Flotation Separation Of Minerals Research Articles

Role of citric acid in selective flotation of limonite from quartz using sodium oleate as collector

The issue that eliminating the negative effects of inevitable ions in the pulp on mineral flotation separation has attracted widespread attention. To achieve the efficient flotation separation of limonite from quartz, citric acid was utilized as a depressant for quartz in this paper. The solubility of limonite was studied using inductively coupled plasma tests (ICP), and the effect of Fe3+ and citric acid on the separation of limonite from quartz under sodium oleate (NaOL) system was investigated using batch flotation tests. The underlying mechanisms were probed through zeta potential measurements, infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), and contact angle detection. It was found that limonite could dissolve a certain number of Fe3+ in the pulp. These Fe3+ adsorbed onto quartz and acted as the active sites to promote the adsorption of NaOL, thereby enhancing quartz flotation evidently and deteriorating the separation of limonite from quartz. Fortunately, citric acid could depress the flotation of iron-activated quartz quite well by covering and desorbing the active sites of Fe3+ and causing the steric hindrance to prohibit the adsorption of NaOL. Meanwhile, the hydrophilic groups in citric acid could also increase the surface hydrophilicity of quartz and enhance the inhibitory effect. In comparison, Fe3+ and citric acid had little effect on the adsorption of NaOL onto limonite since its surface exposed enough Fe-active sites for the adsorption of NaOL. Thus, the difference in the floatability of limonite and quartz was enlarged, eventually achieving a better separation of them. This research sheds new light on the role of citric acid in the selective separation of quartz from soluble iron minerals.

Electrochemical action on the flotation beneficiation of ordinary iron ore concentrate

One of the main challenges in processing fresh ferruginous quartzites is to obtain high-quality iron ore concentrates containing more than 70% total iron and less than 1.8% silica to produce DR pellets and hot Briquetted Iron (HBI). Currently, it is widely recognized that the most effective methods to achieve high-quality iron ore concentrates is through reverse flotation using cationic amine collectors in an alkaline medium. However, due to the very fine impregnation of magnetite in quartz, the insufficiently complete release of magnetite even with fine grinding, and the proximity of the flotation (surface) behavior of the separated minerals, high-quality concentrates are not always achievable in the flotation process. Consequently, exploring methods to enhance the efficiency of flotation separation of minerals and improve concentrate quality remains a pertinent issue. Historical studies have shown that electrochemical treatment can adjust the properties of reagents, enhance their effect on specific minerals, and thus control the flotation process. The efficiency of quartz and other silicates flotation by amines significantly depends on the ratio of ionic and molecular forms of the reagent in aqueous solutions of the collector and in the flotation pulp. Altering this ratio can impact the outcomes of reverse cationic flotation of iron ores. It is feasible to change the ratio of the amine forms through electrochemical oxidation or reduction of the reagent solution. Moreover, the electrochemical treatment facilitates the dispersion of the amine in the aqueous medium and its physical adsorption on minerals. Therefore, electrochemical pretreatment of amines can be considered a promising method for intensifying the reverse flotation of iron ore. This paper presents research results aimed at improving the quality of the oversize of the fine screening of ordinary magnetite concentrate from Mikhailovsky GOK, named after A.V. Varichev, through the use of electrochemically treated solutions of cationic amine class collectors in the process of reverse cationic flotation. The research findings confirmed the feasibility of using preliminary diaphragmless electrochemical treatment of reagents Tomamine RA-14 and Lilaflot 811M (esters of monoamine of different composition) for the targeted modification of their properties and for increasing the efficiency of reverse flotation. Consequently, the silica content in the flotation cell product decreased from 1.66–1.7% to 1.51–1.56, with the grade of total iron exceeding 70%.

Quantitative competitive adsorption characteristics of sodium humate and dodecylamine on hematite and quartz surfaces

Competitive adsorption behavior of reagents is of great significance for efficient flotation separation of minerals. Motivated by the surface complex adsorption, surface complexation model (SCM) is an effective approach for quantitative characterization of reagents adsorption behavior. In this study, sodium humate (SH) adsorption and mixed SH and dodecylamine (DDA) competitive adsorption mechanisms onto hematite and quartz were quantitatively described and predicted using SCM. The model simulation suggested that there are two binding forms (monodentate and bidentate) between the groups on SH and the hematite sites and one (monodentate) with the quartz sites. The adsorption equilibrium constants (logK) of SH were calculated, which are 10.15, 23.34 (for hematite) and 10.41 (for quartz), respectively. In addition, the fitting results indicate that SH is adsorbed on the hematite surface mainly through the bidentate ≡Fe2-R(COO)2 site. Furthermore, the successful prediction of adsorption and surface potential at pH system were performed to verify the reliability of the model. Quantitative analysis of mixed SH and DDA interactions with mineral surfaces will elucidate and predict the reagents competitive adsorption behavior, which can also provide reliable data and parameters for surface complexation databases for surface complexation. Meanwhile, this finding provides valuable insights for the flotation of minerals, which enables their selective separation efficiency to be modulated and optimized.

Understanding the anisotropic wettability of spodumene from direct force measurement using AFM and density functional theory calculations

Wettability directly reflects the interaction between minerals, reagents, and water, and is a key factor determining the flotation separation of minerals. Wettability differences of the spodumene anisotropic crystal surfaces are investigated in this study using contact angle relaxation, atomic force microscopy (AFM), and density functional theory (DFT) calculations. The contact angle relaxation and AFM tests confirm the anisotropic wettability of spodumene surfaces from macro and micro perspectives, respectively, and the order of hydrophilicity is (010) > (100) > (110). The DFT calculations based on surface fracture key points and broken bond density explain the differences in the wettability of spodumene crystal surfaces, that is, the types of broken bonds and the number of broken bonds per unit area are the main influencing factors. The wettability of water molecules on different crystal surfaces is simulated based on the DFT calculations of the broken surface bonds and surface energy, which further verifies the experimental results.

Flotation and adsorption of novel Gemini decyl-bishydroxamic acid on bastnaesite: Experiments and density functional theory calculations

Rare earth element is an important strategic metal, but the supply of high purity rare earth ores is growing slowly, which is in sharp contradiction with the rapidly growing demand. Froth flotation has been confirmed to be an effective method to separate bastnaesite from its gangue minerls. However, the traditional collectors are facing serious problems in flotation separation of minerals, requiring the addition of excess depressant and regulator in the flotation process. Herein, we proposed and synthesized novel Gemini hydroxamic acids Octyl-bishydroxamic acid (OTBHA), Decyl-bishydroxamic acid (DCBHA) and Dodecyl-bishydroxamic acid (DDBHA) as the collectors in bastnaesite-barite flotation system. The effect of different carbon chain lengths on the molecular properties were explored by density functional theory (DFT) calculations. DCBHA possessed a stronger reactivity compared with OCBHA and DDBHA. The flotation results verified the consistency of the computational calculation about the performance prediction of Gemini hydroxamic acids. Compared with OCBHA and DDBHA, DCBHA displayed superior collecting affinity toward bastnaesite, and did not float barite. Zeta potential results showed that the presence of DCBHA increased the potential of bastnaesite, while it had almost no effect on barite, indicating DCBHA had a stronger affinity for bastnaesite. Then, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated that the adsorption mechanism was due to two hydroxamate groups of DCBHA co-anchored on bastnaesite surface by forming five-membered hydroxamic―(O―O)―Ce complexes. In addition, atomic force microscopy (AFM) clearly observed that DCBHA uniformly aggregated on bastnaesite surface, which increased surface contact angle and improved the hydrophobicity of bastnaesite.

Mechanical activation mechanism of cassiterite based on copper-based grinding media

During grinding, the abrasion and corrosion of the grinding media generate metal ions, thereby affecting mineral flotation separation. In this study, the mechanical activation mechanism of cassiterite by copper-based media was investigated via grinding and micro-flotation experiments, inductively coupled plasma optical emission spectroscopy (ICP-OES), solution chemistry calculations, X-ray photoelectron spectroscopy (XPS) and Density functional theory (DFT). Compared with ceramic medium, copper-based medium enhanced the grinding technical efficiency of cassiterite and improved the flotation recovery. Mechanism study revealed that the increase Cu ions content in the pulp of cassiterite grinding products was the main contributor to the mechanical activation of cassiterite by copper-based grinding media, and the main forms of Cu in the solution were Cu2+, Cu(OH)+ and Cu(OH)2. XPS results demonstrated that the Cu components adsorbed on the surface of cassiterite as Cu(II) and Cu–O groups. Meanwhile, DFT calculation results shown that the Cu components were spontaneously adsorbed on the surface of cassiterite (110) in the following order: CuOH+ < Cu(OH)2 < Cu2+. Therefore, the adsorption capacity of BHA increased. These results indicate an improvement in the flotation behavior of cassiterite mechanically activated by copper-based grinding media.

Hydrodynamics intensification and interface control in the flotation conditioning process using fractal impellers

Flotation conditioning, an essential part affecting the function of flotation reagent and flotation performance, has gradually become a key field for the process enhancement of flotation. A fractal impeller device was proposed in this paper for use in pre-flotation pulp conditioning. The flow field characteristics and relevant effects on the liquid–solid mixing performance were investigated by the numerical simulation of computational fluid dynamics. The outcome of particle surface modification was assessed by studying changes in the contact angle and zeta potential of diaspore particles. These results showed that the increase of turbulent kinetic energy induced by the fractal impeller improved the dispersion of mineral particles. Meanwhile, the strong turbulence and high shear induced by the fractal impeller provided favorable conditions for collector adsorption and particle modification, leading to the increase in contact angle under relatively higher energy input. This work introduced a kind of novel fractal impellers used in the flotation conditioning to strengthen the flotation separation of minerals.

Synergistic Adsorption and Molecular Arrangement of Mixed Surfactants at the Air/Water Interface

The self-assembly of mixed surfactants at the air/water interface plays a crucial role in mineral flotation separation. This study aimed to investigate the molecular arrangement and synergistic adsorption of mixed surfactants at the air/water interface using molecular dynamics (MD) simulation and surface tension measurement. The stability of mixed surfactant solutions was also measured using dynamic light scattering and ζ potential. We investigated the mixture of octylhydroxamic acid (OHA) and dodecanol (DOD) surfactants at different weight ratios. The surface activity of the OHA/DOD mixture was characterized in detail, including the relative concentration distribution, structural properties, and radial distribution function. The MD simulations revealed that OHA/DOD was inserted into the water as a headgroup at the air/water interface, and the carbon chain extended into the air. A strong synergistic effect was observed between the two surfactants, and a dense monolayer film was formed at the air/water interface, demonstrating higher surface activity. With an increase in the DOD ratio, the hydrogen bond between the OHA headgroup and water molecules became stronger. The order of surface activity of the mixture was OHA:DOD = 1:1 > OHA:DOD = 2:1 > OHA:DOD = 4:1. In the temperature range from 24 to 30 °C, the surface tension decreased and the critical micelle concentration increased with increasing temperature. The addition of DOD changed the conformation of the mixed surfactants, which was beneficial to the aggregation of OHA/DOD complexes. When OHA:DOD = 1:1, the average particle size was the largest and the formed micelles were the most stable. The experimental results are consistent with the surface tension and simulation results.

Using pectin to separate talc and molybdenite through the surface modification with Cu2+: Applications and mechanism

Organic depressants have low selectivity in separating molybdenite and talc because their metal sites lack activity for organics chemisorption. In this study, surface modification by copper sulfate was used to induce the differential adsorption of pectin onto molybdenite and talc surfaces for enhanced flotation separation. Contact-angle experiments, scanning electron microscopy, adsorption measurements, time-of-flight secondary-ion mass spectrometry, and X-ray photoelectron spectroscopy analyses were conducted to reveal the interaction mechanism. Results illustrated that molybdenite and talc could not be separated using pectin alone, while molybdenite was selectively depressed after surface modification by copper sulfate and this effect was strengthened under alkaline conditions. Metal sites (Mg, Si and Mo) of talc and molybdenite themselves were unable to react with pectin, whereas Cu+ would deposit and further function as active site for pectin chemisorption after surface modification. However, the quantity of deposited Cu sites dropped on talc surface and increased on molybdenite surface with increased pH, and the Mo atoms of molybdenite crystal were activated to take part in pectin chemisorption. Therefore, more pectin was adhered on molybdenite surface, which imparted molybdenite stronger wettability. Herein, surface-modification through metal ions can enable the differential adsorption of organic depressants and enhance the flotation separation of minerals.

Flotation separation of chalcopyrite and pyrite via Fenton oxidation modification in a low alkaline acid mine drainage (AMD) system

The selective flotation separation of pyrite and chalcopyrite, and the comprehensive utilization of AMD play a vital role in the cleaner production of copper sulfide ore. In this paper, flotation separation of chalcopyrite and pyrite via Fenton oxidation modification in a low alkaline acid mine drainage (AMD) system was investigated. The results of micro-flotation experiment displayed that the maximum recovery difference between chalcopyrite and pyrite was 74.6% at recommended test conditions. The artificial mixed-mineral flotation experiment further confirmed the desirable flotation separation of minerals. Zeta potential, FTIR spectra analysis, contact angle measurement and adsorption amount analysis results confirmed that the hydrophilic species caused by Fenton oxidation could seriously hinder the interaction between pyrite surfaces and EX collector. Whereas, the Fenton oxidation had feeble influence on the floatability of chalcopyrite. The XPS study indicated that Fenton oxidation significantly increased the contents of SO42- on pyrite surfaces, and the concentration of SO42- increased from 5.9% to 37.65%. Meanwhile, this modification promoted the deep transformation of Fe chemical states mainly from Fe(Ⅱ)-S to Fe(III)–OOH and Fe2(SO4)3. As a result, the contents of Fe(III)–OOH and Fe2(SO4)3 reached 50.04% and 29.19%, respectively. For chalcopyrite, a small amount of oxide/hydroxide species were formed during this processing, and the chalcopyrite can interact with EX collector effectively. Thus, flotation separation of chalcopyrite and pyrite via Fenton oxidation modification in a low alkaline AMD system mainly attributes to the significant differences in the number and species of hydrophilic species.

Study on the influence of particle size on the flotation separation of kaolinite and quartz

The influences of particle size on the flotation separation of kaolinite and quartz was explored by flotation tests of full-size and various sizes, zeta potential analysis. The flotation separation effects of kaolinite and quartz mixed minerals under different conditions were analyzed by calculating the characteristic parameters such as K, R ∞ , Km, SI and SE. Results show that in the sodium oleate scenario, kaolinite has better floatability under neutral conditions, while quartz has better floatability at pH 12. Ca 2+ has little effect on the floatability of kaolinite but it does inhibit the floatability of quartz under acid and weak alkali conditions. As well it can improve the floatability of quartz at a pH 12. In the two mineral flotation separation tests, reverse flotation had better selectivity for coarse-grained minerals. The maximum separation efficiency of the mixed ore with a particle size of 0.125–0.075 mm was 71.88%, the recovery of kaolinite in the concentrate was 84.97%, and the recovery of quartz amounted to 13.10%. It is of great significance to the research on the flotation separation of kaolinite and the high resource utilization of kaolinite. • 0.250–0.030 mm can be separated through positive and reverse flotation. • −0.030 mm fine kaolinite and quartz can't be separated by sodium oleate flotation. • When pH is less than 8, Ca 2+ is conducive to positive flotation separation. • Conforms the first kinetic model, reverse flotation has high separation efficiency.

Interaction of a novel depressant m-nitrobenzoate with arsenopyrite surface: DFT and experimental studies

The selective interaction of reagents with mineral surfaces is the core basis for mineral flotation separation. Herein, the interaction mechanism of a novel depressant m-nitrobenzoate with arsenopyrite has been investigated with the help of density functional theory (DFT) simulations, supplemented by micro-flotation tests and X-ray photoelectron spectroscopy (XPS) analyses. It is found that the adsorption of m-nitrobenzoate on the surface of arsenopyrite was mainly due to the effect of –NOO– in m-nitrobenzoate. These findings provide a clear correlation between the experiments and DFT, indicating that the –NOO– in m-nitrobenzoate can adsorb on the surface of arsenopyrite via a covalent bond, thereby realizing the depress of arsenopyrite.

Interaction between hydrocarbon oil and hydrophilic mineral surfaces: A chemical force microscopy and molecular dynamics simulation study

Hydrocarbon oil collectors are typically used in the mineral flotation process to increase the hydrophobicity of the mineral surface. However, the mechanism of action of hydrocarbon oil on hydrophilic mineral surfaces remains unclear. This study innovatively applied chemical force microscopy (CFM) and molecular dynamics (MD) simulations to study the interactions between hydrocarbon oil and hydrophilic mineral surfaces. The CFM results showed that the interactions between RCH3, ROH, RCOOH, and RNH4+ and the hydrophilic mineral surface are always repulsive, and can be well described by Derjaguin–Landau–Verwey–Overbeek theory, which considers both van der Waals and electrostatic forces. The type of functional group significantly influenced the adhesion force between the hydrocarbon oil collector and hydrophilic mineral surface, and the adhesion forces followed the order RNH4+ > ROH > RCOOH > RCH3, indicating that polar hydrocarbon oil molecules adhered strongly to the hydrophilic mineral surface, whereas nonpolar hydrocarbon oil molecules did not adhere to this surface. MD simulation results showed that polar micro-oil droplets easily spread on the hydrophilic surface, while nonpolar micro-oil droplets were difficult to spread. Hydrophilic mineral surfaces preferentially attract water molecules and repel hydrophobic hydrocarbon oils, which reduces the adsorption energy of nonpolar hydrocarbon oils. Polar hydrocarbon oil is an effective collector for increasing the surface hydrophobicity of hydrophilic minerals. The combination of MD and CFM illustrated the mechanism of action of hydrocarbon oil collector molecules, which provides a theoretical reference for mineral flotation separation.

The interaction of flotation reagents with metal ions in mineral surfaces: A perspective from coordination chemistry

The selective interaction between reagents and mineral surfaces is the core basis of mineral flotation separation. This paper creatively proposes a perspective from coordination chemistry to clarify the interaction mechanism of reagents with mineral surfaces systematically and profoundly. The metal ion in mineral surface is far different from the free ion. The former is in a semi-constrained state, causing the properties of surface metal ions to be greatly affected by surface structures and properties of surrounding atoms. Based on coordination chemistry, the π-backbonding model is advanced for the interaction between sulfhydryl collectors and sulphide minerals. It is of interest that with more π electron pairs, the surface metal ion is more likely to interact with sulfhydryl collectors containing unoccupied π orbitals; with greater polarizability, the metal ion is more prone to covalent interactions with sulfhydryl collectors. In addition, the unoccupied orbitals play a crucial role in selectivity of depressants. For example, the depressants NaCN and Ca(OH)+ containing unoccupied π orbitals can strongly depress pyrite holding π electron pairs, but can hardly depress galena possessing no π electron pair. Furthermore, the crystal field stabilization energy resulting from the interaction between reagents and surface metal ions can influence the stability of reagent adsorption, and can adequately explain the order of flotation critical pH for sulphide minerals. The coordination theory sheds new light on the interaction mechanism between flotation reagents and mineral surfaces.

Interaction mechanism of organic carboxylate with kaolinite and montmorillonite: A density functional theory study

The covering of aimed minerals by kaolinite and montmorillonite is an important factor leading to poor flotation selectivity. Organic inhibitors with small molecular weights can significantly improve this phenomenon. We selected nine kinds of organic carboxylate inhibitors with small molecules, and the stable adsorption conformations and adsorption energy of nine kinds of carboxylate ions on kaolinite (0 0 1) and montmorillonite Na (0 0 1) surfaces were obtained using DFT calculations. We found that the hydrogen phthalate ion has the strongest interaction with both the kaolinite and montmorillonite surfaces. Finally, a mixed system of acetate-kaolinite (0 0 1) surface and acetate-montmorillonite Na (0 0 1) surface were constructed, and the bond populations between the acetic acid and mineral surface and the atomic Mulliken charges were calculated. The interaction mechanism of small molecular organic carboxylates with kaolinite and montmorillonite were explained directly at the atomic and electronic levels. This work might shed new light on the flotation separation of minerals associated with kaolinite and montmorillonite under the condition of small molecular organic carboxylates as inhibitor. And it provides with a reliable method to select inhibitors before flotation.

The role of surface roughness in the wettability and floatability of quartz particles

Surface roughness affects both the adsorption capacity of collector and mineral flotation separation. To investigate the role of surface roughness in quartz flotation, in this study, quartz particles were ground by different mills to produce two quartz samples with different nano-sized roughness, which was quantified with atomic force microscopy (AFM). Flotation experiments were carried out using CaCl2 as an activator and sodium oleate (NaOL) as a collector. The results of flotation experiments showed an excellent performance with high recoveries for the rough quartz particles in contrast to the case with the smooth ones. Surface chemical aspects for the role of surface roughness in flotation were investigated through measurements of X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscope-Energy Dispersive Spectrometry (SEM-EDS), collector adsorption capacity and contact angle analysis. Both XPS and SEM-EDS results demonstrated larger adsorption capacity of Ca2+ for the rough quartz particles due to more adsorption sites provided by larger specific surface area. The NaOL adsorption capacity results also confirmed that larger surface roughness corresponded to higher adsorption capacity of NaOL. Subsequently, the contact angle results revealed that after interacting with NaOL the rough quartz particles presented more hydrophobic. Combined with flotation tests and surface chemical analysis, it might be arrived that surface roughness affected the adsorption capacity of both Ca2+ and NaOL, therefore impacting the wettability and floatability of quartz particles.

Role of mineral flotation technology in improving bitumen extraction from mined Athabasca oil sands: I. Flotation chemistry of water‐based oil sand extraction

AbstractThe role of surface hydrophobicity in water‐based oil sand extraction is examined from the perspective of mineral flotation separation. Although anionic carboxylates (sulphonates) released from bitumen are helpful for charging bitumen and liberating bitumen from sand grains, their presence in oil sand slurries tends to make bitumen and bubbles less hydrophobic. In addition, solid hydrophobization under oil sand extraction conditions can occur through different mechanisms of carboxylate adsorption. It is the hydrophobized fine solids that present challenges for achieving a high bitumen recovery with a good froth quality, due to their competition with bitumen for attachment to bubbles. While chemisorption of carboxylates contributes to hydrophobization of heavy minerals present in oil sands, carboxylate adsorption activated by hydrolyzed metal cations alters silica and clays from hydrophilic to hydrophobic. Different adsorption mechanisms of calcium on silica, clays, and other minerals are analyzed to explain why fine solids of varying mineralogy in combination with calcium affect bitumen extraction differently. Metal ions that activate solid hydrophobization under oil sand extraction conditions are identified from dynamic attachment of solids from mature fine tailings (MFT) to bitumen. To mitigate the effect of fines on oil sand extraction, selective flocculation of fine solids is recognized as especially feasible for bitumen flotation recovery from oil sand middling streams. Future research in reducing or eliminating caustic addition, understanding the role of inorganic anions, and searching for feasible techniques for treating MFT based on different mineralogy and surface properties, are briefly discussed.

Depressing effect of fine hydrophilic particles on magnesite reverse flotation

The influence of fine particles on the flotation separation of minerals is becoming increasingly important as new, fine grained deposits are exploited. Fine particles float poorly and less selectively under normal flotation conditions, having detrimental effects on recovery of other minerals. The reasons of this interacting effect are complex, which may be entrainment, pH variation, dissolved ions from mineral surfaces, aggregation/dispersion and coating behavior of particles or even the competitive adsorption effect. In this study, the influence of fine magnesite and dolomite on the flotation of quartz was investigated. It was found that at pH=9.2–9.5 and with DDA dosage of 8.6×10−4, the recovery of coarse (−100+65μm) quartz was reduced dramatically from 96.66% to 37.15% when the content of quartz was 5% in the flotation with fine (−5μm) magnesite, and when the content of fine dolomite was increased from 2.5% to 20%, the recovery of coarse quartz was reduced from 91.20% to 75.08%. To examine the reasons, zeta potential, zero point of charge and contact angles of magnesite, dolomite and quartz were measured in the absence and presence of dodecylamine (DDA). The interaction energies between particles were then calculated. Results showed that the aggregation behavior of mineral particles was likely to be the reason. Interaction energy calculated based on Extended-DLVO (Derjaguin–Landau–Verwey–Overbeek) theory predicted that in DDA surfactant solution, the interaction forces between magnesite and quartz, dolomite and quartz were attractive, between dolomite and magnesite was repulsive. The experimental results are in excellent agreement with the theoretically predicted results. The aggregation caused by interacting behavior explains the depressing effect of fine hydrophilic particles on magnesite reverse flotation.

Influence of mineral compositions and their modification on the selection flowchart and collectors of selective flotation of ores of nonferrous metals

The influence of the mineral composition of sulfides and their modifications on the selection of flowcharts for the selective flotation of ores of nonferrous metals is considered. It is shown that the oxidation conditions of collectors with the formation of a new form of the collector participating in the formation of sorption layers on the surface play a significant role in the mechanism of the interaction of the collector with minerals. Practical investigations showed that the application of combinations of compositions of various collectors allow us to increase their collection and selective properties and improve the efficiency of the flotation separation of minerals. It is revealed that the structure of the adsorption layer with the use of the composition of the collectors in the flotation (one of them is the xanthate) is determined by the ratio of components and sequence of their dosing. These results allowed us to change the flowcharts of flotation of the ores of the Tarnier, Gai, and other deposits with the recovery of modifications of pyrite and sphalerite relative to the stages of the flotation process.

Selection of selective collectors for flotation of minerals with similar flotation properties

A computational method for selecting collectors to investigate the flotation separation of minerals using the principle of hard and soft acids and bases (the Pearson principle) is presented with the examples of sulfide and calcium-containing minerals. Calculated data on the absolute hardness and electronegativity of cations of heavy metals (copper, iron, zinc, and lead) and calcium, solid acids, and ionogenic and nonionic collectors, as well as on the charge transfer in a conjugated “acid-base” pair, are presented. Nonionic low-polar compounds are potentially able to additionally increase the distinctions in the structure of the adsorption layer of collectors on the separated minerals. According to the degree of charge transfer in the conjugated acid (metal cation)-base (collector) pair, the calculated results are correlated with experimental results (non-frothing flotation, adsorption, and IR spectroscopy).