Bubble-particle Attachment Research Articles

Optimizing coarse chalcopyrite separation in fluidized bed flotation: Role of the self-generated bed

Coarse particle separation is important in mineral processing. In this study, the performance of coarse chalcopyrite ore separation (−600 μm, Cu grade 0.375 %) by fluidized bed flotation (FBF) was investigated and the basic function of fluidized bed on the particle separation is discussed. The chalcopyrite grain size distribution mainly ranges from 50 to 300 μm, with over 80 % of the grains being liberated. The results indicate that the FBF system can reject tailings with a yield of 48 % and a Cu grade of 0.06 %. Additionally, concentrate Cu grade reaches 0.62 %, which is around 1.65 times higher than feed, resulting in a total Cu recovery of 91.55 %. The introduction of a fluidized bed increases Cu recovery of −600 + 300 μm from 50 % to73%, as it improves the possibility of bubble-particle attachment, but the variation of bed height has little influence. Particles with a size of −300 + 74 μm can obtain a 96 % Cu recovery in the bubbly flow, while particles with a size of −74 μm lose their separation effect due to hydraulic entrainment.

The role of interfacial nanobubbles in the flotation performance of microfine particles

The enhanced role of Interfacial nanobubbles (INBs) in microfine particles flotation is still unclear. In this study, the microfine particles with different sizes were functionalized to obtain different wettability. The temperature difference method was employed to produce the nanobubbles water. Atomic force microscopy (AFM) was utilized to investigate the formation of INBs. A temperature-controlled flotation system was devised to investigate the flotation performance of microfine particles in the presence and absence of INBs. Agglomeration experiments and attachment time tests were conducted to elucidate the enhanced effects of INBs on flotation from the perspectives of particle-particle and bubble-particle interactions. The results showed that both the number and size of INBs increased with the increase of surface hydrophobicity and level of air saturation in water. In the temperature-controlled flotation system, the flotation recovery and flotation rate of microfine particles were improved significantly in nanobubbles water compared to that in normal water. The optimal flotation result of −38 μm strongly hydrophobic particles was obtained in nanobubbles water at 25 ℃. The enhanced impact of INBs on flotation was more pronounced for more hydrophobic particles. The increase in the apparent size of particles and reduction in particle-bubble attachment time facilitated by INBs contributed to the flotation performance of microfine particles. This study underscores the pivotal effect of INBs on the flotation of microfine particles through enhancing particle-particle and bubble-particle interactions.

Role of oil droplet size on dynamic pore wetting of active carbon and particle-bubble interaction: New inspiration for enhancing the porous mineral floatability

The dynamic pore wetting plays a vital role in the flotation separation process of porous mineral particles, such as low-rank coal, fly ash and chrysocolla, etc. This paper investigated the dynamic pore wetting behavior of active carbon particles in the water-oil emulsion by 1H low-field nuclear magnetic resonance (1H LF-NMR). The influence of oil droplet size on pore wetting process was revealed. The change in the surface properties of particles before and after wetting was analyzed by contact angle and FTIR measurements. The particle-bubble attachment process in the emulsion and pure water was compared. The total pore wetting percentage of active carbon had a first-order kinetic relationship with the wetting time. The emulsion was beneficial to decrease the pore wetting percentage of particles compared with water. And the pore wetting percentage decreased with the decrease of oil droplet size in emulsion. The pores were easily filled by the oil droplet with small size and the hydrophobicity of sample surface was improved, which prevented the subsequent pore wetting by water. As a result, the detachment force of particle-bubble was increased with the help of micro-oil droplets. This work attempts to provide a new inspiration for the study of porous mineral flotation.

Effects of seawater on the adsorption of xanthate onto galena and sphalerite

Seawater contains divalent calcium and magnesium cations. Under alkaline conditions, calcium and magnesium ions react with hydroxide ions to form insoluble hydroxyl complexes or hydroxide precipitates. The hydrophilic substances that may be adsorbed on the mineral surface during the flotation process hinder the adsorption of the collector, affecting mineral hydrophobicity, and thus reducing the floatability of the mineral. In this study, the effects of seawater on the adsorption of xanthate onto galena and sphalerite were investigated. The results show that under strong alkaline conditions, seawater has significant and slight adverse effects on sphalerite and galena, respectively. Flotation regulators such as ethylenediamine tetraacetic acid, sodium hexametaphosphate, and sodium silicate can eliminate the adverse effect on galena and sphalerite flotation to a certain extent. The mechanisms were revealed through microflotation experiments, contact angle measurements, bubble-particle attachment tests, zeta potential measurements, and XPS analysis.

Application and mechanism of an efficient hydrophobic flocculant CPAM in the flocculation reverse flotation of hematite and microfine-grained chlorite

Chlorite is often associated with hematite and tends to form microfine particles during grinding, making it challenging to recover and separate from hematite through flotation. This study innovatively applies an ester-based cationic polyacrylamide (CPAM) as a flocculant in a reverse flotation system using dodecylamine (DDA) as a collector, to flocculate and recover microfine-grained chlorite. The method achieves efficient separation between microfine chlorite and hematite. Laser particle size testing and optical microscopy show that CPAM significantly increases the apparent particle size of microfine chlorite, causing it to aggregate into flocs, while having a extremely weak effect on hematite flocculation. Further analysis using techniques like Zeta potential, contact angle measurement, Fourier-transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) reveals CPAM's stronger adsorption affinity for chlorite compared to hematite. The ester groups in CPAM selectively form hydrogen bonds with chlorite's surface H atoms, enhancing its hydrophobicity. Particle-bubble attachment angle testing confirms that the flocculated chlorite flocs exhibit better floatability and higher efficiency in collision and adhesion with bubbles. Thus, CPAM serves as an efficient flocculant for reverse flotation separation of microfine chlorite and hematite.

Effect of seawater on flotation separation of galena from sphalerite

Magnesium and calcium ions in seawater react with hydroxide ions to generate insoluble hydroxyl complexes or hydroxide precipitates, which affects the floatability of sulfide minerals and causes uncertain effects on flotation separation. In order to ascertain the mechanism of the effects, the flotation separation of lead and zinc in seawater was investigated in this study. Compared with that in DI water, Pb grade in lead concentrate decreased from 59.30% to 53.00%, and galena recovery decreased from 63.47% to 47.79%. The SI decreased from 2.051 to 1.451. The results show that under strong alkaline conditions, seawater has significant adverse effects on the flotation separation. When EDTA, SHMP and SS were added, the SI altered from 1.451 to 1.435, 2.271 and 2.137, respectively. This demonstrates that regulators can eliminate the adverse effect to a certain extent. The mechanisms were revealed through micro-flotation tests, contact angle measurements, bubble-particle attachment tests, zeta potential measurements, XPS analysis and FT-IR analysis.

Study on inhibition mechanisms of detachment of coal particles from oily bubbles in flotation column

The cyclonic microbubble flotation column is an efficient separation equipment in the beneficiation process of metallic and non-metallic minerals. However, the higher detachment rate of coarse particles in the pulp, pulp-froth interfacial zone, and froth zone is an issue that needs to be addressed urgently in column flotation. Compared with traditional air-water bubbles, oily bubbles have higher hydrophobicity, which is beneficial for strengthening the bubble-particle attachment and inhibiting the bubble-particle detachment. Therefore, oily bubbles were introduced into the cyclonic microbubble flotation column to reduce the particle detachment rate. Firstly, an improved cyclonic microbubble flotation column was set up, and traditional air-water bubbles were placed by oily bubbles through the combined use of an atomizer and a bubble generator during experiments. Subsequently, we investigated the feasibility of using oily bubbles as a flotation carrier to regulate the particle detachment rate, improve the particle recovery, and explore the mechanism behind this. Column flotation results showed that recovery rates generated from experiments with oily bubbles are higher than those with air-water bubbles under different operation conditions, and the particle detachment rate in the interfacial region was significantly reduced with the use of oily bubbles. Recoveries and flotation rate constants generated from collection zones for each particle size range indicated that the use of oily bubbles can increase the upper limit of flotation particle size compared with the use of air-water bubbles. Calculated detachment rates showed that the use of oily bubbles can effectively reduce the detachment probability of particles with different sizes in the collection zone. Combined with the observation of ultrasonic-assisted oscillation, it is proved that the oil coating film on the oily bubble significantly improves the resistance of oily bubbles to turbulent disturbance. In addition, the increase in hydrophobic force between oily bubbles and particles and the growth of the three-phase contact periphery are beneficial to reducing the particle detachment probability due to turbulent disturbance in the collection zone. Results from bubble coalescence experiments showed that the existence of oily bubbles significantly reduced bubble coalescence time and increased the damping coefficient. Compared with air-water bubbles, oily bubbles have a stronger damping effect on the oscillation caused by bubble coalescence, inhibiting the violent bubble surface deformation and the induced particle detachment during bubble coalescence. Therefore, the introduction of oily bubbles is a promising idea to reduce the detachment probability of coarse particles and increase the upper limit of particle size in column flotation.

Effect of sodium silicate modified with Fe2+ and Al3+ as dispersant on flotation of molybdenite and chalcopyrite in presence of kaolinite and seawater

Mineral processing is increasingly challenging due to the low grades of ores being processed and the high content of ultra-fine particles, such as clays. Negative effects of the presence of clays on the flotation process include modification of the rheology of slurries, changes in the hydrodynamics of the particle-bubble attachment and slime coating, which reduce the recovery of valuable material. The negative effects have been addressed by using dispersants such as silicates. In this paper, the effect that the presence of silicates modified with Fe2+ and Al3+ has on flotation of molybdenite and chalcopyrite is studied. Microflotation of ores with high content of chalcopyrite and molybdenite were carried out, using kaolinite as ultra-fine particulate system, and conventional and sea water as aqueous medium. Results showed that the effect of modified and unmodified sodium silicates is higher in the flotation of the molybdenite than in the flotation of chalcopyrite. This was corroborated in the measurements of zeta potential in solutions of different ionic charges. The measurements of the zeta potential showed that the addition of sodium silicate modified with Fe2+ maintained the potential in the most negative zone in the different aqueous solutions tested for the case of the chalcopyrite, which would indicate that there is a major repulsion of the precipitates of calcium and magnesium of the surface mineral compared with the measurements in which Al3+ was utilized.

Molecular-level study of hydrophobic interactions during low-rank coal particle-bubble attachment

Particle-bubble attachment is a crucial part of coal and mineral flotation processes. The attachment of two different hydrophobic low-rank coal particles to bubble surface were simulated by a non-equilibrium molecular simulation method. Both particles were subjected to water film drainage resistance when approaching the bubble. Eventually, CPC (low-rank Coal Particle with mixed Collector adhered) jumped in and attached to bubble, but CP (low-rank Coal Particle) had only repulsive effect with bubble. The surface water film of CPC generated tiny hole under the entropy effect of water molecule rearrangement, and the presence of gas–water and oil–water interfacial tension promoted the rapid expansion of the hole until the water film rupture. The critical rupture thickness of the water film on CPC surface was about 1 nm and the rupture was completed in a very short time of 0.4 ns. The CPC jumped in and attached to the bubble surface under the action of oil–water interfacial tension. This suggests that the long-range hydrophobic force originates from the combined action of various interfacial tensions. Our results demonstrate the important role of interfacial tension in the attachment of hydrophobic particle to bubble, and contribute to the connection between microscopic and macroscopic mechanism of particle-bubble attachment.

Effect of particle shape on bubble-particle attachment behavior: Roles of surfaces, edges, and vertexes

It has been understood through many studies that particle shape is important in terms of particle adhesion to air bubbles in flotation. However, there are many questions yet to be answered. Whether the surface of the particle or its sharp corners is effective is only one of the issues that need to be better understood. Therefore, this study aims to delve deeper into the fundamental studies on the role of particle's geometry (surface, edges, and vertex) in their flotation behavior by investigating the attachment of spherical, cylindrical, triangular prismatic, and cubic particles to air bubbles based on their attachment efficiency, settling velocity, collision efficiency, and induction time. Bubble-particle attachment test results inferred that the attachment efficiency was in the order of cubic > triangular > cylindrical > spherical. In addition, it was found that the induction time of the spherical surface decreased from 37 ms to 15 ms with increasing collector concentration, while the induction time of the edged cubic particle decreased from 8 ms to 2 ms. This was attributed to the fact that the edge facilitates the drainage, thinning, and rupture of the water film between the bubble and the particle, thereby increasing the attachment efficiency. Finally, it has also been observed that the three-phase contact line of the cube particle is larger than that of the spherical particle, which improves the attachment stability and reduces detachment efficiency. The results obtained in this study shed light on the fact that the shape of the particles fed to flotation can be produced by using a suitable mill and thus higher flotation efficiency can be achieved with lower collector concentration.

Insight into the influence of surface wettability on flotation properties of solid particles – Critical contact angle in flotation

Bubble-particle attachment is a fundamental element of the flotation process, and its occurrence depends on the stability of the thin liquid film separating these objects. In this study, the effect of surface wettability on the stability of liquid film and subsequent attachment was investigated by flotation of glass microspheres (70–110 μm) with controlled contact angles (9–89°) in a Hallimond tube. Additionally, pH was varied to determine the electrostatic interactions between the bubble and particles. The results showed that for the flotation process to take place, the minimum (critical) value of the contact angle must be exceeded. This value was found to be ca. 25° when the electrostatic interactions were either attractive or weakly repulsive and as high as 62° for strong repulsive electrostatic interactions. These findings highlight the role of attractive hydrophobic interactions, whose importance increases with increasing surface contact angle in the context of stability of thin liquid films.

Correlation of Flotation Recoveries and Bubble–Particle Attachment Time for Dodecyl Ammonium Hydrochloride/Frother/Quartz Flotation System

Recent studies in the flotation of fine particles have necessitated new techniques and analyses for developing various strategies. Particularly, the improvements in flotation chemistry including the selection of the type of frother, collector, and other reagents have become very significant. In this study, the effect of different commercial polypropylene glycol frothers (PPG200, 400, and 600) in the presence of dodecylammonium hydrochloride (DAH) was investigated for their contribution to flotation recoveries and bubble–particle attachment time values of fine quartz minerals. Zeta potential measurements with DAH were also carried out as a function of pH and reagent concentration to justify the effect of collector usage alone on the charge of particles. A linear increase in flotation recoveries against collector concentration, e.g., 7.4% recovery at 1 × 10−5 mol/L DAH and 65.4% recovery at 1 × 10−3 mol/L DAH, was obtained. In this context, the contribution of frothers was particularly important in that a recovery of 15.91% in the absence of the frother and a modest increase to 19.70% was obtained upon the addition of PPG600 at its critical coalescence concentration (CCC) of 3 ppm. Finally, a strong correlation was found between the bubble–particle attachment time and flotation recovery as a function of collector concentration (lowest attachment time vs. highest flotation recovery). The latter correlation is very promising because bubble attachment time leads to various micro-mechanisms in flotation including bubble film thinning, bubble rupture, and induction time, and consequently, frother efficiency in the presence and absence of a collector. As a result, the experimental findings were gathered to achieve a consistent base for further fundamental studies on the application of the synergistic effect of frothers and collectors in the flotation of fine particles.

Interaction Behavior between Coarse and Fine Particles in the Reverse Flotation of Fluorapatite and Dolomite.

The precondition for efficient flotation of middle- to low-grade phosphate ore is the dissociation of apatite from gangue minerals through fine grinding. However, fine gangue minerals, such as dolomite, have a lower hardness and are thus easily overground and converted into slime during the grinding stage. The effect of -10 μm dolomite fines (Dol-10μm) on the flotation of -75 + 25 μm dolomite (Dol-75+25μm) and -75 + 25 μm fluorapatite (FAp-75+25μm) from a detailed mechanism was investigated by microflotation tests, cryo-electron microscopy analysis, contact angle measurements, bubble-particle attachment test, and EDLVO theory. It was found that Dol-10μm significantly reduced the recovery of Dol-75+25μm and FAp-75+25μm. The Dol-10μm particles could decrease the flotation recovery of Dol-75+25μm particles by masking on their surfaces, thus reducing the hydrophobicity of mineral surfaces and preventing them from floating. Furthermore, Dol-10μm particles were easily adsorbed on the FAp-75+25μm surface and could not be effectively floated, which results in fine dolomite being mixed into the concentrate at the bottom of the tank, thereby reducing the selectivity of reverse flotation for phosphate ore. The interaction energy calculation showed that the presence of NaOL led to an attractive interaction force between Dol-10μm and Dol-75+25μm, as well as between Dol-10μm and FAp-75+25μm. As a result, Dol-10μm particles presented a nonselective aggregation with Dol-75+25μm and FAp-75+25μm particles, explaining the phenomenon of "slime coating" and the depressing effect of dolomite fines on phosphate reverse flotation.

Study on the effect of flocculation morphology on the floatability of talc flocs and the adhesion mechanism with air bubbles

This study investigates the impact of floc morphology on flotation by preparing two types of flocs with similar apparent particle sizes but different aggregation degrees through varying the stirring speed. Flotation tests were conducted on the two flocs, revealing that flocs with higher aggregation degrees demonstrated superior floatability and higher flotation rate constants. Fractal dimension and AFM analysis indicated that flocs with higher aggregation degrees exhibited higher fractal dimensions, displaying a more circular and compact overall morphology, as well as a more regular and uniform surface morphology. XPS and contact angle tests showed that, for flocs with comparable particle sizes, an increase in fractal dimension led to increased adsorption of flocculant (PEO) on the surface, accompanied by enhanced hydrophobicity. Further analysis of the induction time for particle-bubble attachment and coverage angle demonstrated that flocs with higher fractal dimensions had shorter induction times and larger coverage angles, indicating faster attachment between flocs and bubbles. These findings suggest that flocs with higher fractal dimensions can acquire greater kinetic energy in a flow field, enabling them to more effectively disrupt the hydration film on the bubble surface and adhere to the bubble surface, thereby enhancing floatability.

Compare graphite flotation and coal flotation in Reflux Flotation Cell

The Reflux Flotation Cell (RFC) has been developed as a game-changing technology to improve fine particle flotation, coarse particle flotation and plant capacity. It has been proved successful for coal flotation. This study compared graphite flotation and coal flotation in the RFC under the operation conditions established for optimizing coal flotation with an objective of extending the RFC to mineral flotation. It was interesting to find that graphite flotation in the RFC produced much lower combustible recovery than coal flotation especially at a high gas flux despite the same surface property and feed size of graphite and coal particles tested. Through the modelling of fluid flow, it was found that the lower combustible recovery from graphite flotation was due to the lower sphericity of graphite particles. The flaky graphite particles promoted a greater dynamic drag force and a greater particle settling velocity compared to coal particles with a greater sphericity. This increased the relative velocity between particles and bubbles in the RFC downcomer, unfavourable for bubble-particle attachment in graphite flotation in the RFC. In addition, a higher gas flux environment in the RFC downcomer produced a higher bubble slip velocity, further increasing the relative velocity between particles and bubbles, exacerbating graphite flotation. Furthermore, the extra gas in the inclined channels pushed more graphite particles to the tailing stream given the higher particle settling velocity. This study indicates a direction of how to optimize graphite flotation in the RFC.

Three-phase contact formation between an air bubble and solid surfaces with different hydrophobicity degrees in liquid

Interactions between gas bubbles and solid particles are crucial in numerous industrial processes, including froth flotation, in which particle-bubble attachment plays a vital role. The process efficiency depends on differences in the surface wettability (i.e., hydrophobicity, expressed by the contact angle) of separated particles. This study aimed to investigate the influence of surface hydrophobicity and zeta potential on the formation of a three-phase contact (TPC) between a single air bubble and planar glass surfaces. Different degrees of hydrophobicity were achieved by esterification with a range of alcohols and time. The interaction between the bubble and surface was monitored using a high-speed camera with a time resolution of 1 ms, allowing for measurements of the time of thin liquid film drainage, time and diameter of TPC formation, TPC line expansion velocity, and dynamic contact angles. The observations suggest that TPC formation occurs when the solid surface has a sufficient degree of hydrophobicity (critical contact angle) and is dependent on the differences in zeta potential values between the air bubble and the solid surface in water. When both surfaces are negatively charged, the limiting value of the water contact angle is ca. 35°, whereas for oppositely charged surfaces, the value slightly decreases to ca. 31°. The results show that increasing surface hydrophobicity enhances the bubble adhesion effectiveness by increasing both the propagation velocity of the TPC perimeter and its size (measured by the diameter of the formed TPC). The article also discusses the mechanism of bubble-solid adhesion in relation to the hydrophobicity and zeta potential of the solid surface based on the obtained results.

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.

Interaction mechanisms between sub-bituminous coal particle and air bubble: Impact of collector adsorption

The interaction between air bubbles and minerals surface plays essential role in mineral froth flotation. In this work, an atomic force microscope (AFM) colloidal probe technique was employed to directly measure the interaction forces between an air bubble and sub-bituminous coal (SBC) particle modified with polar (1-dodecanol)/nonpolar (dodecane) collectors, respectively. And the SBC particle-bubble attachment efficiency measurement was used to verify the AFM force measurement results. The adhesion force was found to be stronger for the air bubble-SBC particle modified with 1-dodecanol, which makes particle-bubble attachment efficiency higher than the dodecane-modified condition. The interaction forces between SBC particles and collectors were determined, and the adsorption behavior of the collector on the coal surface was studied by molecular dynamics (MD) simulation, aiming to reveal the underlying mechanism for the variation of collector-modified SBC particle-bubble interaction force. It was found that 1-dodecanol and SBC have stronger adhesion, which helps it to be more easily adsorbed on the SBC surface. The contact angle test and MD simulation results showed that the hydrophobicity of the SBC surface improved the most after the modification with 1-dodecanol, which in turn finally promoted the interaction between SBC surface and air bubble. This work may offer an interesting strategy for the targeted selection of collectors in the flotation process of SBC.

Surface chemistry and flotation properties of galena and pyrite particles in the presence of xanthate- monothiophosphate- thiocarbamate collectors

In this study, surface chemistry and flotation properties of the gold-bearing galena and pyrite minerals of Menderes region, Izmir, Turkey were investigated with the use of xanthate-thiocarbamate-monothiophosphate collectors. In this context, the micro-flotation experiments, the zeta potential, and bubble-particle attachment time measurements were conducted in the presence of Thiophosphate (Aero S-8045), Xanthate (SIBX), and Thiocarbamate (Aero float MX-505) collectors. In the case of micro-flotation experiments, the MX-505 exhibited higher flotation efficiency for both minerals compared to SIBX and S-8045 collectors. In the case of zeta potential experiments as a function of pH, the galena mineral showed a negative charge at pH 5 and 11, no point of zero charge (pzc) was determined, and the pzc of pyrite was determined as pH≈8. The bubble-particle attachment time experiments performed in the presence of S-8045, SIBX, and MX-505 collectors indicated that the attachment efficiency was 100% in the presence of MX-505 at all dosages and contact times. These results revealed that there was an extraordinarily strong interaction between the galena/pyrite and the air bubbles in the presence of MX-505. The results obtained within this study indicated that galena and pyrite minerals showed inherently low natural floatability which can only be enhanced under specific conditions. In the tests conducted on these minerals, galena mineral showed higher natural floatability compared to pyrite mineral, and collectors produced from thiocarbamates have shown greater effectiveness compared to xanthate and thiophosphate.

Molecular interactions between thiolate collectors and non-ionic frothers in mixed monolayers at the air–water interface using a regular solution theory approach

Dithiophosphate (DTP) is classically used as a co-collector in sulfide mineral flotation to promote hydrophobicity on target particles. Notwithstanding the improved recoveries observed, DTP does not appear to behave as a conventional collector, since it has been shown that it does not adsorb onto certain sulfide mineral surfaces. Recent investigations have nevertheless indicated that when DTP does not adsorb onto the sulfide mineral surface, the presence of a non-ionic frother, such as an alcohol or polyglycol ether, activates a synergistic increase in pulp phase mineral recovery and bubble-particle attachment probability. In this paper, a regular solution approach is used to quantify the interactions between thiolate collectors and non-ionic frothers at the air–water interface, where no other methodology could demonstrate such interactions. Attractive interactions were observed between DTP and frothers, whereas no such interaction was observed between xanthate, a standard base metal sulfide collector. It is suggested that this is the first time that such interactions have been shown for the DTP-frother system and this may represent an important contribution to our understanding of the role of DTP reagents in the flotation process.