Special Issue "Flotation Chemistry"

A special issue of Minerals (ISSN 2075-163X).

Deadline for manuscript submissions: closed (31 January 2018)

Special Issue Editors

Guest Editor
Prof. Dr. Yuehua Hu

School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
Website | E-Mail
Interests: minerals processing; crystal chemistry of minerals; solution chemistry of flotation; electrochemistry of flotation; wastewater treatment
Guest Editor
Dr. Zhiyong Gao

School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
Website | E-Mail
Interests: flotation of oxide minerals; mineral crystal chemistry; flotation reagent molecular design; mineral/reagent/water interfacial science; waste treatment in minerals processing

Special Issue Information

Dear Colleagues,

We invite contributions to this Special Issue on aspects listed in the keywords, covering recent advances and innovations in flotation chemistry, which will be of direct interest to researchers and practitioners in the mineral processing field. Contributions reporting on mineral surface chemistry, the development and design of novel reagents, and mechanism exploration of mineral/reagent interactions using advanced tools and instruments, are especially welcome.

Keywords

  • Minerals (sulfide oxides, silicates, sparingly soluble minerals, iron minerals, rare earth minerals, etc.)
  • Mineral chemistry (surface reactivity, surface broken bonds, surface energy, wettability, surface hydration, surface charge, etc.)
  • Reagents (collectors, depressants, dispersants, etc.)
  • Reagent chemistry (QSAR, molecular design, assembly, etc.)
  • Mineral/reagent interaction (molecular dynamics simulation, quantum chemistry simulation, AFM, XPS, QCM-D, SFG, etc.)
  • Flotation

Dr. Zhiyong Gao
Prof. Yuehua Hu
Guest Editors

Manuscript Submission Information

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Keywords

  • Minerals (sulfide oxides, silicates, sparingly soluble minerals, iron minerals, rare earth minerals, etc.)
  • Mineral chemistry (surface reactivity, surface broken bonds, surface energy, wettability, surface hydration, surface charge, etc.)
  • Reagents (collectors, depressants, dispersants, etc.)
  • Reagent chemistry (QSAR, molecular design, assembly, etc.)
  • Mineral/reagent interaction (molecular dynamics simulation, quantum chemistry simulation, AFM, XPS, QCM-D, SFG, etc.)
  • Flotation

Published Papers (20 papers)

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Open AccessArticle
Effect of Sodium Sulfite on Floatability of Chalcopyrite and Molybdenite
Minerals 2018, 8(4), 172; https://doi.org/10.3390/min8040172
Received: 14 March 2018 / Revised: 15 April 2018 / Accepted: 16 April 2018 / Published: 22 April 2018
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Abstract
Sodium hydrogen sulfide (NaHS) is commonly used as a copper depressant in the selective flotation of copper and molybdenum ores. However, the process is facing health and safety issues because NaHS readily yields toxic hydrogen sulfide gas (H2S) under acidic conditions. [...] Read more.
Sodium hydrogen sulfide (NaHS) is commonly used as a copper depressant in the selective flotation of copper and molybdenum ores. However, the process is facing health and safety issues because NaHS readily yields toxic hydrogen sulfide gas (H2S) under acidic conditions. In this study, Na2SO3 was proposed as an alternative copper depressant. The effect of Na2SO3 on the surface wettability and floatability of chalcopyrite and molybdenite—typical copper and molybdenum minerals, respectively—was intensively studied using contact angle measurements and flotation tests. Contact angle readings show that the chalcopyrite surface became hydrophilic after the Na2SO3 treatment. Meanwhile, the molybdenite surface was relatively more hydrophobic compared with that of chalcopyrite after the treatment. Flotation tests using pure minerals of chalcopyrite and molybdenite demonstrate that the floatability of chalcopyrite decreased with increasing concentration of Na2SO3. On the other hand, the floatability of molybdenite gradually increased under similar conditions, suggesting that Na2SO3 might have the potential to be used for selective flotation of chalcopyrite and molybdenite. A possible mechanism is proposed in this study to explain the phenomenon using X-ray photoelectron spectroscopy analysis. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
An Insight into Flotation Chemistry of Pyrite with Isomeric Xanthates: A Combined Experimental and Computational Study
Minerals 2018, 8(4), 166; https://doi.org/10.3390/min8040166
Received: 26 March 2018 / Revised: 12 April 2018 / Accepted: 16 April 2018 / Published: 19 April 2018
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Abstract
The flotation chemistry between pyrite and isomeric xanthates (butyl xanthate and isobutyl xanthate) was investigated by means of adsorption experiments, surface tension tests, and molecular dynamic simulations in this work. The flotation chemical results were confirmed and further interpreted by quantum chemical calculations. [...] Read more.
The flotation chemistry between pyrite and isomeric xanthates (butyl xanthate and isobutyl xanthate) was investigated by means of adsorption experiments, surface tension tests, and molecular dynamic simulations in this work. The flotation chemical results were confirmed and further interpreted by quantum chemical calculations. The experiment results demonstrated that the isobutyl xanthate exhibited superior adsorption capacity and surface activity than those of butyl xanthate in flotation chemistry. In addition, molecular dynamic simulations were simultaneously performed in constant number, constant volume and temperature (NVT), and constant number, constant volume, and pressure (NPT) ensemble, indicating that the NPT ensemble was more suitable to the flotation system and the isobutyl xanthate was easier to be adsorbed on pyrite surface compared with butyl xanthate during an appropriate range of concentrations. Furthermore, the quantum chemical calculations elucidated that the isobutyl xanthate presented higher reactivity than that of the corresponding butyl xanthate based on the frontier molecular orbital theory of chemical reactivity, which was consistent with experimental and simulation results obtained. This work can provide theoretical guidance for an in-depth study of the flotation chemistry of pyrite with isomeric xanthates. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Performance Analysis of Thiocarbonohydrazide as a Novel Selective Depressant for Chalcopyrite in Molybdenite-Chalcopyrite Separation
Minerals 2018, 8(4), 142; https://doi.org/10.3390/min8040142
Received: 15 February 2018 / Revised: 16 March 2018 / Accepted: 16 March 2018 / Published: 2 April 2018
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Abstract
A novel surfactant, thiocarbonohydrazide (TCH), was synthesized and tested for the first time as a selective chalcopyrite depressant in Cu-Mo separation. Its adsorption mechanisms on chalcopyrite were studied by flotation tests, zeta potential, FTIR, XPS and ToF-SIMS measurements. FTIR and zeta potential analyses [...] Read more.
A novel surfactant, thiocarbonohydrazide (TCH), was synthesized and tested for the first time as a selective chalcopyrite depressant in Cu-Mo separation. Its adsorption mechanisms on chalcopyrite were studied by flotation tests, zeta potential, FTIR, XPS and ToF-SIMS measurements. FTIR and zeta potential analyses suggested that there was a strong chemisorption reaction between TCH and chalcopyrite, resulting in the formation of TCH–copper complexes. XPS and ToF-SIMS measurements further confirmed the chemisorption of TCH onto the chalcopyrite surface and showed that this chemisorption reaction is due to its S and N atoms, which form five-membered chelating rings by releasing H ions. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Influence of Particle Size in Talc Suppression by a Galactomannan Depressant
Minerals 2018, 8(4), 122; https://doi.org/10.3390/min8040122
Received: 28 January 2018 / Revised: 14 March 2018 / Accepted: 16 March 2018 / Published: 21 March 2018
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Abstract
Flotation behavior of different sizes of particles may follow different trends. The influence of particle size in talc suppression by a depressant galactomannan was studied in this research. The flotation response and mechanism were examined by flotation tests, modified flotation rate constant and [...] Read more.
Flotation behavior of different sizes of particles may follow different trends. The influence of particle size in talc suppression by a depressant galactomannan was studied in this research. The flotation response and mechanism were examined by flotation tests, modified flotation rate constant and entrainment recovery calculation, laser particle size experiments, adsorption tests, and advancing contact angle measurement as well as scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The maximum recovery increased with particle size increases in the absence of galactomannan FPY (Fenugreek polysaccharide). The obviously suppressed effect was observed for the size fraction of −74 + 38 μm after reacting with FPY, but low efficiency was received for −38 μm and −10 μm, respectively. Laser particle size analysis indicated that the FPY has a certain function for the flocculation of fine particles. It is beneficial for reducing recovery by entrainment. EDS and advancing contact angle test results showed that the difference in contact angles probably is a result of genuine differences in the quantity of O and Mg bearing surface species, while the contact angle varied with particle size fraction in the absence of FPY. Adsorption and SEM test results demonstrated that in the case of −74 + 38 μm, the depressant adsorption density on the mineral surface is higher than the other two size fractions. On the whole, FPY probably is not enough of a depressant for talc suppression. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Fundamental Flotation Behaviors of Chalcopyrite and Galena Using O-Isopropyl-N-Ethyl Thionocarbamate as a Collector
Minerals 2018, 8(3), 115; https://doi.org/10.3390/min8030115
Received: 31 January 2018 / Revised: 8 March 2018 / Accepted: 12 March 2018 / Published: 13 March 2018
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Abstract
Copper and lead are two important and widely used metals in industry. Chalcopyrite (CuFeS2) is associated with galena (PbS) in ore, and it has been a research hotspot in separating galena from chalcopyrite by flotation. In this study, the flotation behaviors [...] Read more.
Copper and lead are two important and widely used metals in industry. Chalcopyrite (CuFeS2) is associated with galena (PbS) in ore, and it has been a research hotspot in separating galena from chalcopyrite by flotation. In this study, the flotation behaviors of chalcopyrite and galena were studied through flotation tests, adsorption measurements, solution chemistry calculation, Fourier transform infrared spectroscopy (FTIR) and molecular dynamics (MD) simulations. The results show that the floatability of chalcopyrite is better than that of galena in the presence of O-isopropyl-N-ethyl thionocarbamate (IPETC), and the recovery difference between chalcopyrite and galena is about 20% when IPETC is 7 × 10−4 mol/L at pH 9.5, while the floatability difference between the two minerals is significant. Competitive adsorption of OH and IPETC on mineral surfaces leads to lower floatability of galena than that of chalcopyrite. IPETC is able to remove the hydration layer on mineral surfaces and then adsorb on active sites. The floatability of minerals is enhanced with the increase of their hydrophobicity. This study provides a reference to separate galena from chalcopyrite. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Selective Attachment of Leptospirillum ferrooxidans for Separation of Chalcopyrite and Pyrite through Bio-Flotation
Minerals 2018, 8(3), 86; https://doi.org/10.3390/min8030086
Received: 31 January 2018 / Accepted: 1 February 2018 / Published: 27 February 2018
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Abstract
The replacement of depressants used in sulfide mineral beneficiation, with bacteria and their metabolites, promises to reduce the environmental impact left by the mining industry. In this study, the attachment of Leptospirillum ferrooxidans, L.f, to chalcopyrite and pyrite was investigated through [...] Read more.
The replacement of depressants used in sulfide mineral beneficiation, with bacteria and their metabolites, promises to reduce the environmental impact left by the mining industry. In this study, the attachment of Leptospirillum ferrooxidans, L.f, to chalcopyrite and pyrite was investigated through Scanning Electron Microscopy (SEM). The impact of selective attachment, bacterial growth conditions, and extracellular polymeric substances (EPS) was investigated through bio-flotation. L.f exhibits selective attachment to pyrite between 0 h and 168 h exposure via an indirect contact mechanism. Separation of chalcopyrite from pyrite was achieved through exposing the minerals for 72 h with an L.f culture grown on either HH media, chalcopyrite, or pyrite. The results produced 80.4, 43.4, and 47.4% recovery of chalcopyrite, respectively. However, EPS supernatant extracted from L.f grown on chalcopyrite, conditioned for 48 h, provided the best separation efficiency by the selective depression of pyrite resulting in 95.8% Cu recovery. Polysaccharide-rich EPS selectively attaches to pyrite within 48 h, depressing its floatability and ensuring successful separation with a PIPX collector. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Depressing Iron Mineral by Metallic-Starch Complex (MSC) in Reverse Flotation and Its Mechanism
Minerals 2018, 8(3), 85; https://doi.org/10.3390/min8030085
Received: 31 January 2018 / Revised: 20 February 2018 / Accepted: 22 February 2018 / Published: 27 February 2018
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Abstract
A series of metallic-starch complex (MSC) solutions, synthesized by mixing relevant metallic ionic solutions with the caustic starch solution, were used as the flotation depressants to investigate their depressing effects on hematite ore. The MSC is a nano-sized colloidal complex which is configured [...] Read more.
A series of metallic-starch complex (MSC) solutions, synthesized by mixing relevant metallic ionic solutions with the caustic starch solution, were used as the flotation depressants to investigate their depressing effects on hematite ore. The MSC is a nano-sized colloidal complex which is configured by hydrophilic metallic hydroxide as the colloidal nucleus on which starch and hydroxyl complex are adsorbed, resulting in a larger molecule than starch itself. The flotation tests showed that the depressing abilities of various MSC (Fe3+, Zn2+, Pb2+ and Mg2+) on the iron minerals were higher than the caustic starch, and the order of depression ability was: Zn2+-starch > Pb2+-starch > Fe3+-starch > Mg2+-starch > caustic starch. Based on the adsorption analysis, the high depressing ability of the MSC arose from increasing the adsorption density of starch on iron minerals and slightly reducing the absorption of the collector dodecylamine. Adsorption behaviour also indicated that the adsorption of the MSC on mineral surfaces was thicker than the caustic starch, and among various MSC the adsorption of Fe3+-starch exhibited the thickest adsorption layer while that of Mg2+-starch the thinnest. Zeta potential indicated that with a weaker electronegativity than the caustic starch, MSC adsorbed onto iron minerals more easily, and the strong electrostatic adsorption with the aid of the hydrogen bonding and chemisorption agreed well with the high depressing ability of the MSC. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Classification of Flotation Frothers
Minerals 2018, 8(2), 53; https://doi.org/10.3390/min8020053
Received: 23 November 2017 / Revised: 9 January 2018 / Accepted: 30 January 2018 / Published: 7 February 2018
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Abstract
In this paper, a scheme of flotation frothers classification is presented. The scheme first indicates the physical system in which a frother is present and four of them i.e., pure state, aqueous solution, aqueous solution/gas system and aqueous solution/gas/solid system are distinguished. As [...] Read more.
In this paper, a scheme of flotation frothers classification is presented. The scheme first indicates the physical system in which a frother is present and four of them i.e., pure state, aqueous solution, aqueous solution/gas system and aqueous solution/gas/solid system are distinguished. As a result, there are numerous classifications of flotation frothers. The classifications can be organized into a scheme described in detail in this paper. The frother can be present in one of four physical systems, that is pure state, aqueous solution, aqueous solution/gas and aqueous solution/gas/solid system. It results from the paper that a meaningful classification of frothers relies on choosing the physical system and next feature, trend, parameter or parameters according to which the classification is performed. The proposed classification can play a useful role in characterizing and evaluation of flotation frothers. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Hemimorphite Flotation with 1-hydroxydodecylidene-1,1-diphosphonic acid and Its Mechanism
Minerals 2018, 8(2), 38; https://doi.org/10.3390/min8020038
Received: 8 December 2017 / Revised: 12 January 2018 / Accepted: 15 January 2018 / Published: 24 January 2018
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Abstract
1-hydroxydodecylidene-1,1-diphosphonic acid (HDDPA) was prepared and first applied in flotation of hemimorphite. HDDPA exhibited superior flotation performances for recovery of hemimorphite in comparison with lauric acid, and it also possessed good selectivity against quartz flotation under pH 7.0–11.0. Contact angle results revealed that [...] Read more.
1-hydroxydodecylidene-1,1-diphosphonic acid (HDDPA) was prepared and first applied in flotation of hemimorphite. HDDPA exhibited superior flotation performances for recovery of hemimorphite in comparison with lauric acid, and it also possessed good selectivity against quartz flotation under pH 7.0–11.0. Contact angle results revealed that HDDPA preferred to attach on hemimorphite rather than quartz and promoted the hydrophobicity of hemimorphite surfaces. In the presence of HDDPA anions, the zeta potential of hemimorphite particles shifted to more negative value even if hemimorphite was negatively charged, inferring a strong chemisorption of hemimorphite to HDDPA. The Fourier transform infrared (FTIR) recommended that HDDPA might anchor on hemimorphite surfaces through bonding the oxygen atoms of its P(=O)–O groups with surface Zn(II) atoms. X-ray photoelectron spectroscopy (XPS) gave additional evidence that the Zn(II)-HDDPA surface complexes were formed on hemimorphite. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Influence of the Interaction between Sphalerite and Pyrite on the Copper Activation of Sphalerite
Minerals 2018, 8(1), 16; https://doi.org/10.3390/min8010016
Received: 14 December 2017 / Revised: 8 January 2018 / Accepted: 10 January 2018 / Published: 12 January 2018
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Abstract
In this paper, the effect of pyrite on the activation of sphalerite was investigated by micro-flotation, copper adsorption experiments, X-ray photoelectron spectroscopy (XPS), and electrochemical measurement. The micro-flotation test results showed that the recovery and flotation rate of sphalerite with copper sulphate as [...] Read more.
In this paper, the effect of pyrite on the activation of sphalerite was investigated by micro-flotation, copper adsorption experiments, X-ray photoelectron spectroscopy (XPS), and electrochemical measurement. The micro-flotation test results showed that the recovery and flotation rate of sphalerite with copper sulphate as activator and butyl xanthate as collector were significantly decreased with the increasing content of pyrite in pulp. Cu2+ adsorption results indicated that the adsorption of Cu2+ on the sphalerite surface were decreased when pyrite was present in the pulp. XPS surface analysis demonstrated that the proportion of Cu+ species increased in the activation products on the sphalerite surface, but the total atomic concentration of Cu atom was decreased. Linear voltammetry measurement suggested that the current density of Cu+ species oxidizing to Cu2+ species was increased when sphalerite was electrically contacted with pyrite, which confirmed the increased proportion of Cu+ species on Cu-activation sphalerite surface when contacting with pyrite. These results indicated that there is not only a competitive adsorption for cupric ions (Cu2+), but the galvanic interaction between sphalerite and pyrite also has a significant influence on the copper activation of sphalerite. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Discovery of a Novel Cationic Surfactant: Tributyltetradecyl-Phosphonium Chloride for Iron Ore Flotation: From Prediction to Experimental Verification
Minerals 2017, 7(12), 240; https://doi.org/10.3390/min7120240
Received: 28 October 2017 / Revised: 24 November 2017 / Accepted: 28 November 2017 / Published: 2 December 2017
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Abstract
In this work, tributyltetradecyl-phosphonium chloride (TTPC), has been first introduced to be a novel and efficient cationic surfactant for cationic reverse flotation separation of quartz from magnetite. The first-principles density functional theory calculations, Zeta potential measurements and adsorption isotherm measurements consistently predict that [...] Read more.
In this work, tributyltetradecyl-phosphonium chloride (TTPC), has been first introduced to be a novel and efficient cationic surfactant for cationic reverse flotation separation of quartz from magnetite. The first-principles density functional theory calculations, Zeta potential measurements and adsorption isotherm measurements consistently predict that TTPC may be a promising collector that is better than dodecyl triethyl ammonium chloride (DTAC), based on the facts that TTPC and DTAC both prefer to physically adsorb on the quartz surface owing to electrostatic force, but the active part (P+(C4H9)3) of TTPC takes much more positive charges than that (N+(CH3)3) of DTAC. The micro-flotation and Bench-scale flotation results further verify that TTPC presents a stronger collecting power and much better selectivity for iron ore reverse flotation in comparison to the conventional collector DTAC. Furthermore, the corresponding adsorption mechanism of TTPC on the quartz have also been investigated in detail. This work might show a good example to discover a potential candidate collector by analogy with a known excellent collector based on reasonable prediction. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Study on the Dispersion Mechanism of Citric Acid on Chlorite in Hematite Reverse Flotation System
Minerals 2017, 7(11), 221; https://doi.org/10.3390/min7110221
Received: 29 September 2017 / Revised: 31 October 2017 / Accepted: 9 November 2017 / Published: 13 November 2017
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Abstract
The adhesion behavior between particles in the pulp will seriously affect the index of concentrate. In this paper, the effect of citric acid on chlorite in hematite reverse flotation system was studied. The flotation test and settlement test of artificial mixed ore showed [...] Read more.
The adhesion behavior between particles in the pulp will seriously affect the index of concentrate. In this paper, the effect of citric acid on chlorite in hematite reverse flotation system was studied. The flotation test and settlement test of artificial mixed ore showed that a lower dosage of citric acid could significantly improve the removal rate of chlorite. The mineral contact angle measurement and zeta potential analysis, combined with the extended DLVO theory showed that chlorite is easily adsorbed on the surface of hematite, results in a lower removal rate, and the phenomenon was analyzed by a laser particle size analyzer and optical microscope. The results showed that citric acid can reduce the apparent grain size of artificial mixed ore and improve the dispersion degree of pulp by changing the wettability and surface potential of the minerals, thus increased the removal rate of chlorite. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
The Influence of Backwater Al3+ on Diaspore Bauxite Flotation
Minerals 2017, 7(10), 195; https://doi.org/10.3390/min7100195
Received: 29 August 2017 / Revised: 7 October 2017 / Accepted: 10 October 2017 / Published: 15 October 2017
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Abstract
The effect of Al3+ in backwater on the flotation of diaspore bauxite was investigated by micro-flotation tests and the underlying mechanisms were investigated by inductively coupled plasma (ICP) measurement, zeta potential measurements, solution chemistry analyses, and synchrotron near edge X-ray absorption fine [...] Read more.
The effect of Al3+ in backwater on the flotation of diaspore bauxite was investigated by micro-flotation tests and the underlying mechanisms were investigated by inductively coupled plasma (ICP) measurement, zeta potential measurements, solution chemistry analyses, and synchrotron near edge X-ray absorption fine structure (NEXAFS) analyses. The ICP measurement results show the concentration of Al3+ in backwater was up to 1 × 10−4 mol/L. The micro-flotation results indicated that backwater Al3+ reduced the flotation recovery of diaspore and improved the flotation recovery of kaolinite at pH 9, which was the pH value used in the industrial flotation. The adsorption of Al3+ species changed the zeta potential, the Al atomic abundance, and the number of active sites on the mineral surface. In particular, the result of solution chemistry analyses and synchrotron NEXAFS analyses show that the Al3+ in backwater was adsorbed on the mineral surface in the form of Al(OH)3 (s), and the bond of –Al–O–Al–(OH)2 or –Al/Si–O–Al–(OH)2 was formed at pH 9. It changed the intensity of hydrogen bond force between minerals and collectors, and resulted in the depression of diaspore flotation and the activation of kaolinite flotation. This study can be used to guide the application of backwater in the flotation of diaspore bauxite in industry. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Flotation Behavior of Different Colored Fluorites Using Sodium Oleate as a Collector
Minerals 2017, 7(9), 159; https://doi.org/10.3390/min7090159
Received: 28 July 2017 / Revised: 24 August 2017 / Accepted: 29 August 2017 / Published: 1 September 2017
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Abstract
Using sodium oleate (NaOL) as a collector, the flotation characteristics of natural colorless fluorite (CF), green fluorite (GF), and purple fluorite (PF) were investigated through micro-flotation tests, collector adsorption measurements, and surface tension measurement. The micro-flotation results indicated that CF had a much [...] Read more.
Using sodium oleate (NaOL) as a collector, the flotation characteristics of natural colorless fluorite (CF), green fluorite (GF), and purple fluorite (PF) were investigated through micro-flotation tests, collector adsorption measurements, and surface tension measurement. The micro-flotation results indicated that CF had a much better flotation response than both GF and PF, and had higher floatation recovery. The results demonstrated a considerable discrepancy in the interfacial properties between colorless and colored fluorite, even though all the samples were obtained from the same deposit, holding a similar high purity of CaF2. The adsorption capacity of CF, GF, and PF for NaOL was 2.27, 4.18, and 8.21 × 10−6 mol/g under neutral conditions, respectively. Fourier transform infrared (FT-IR) measurements revealed that the carboxyl groups of NaOL reacted with Ca sites on the surface of fluorites by chemical adsorption. From the zeta potential analyses, PF exhibited a lower positive potential than CF and GF, mainly due to its surface carbonation. In the presence of NaOL, the surface potential of fluorites changed from positive to negative because the NaOL collector had been adsorbed onto the mineral surface and changed their surface potential, which was consistent with the flotation results at different pH values. We found that the floatability of the fluorite samples was influenced by their surface roughness, measured by an atomic force microscope (AFM) and scanning electron microscope (SEM). PF can be floated with adding more reagent dosage than CF and GF to compensate for its higher surface roughness. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
The Role of Water Glass in the Flotation Separation of Fine Fluorite from Fine Quartz
Minerals 2017, 7(9), 157; https://doi.org/10.3390/min7090157
Received: 8 August 2017 / Revised: 22 August 2017 / Accepted: 23 August 2017 / Published: 28 August 2017
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Abstract
Fluorite is the principal mineral of fluorine and usually coexists with quartz in deposits. The removal of fine quartz in fluorite concentrate is the main problem in fluorite flotation. In this study, the flotation tests on fluorite, quartz and a weight equivalent mixture [...] Read more.
Fluorite is the principal mineral of fluorine and usually coexists with quartz in deposits. The removal of fine quartz in fluorite concentrate is the main problem in fluorite flotation. In this study, the flotation tests on fluorite, quartz and a weight equivalent mixture (all less than 10 μm) using water glass (with different modulus) as depressants and sodium oleate as collector were conducted. The mechanism of fine quartz entering the fluorite concentrate was investigated through optional observations and rheology measurements on the flotation pulp. The particle interactions between fine fluorite and quartz under flotation-related conditions were analyzed through zeta potential measurements and DLVO calculations. The results revealed that there existed strong hetero-coagulation between fluorite and quartz particles in the flotation pulp, which could be the main reason for the quartz entering the fluorite concentrate in the flotation process. Water glass with higher modulus could eliminate the hetero-coagulation more totally but inevitably influences the flotability of fluorite. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
Flotation Behaviors of Perovskite, Titanaugite, and Magnesium Aluminate Spinel Using Octyl Hydroxamic Acid as the Collector
Minerals 2017, 7(8), 134; https://doi.org/10.3390/min7080134
Received: 18 June 2017 / Revised: 15 July 2017 / Accepted: 28 July 2017 / Published: 2 August 2017
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Abstract
The flotation behaviors of perovskite, titanaugite, and magnesium aluminate spinel (MA-spinel), using octyl hydroxamic acid (OHA) as the collector, were investigated using microflotation experiments, zeta-potential measurements, Fourier transform infrared (FT-IR) analyses, X-ray photoelectron spectroscopy (XPS) analyses, and flotation experiments on artificially mixed minerals. [...] Read more.
The flotation behaviors of perovskite, titanaugite, and magnesium aluminate spinel (MA-spinel), using octyl hydroxamic acid (OHA) as the collector, were investigated using microflotation experiments, zeta-potential measurements, Fourier transform infrared (FT-IR) analyses, X-ray photoelectron spectroscopy (XPS) analyses, and flotation experiments on artificially mixed minerals. The microflotation experiments show that the floatability of perovskite is clearly better than titanaugite and MA-spinel at around pH 5.5, while titanaugite possesses certain floatability at pH 6.0–6.5, and MA-spinel displays good floatability at pH > 8.0. The results of the FT-IR and XPS analyses show that OHA mainly interacts with Ti, resulting in perovskite flotation, and that the Al on titanaugite, as well as the Mg and Al on the MA-spinel surface, chemically react with OHA under acidic conditions. However, OHA mainly reacts with the Ti and Ca on the perovskite surface, Ca and Mg on the titanaugite surface, and Mg and Al on the MA-spinel surface under alkaline conditions. The results of the artificially mixed mineral flotation experiment show that the concentrate of TiO2 grade increased from 19.73% to 30.18% at pH 5.4, which indicates that a weakly acidic solution is the appropriate condition for the flotation separation of perovskite from titanaugite and MA-spinel. The results of the modified slag flotation experiments show that the TiO2 grade of concentrate increased from 18.13% to 23.88% at pH 5.4, through the open circuit test of “one roughing and one cleaning”. OHA displays selectivity toward perovskite in the modified slag flotation, but the consumption of H2SO4 is very high. The CaSO4 precipitate covered on the mineral surfaces results in poor TiO2 grade and recovery. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
The Effect of Conditioning on the Flotation of Pyrrhotite in the Presence of Chlorite
Minerals 2017, 7(7), 125; https://doi.org/10.3390/min7070125
Received: 29 May 2017 / Revised: 14 July 2017 / Accepted: 15 July 2017 / Published: 20 July 2017
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Abstract
The influence of conditioning on the flotation of pyrrhotite in the presence of chlorite was investigated through flotation tests, sedimentation tests, and X-ray photoelectron spectroscopy (XPS) analysis. The flotation results show that chlorite slimes dramatically impair the flotation of pyrrhotite. Sedimentation and flotation [...] Read more.
The influence of conditioning on the flotation of pyrrhotite in the presence of chlorite was investigated through flotation tests, sedimentation tests, and X-ray photoelectron spectroscopy (XPS) analysis. The flotation results show that chlorite slimes dramatically impair the flotation of pyrrhotite. Sedimentation and flotation tests reveal that conditioning can effectively remove chlorite slimes from pyrrhotite surfaces, resulting in an enhanced flotation recovery of pyrrhotite. When mixed minerals were conditioned under the natural atmosphere, a faster conditioning speed and longer conditioning time decreased the flotation recovery of pyrrhotite. However, when mixed minerals were conditioned under a nitrogen atmosphere, a more intensive conditioning process provided better flotation results. XPS analyses illustrate that a faster conditioning speed and longer conditioning time under the natural atmosphere accelerates the oxidation of pyrrhotite, leading to a decrease in the flotation recovery of pyrrhotite. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
The Activation Mechanism of Bi3+ Ions to Rutile Flotation in a Strong Acidic Environment
Minerals 2017, 7(7), 113; https://doi.org/10.3390/min7070113
Received: 8 June 2017 / Revised: 27 June 2017 / Accepted: 28 June 2017 / Published: 2 July 2017
Cited by 8 | PDF Full-text (5646 KB) | HTML Full-text | XML Full-text
Abstract
Lead hydroxyl compounds are known as rutile flotation of the traditional activated component, but the optimum pH range for flotation is 2–3 using styryl phosphoric acid (SPA) as collector, without lead hydroxyl compounds in slurry solution. In this study, Bi3+ ions as [...] Read more.
Lead hydroxyl compounds are known as rutile flotation of the traditional activated component, but the optimum pH range for flotation is 2–3 using styryl phosphoric acid (SPA) as collector, without lead hydroxyl compounds in slurry solution. In this study, Bi3+ ions as a novel activator was investigated. The results revealed that the presence of Bi3+ ions increased the surface potential, due to the specific adsorption of hydroxyl compounds, which greatly increases the adsorption capacity of SPA on the rutile surface. Bi3+ ions increased the activation sites through the form of hydroxyl species adsorbing on the rutile surface and occupying the steric position of the original Ca2+ ions. The proton substitution reaction occurred between the hydroxyl species of Bi3+ ions (Bi(OH)n+(3−n)) and the hydroxylated rutile surface, producing the compounds of Ti-O-Bi2+. The micro-flotation tests results suggested that Bi3+ ions could improve the flotation recovery of rutile from 61% to 90%, and from 61% to 64% for Pb2+ ions. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessArticle
The Influence of Common Monovalent and Divalent Chlorides on Chalcopyrite Flotation
Minerals 2017, 7(7), 111; https://doi.org/10.3390/min7070111
Received: 2 June 2017 / Revised: 25 June 2017 / Accepted: 26 June 2017 / Published: 1 July 2017
Cited by 4 | PDF Full-text (4940 KB) | HTML Full-text | XML Full-text
Abstract
Much attention has been paid to the flotation of chalcopyrite using saline seawater. However, the influence of salt ions on mineral flotation is complex, and different salts may play various roles—either beneficial or detrimental. This study investigated the effects of common chlorides (Cl [...] Read more.
Much attention has been paid to the flotation of chalcopyrite using saline seawater. However, the influence of salt ions on mineral flotation is complex, and different salts may play various roles—either beneficial or detrimental. This study investigated the effects of common chlorides (Cl) of Na+, K+, Mg2+, and Ca2+ in seawater on chalcopyrite floatability. The presence of Na+, K+, and Ca2+ resulted in greater chalcopyrite recovery, with this effect being more pronounced for the monovalent cations. In contrast, the addition of Mg2+ resulted in decreased chalcopyrite flotation efficiency. Contact angle measurements showed that the presence of monovalent cations increased the hydrophobicity of the chalcopyrite surface, while the presence of divalent cations reduced its hydrophobicity, depending on the concentration. Zeta potential, pulp species, and X-ray photoelectron spectroscopy (XPS) cross-confirmed the precipitation of Mg(OH)2 on the chalcopyrite surface when Mg concentration was 10−2 M and pulp pH was 10. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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Open AccessCase Report
Multi-Stage Flotation for the Removal of Ash from Fine Graphite Using Mechanical and Centrifugal Forces
Minerals 2018, 8(1), 15; https://doi.org/10.3390/min8010015
Received: 5 December 2017 / Revised: 7 January 2018 / Accepted: 10 January 2018 / Published: 11 January 2018
Cited by 5 | PDF Full-text (3823 KB) | HTML Full-text | XML Full-text
Abstract
Graphite ore collected from Hunan province, south China was characterized by chemical analysis, X-ray diffraction, and optical microscopy. Rougher and multi-stage flotation tests using a mechanical flotation cell and a flotation column containing an additional centrifugal force field were carried out to promote [...] Read more.
Graphite ore collected from Hunan province, south China was characterized by chemical analysis, X-ray diffraction, and optical microscopy. Rougher and multi-stage flotation tests using a mechanical flotation cell and a flotation column containing an additional centrifugal force field were carried out to promote its grade and economic value. In rougher flotation, both the mechanical flotation cell and flotation column reduced the ash content of the graphite ore from 15.43% to 10.8%, while the yield of the flotation column (91.41%) was much higher than that of the mechanical flotation cell (50%). In the presence of hydrophobic graphite, the seriously entrained gangue restricted further improvement in the quality and economic value of the graphite ore. Therefore, multi-stage flotation circuits were employed to diminish this entrainment. Multi-stage flotation circuits using the two flotation devices further decreased the ash content of the graphite ore to ~8%, while the yield when using the flotation column was much higher than that obtained from the mechanical flotation cell employed. On the other hand, the ash removal efficiency of the flotation column was 3.82-fold higher than that observed for the mechanical flotation cell. The Cleaner 3 flotation circuit using the flotation column decreased the ash content in graphite from 15.43% to 7.97% with a yield of 77.53%. Full article
(This article belongs to the Special Issue Flotation Chemistry)
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