotation, which provides a robust collecting capacity while minimizing excessive interaction with water. Thus, the spreading area is the largest and the interaction energy between collectors and LRC is the highest. Additionally, the oil film formed at this ratio has the best hydrophobicity, resulting in the fastest adhesion speed of the bubble and the most stable bubble adhesion. Proportions of OA:DD above 1:3 promote self-aggregation of polar collectors, leading to a worsened spreading of the oil film. Conversely, proportions below 1:3 result in weak interaction with LRC, leading to a smaller spreading area and reduced hydrophobicity. Ultimately, we propose the LRC–compound collector matching principle, which suggests that the best proportion of compound collectors fits well with the oxygen-containing sites on the LRC surface.

The removal of dolomite from collophane using reverse flotation process enhanced by compound collector

To improve the magnesia removal effect of collophane and increase the P2O5 grade of phosphorus concentrate, the fatty acid collector mixed with sodium dodecyl sulfate (SDS) was used as the compound collector in reverse flotation for magnesia removal in acid system. Solution surface tension measurement, Zeta potential test and infrared spectrum analysis were conducted to analyze the intensified effect of compound collector for dolomite removal. The results showed that under the conditions of grinding fineness -0.074 mm accounted for 89.8%, sulfuric acid dosage 12.0 kg/t, phosphoric acid dosage 3.0 kg/t, SDS compound proportion 3%, collector dosage 1.0 kg/t, the P2O5 grade of concentrate is increased from 25.7% to 29.94%. SDS can reduce the surface tension of slurry, which is conducive to the formation and stability of flotation foam. Zeta potential became negative due to the compound collector adsorbed on the mineral surface. Moreover, the -CH2 antisymmetric stretching vibration peak originated from fatty acid and SDS were detected after the interaction of collectors with dolomite. The compound collector was effectively adsorbed on the surface of dolomite, enhancing the magnesium removal effect of collophane.

Применение компаундных нефтесодержащих собирателей в процессе пенной сепарации алмазов

The object of this study is the process of diamond-containing kimberlites’ enrichment by foam separation. The subject of research is compound collectors for diamond flotation. The purpose of the study is to substantiate the possibility and choice of conditions for the use of Machchobin oil as a component of the base collector in the foam separation of diamonds. The objectives of the research are to establish the physico-chemical characteristics of Machchobin oil, fuel oil and their mixtures; assess their collecting ability; select the optimal composition of the collector; determine the effectiveness of a compound collector use in the technological process. The methods of rectification analysis of fractional composition, visiometric analysis of structure and phase composition, vibrational viscometry have been used to establish the physical and chemical characteristics of Machchobin oil, fuel oils and their mixtures. To estimate the collecting ability of the compound collector the methods of flotation and foam separation of diamonds and minerals of kimberlite on the laboratory installations of foamless flotation and foam separation have been applied. To determine the efficiency of the compound collector an automated foam separation unit has been used. Conducted physico-chemical studies have shown that when mixing fuel oil F-5 and degassed Machchobin oil, the dissolution of asphaltenes of fuel oil in low–molecular fractions of oil, and paraffins of oil – in medium-molecular fractions of fuel oil is observed. The formation of finely dispersed and colloidal solutions of high-molecular components of oil increases the adhesive activity and leads to an increase in the collecting capacity of the compound collector. The flotation studies have shown that the greatest extraction of diamonds into concentrate is achieved when using a mixture of fuel oil F-5 and Machchobin oil as a base collector at a ratio from 3:1 to 1:1. The tests carried out during the enrichment of the ore of the Aihal tube by foam separation have established an increase in diamond extraction using a compound collector by 1.1–2.1 %. By replacing the fuel oil fraction with oil, a reduction in reagent costs has also been achieved.

Investigation on mechanism of the oleic acid/methyl oleate/diesel ternary compound collector in low-rank coal flotation

Polar and compound collectors are current research hotspots in the field of low-rank coal (LRC) flotation. However, most studies only focus on the collecting ability of collectors while ignoring its selectivity. This study presents the design for a novel high-efficiency ternary compound collector (oleic acid (OA), methyl oleate (MO) and diesel) with great selectivity, strong collecting and spreading ability for Sujiagou LRC. In comparison to diesel, the clean coal yield is increased by 41.40%, and its ash content is reduced by 0.91% at optimal dosage of 2000 g/t. And we propose some new insights on the mechanism of ternary compound collector through density functional theory (DFT) calculations, focused beam reflectance measurement (FBRM), and molecular dynamics (MD) simulations. OA has the strongest collecting ability with the shortest adsorption distance and smallest frontier orbital gap, which ensures the flotation efficiency and collecting ability of ternary compound collector. The great selectivity of ternary compound collector owing to these two reasons: MO adsorbs more strongly on the LRC surface through the flat-lying adsorption at the junction of hydrophilic and hydrophobic parts; the “wasteful adsorption” on the gangue surface is prevented as the nonpolar parts of ternary compound collector attract polar collectors. Finally, a firm oil film with strong spreading ability is formed on the LRC surface, which can achieve a spread across the hydrophilic area even without the adsorption of polar collectors. The synergistic adsorption not only improves the collecting ability of the ternary compound collector but also ensures its selectivity.

Chemical and physical modification of low rank coal floatability by a compound collector

Effective collectors are essential for improving coal floatability. In this investigation, contact angle, X-ray photoelectron spectroscopy (XPS), optical micrograph, field emission scanning electron microscope (FE-SEM), and flotation tests were used to characterize chemical and physical modification of low rank coal floatability by a compound collector consisting of coal tar and diesel. XPS showed that the C-C/C-H content on coal surface after compound collector adsorption was higher than that on coal surface after diesel adsorption. Optical microscope image results showed that compound collector produced more flocs than diesel, which increased flotation efficiency. Contact angle results showed compound collector enhanced coal surface hydrophobicity more significantly than diesel. FE-SEM images illustrated that coal surface after compound collector adsorption was rougher than that after diesel adsorption, which accelerated the rupture of liquid film between coal particle and bubble. Therefore, coal floatability after compound collector adsorption was much better than that after diesel adsorption.

Flotation intensification of low-rank coal using a new compound collector

Traditional non-polar oil collectors cannot achieve high recovery of low-rank coal because of the presence of oxygen-containing groups at coal surface. In this study, a new mixture of fossil oil and oxygen containing compound (FO) was used to enhance low-rank coal flotation compared with that using traditional collector, diesel oil. The oil droplet-particle detachment, induction-time, stability of the bubble-particle aggregate, attachment angle test and chemical force microscopy (CFM) were selected to further analyze the strengthening mechanism of collectors. The results show that higher yield was obtained using FO than that using diesel. Compared with diesel, FO was easier to adhere and spread on coal surface. The shorter induction time, higher amplitude and bigger attachment angle in presence of FO indicated that the FO treatment enabled the particles to much easily adhere to bubble. CFM provided a new insight into intensification mechanism of collector by the direct measurement of interaction force.

Erratum to: Effect of Tannin on Compound Collector Adsorption and Stibnite and Arsenopyrite Flotation from Complex Ore

Erratum to: Effect of Tannin on Compound Collector Adsorption and Stibnite and Arsenopyrite Flotation from Complex Ore

Flotation intensification of the coal slime using a new compound collector and the interaction mechanism between the reagent and coal surface

Flotation reagents in particular the flotation collector plays a significant role in the cleaning efficiency of coal slimes in the coal preparation and utilization industry. A new collector (NC) was used to achieve the efficient cleaning of coal slimes. Comparing with the conventional flotation collector of diesel oil (DO), the higher yields and lower ash contents of clean coal with the higher combustible material recoveries could be obtained using the NC in flotation. The optimum NC dosage of 500g/t was acquired through the unit flotation tests. Fourier transform infrared spectroscopy (FTIR) and contact angle measurement were used to study the interaction mechanism between the flotation collector and coal surface. The results indicated that the stronger electron-attracting ability of the ester groups than that of the carbon-carbon double bond resulted in the more stable interaction between the NC and coal surface than that between the DO and coal surface. The contact angle of the coal slime wetting with the NC of 67.1° was larger than that with the DO of 62.6°, suggesting the stronger hydrophobicity of the coal slime with the NC than that with the DO. The chemical composition analysis results suggest that the NC belongs to a compound flotation reagent, which provides an alternative high-efficient collector for coal flotation industry.

Effect of Tannin on Compound Collector Adsorption and Stibnite and Arsenopyrite Flotation from Complex Ore

This study was supported by the Russian Foundation for Basic Research, project no. 16-05-00646a.

Effect of Tannin on Compound Collector Adsorption and Stibnite and Arsenopyrite Flotation from Complex Ore

Effect of Tannin on Compound Collector Adsorption and Stibnite and Arsenopyrite Flotation from Complex Ore