Special Issue "Flotation Reagents"

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Processing and Metallurgy".

Deadline for manuscript submissions: 30 June 2019

Special Issue Editor

Guest Editor
Assoc. Prof. Dr. Saeed Chehreh Chelgani

Minerals and Metallurgical Engineering, Dept. of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-971 87 Luleå, Sweden
Website | E-Mail
Interests: mineral processing; flotation; surface chemistry; rare earth processing; coal preparation; graphite processing; leaching; modeling; neural network; random forest

Special Issue Information

“Without reagents there would be no flotation, and without flotation the mining industry, as we know it today, would not exist.” Handbook of Flotation Reagents by Srdjan M. Bulatovic

Dear Colleagues,

Separation by froth flotation involves many types of reagents. Reagents are mainly used for treating the surface of ores and/or for improving conditions of operations for increasing flotation separation efficiency. Reagents can impact the pulp chemistry and make flotation a complex system involving the interaction of all additives (including collectors, depressants, activators, pH regulators, and frothers). The flotation reagents may remain on the products (slurry, tail, and concentrate) and lead to many environmental problems or have a great impact on downstream processes such as bioleaching. Therefore, fundamental knowledge of chemical reagents, the development of their new types, using them for different conditions, and minerals and surface chemistry studies in the presence of various reagents are typical and essential investigations in mineral processing.

Assoc. Prof. Dr. Saeed Chehreh Chelgani
Guest Editor

Manuscript Submission Information

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Keywords

  • collector
  • frother
  • depressant
  • regulator
  • modifier
  • activator
  • surfactant
  • surface chemistry
  • bioleaching
  • environmental problems

Published Papers (7 papers)

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Research

Open AccessArticle
Effect of Depressants and Temperature on Bastnaesite and Monazite Flotation Separation from a Canadian Rare Earth Element (REE) Ore
Minerals 2019, 9(4), 225; https://doi.org/10.3390/min9040225
Received: 13 March 2019 / Revised: 5 April 2019 / Accepted: 8 April 2019 / Published: 10 April 2019
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Abstract
A full factorial experimental design was conducted to investigate the effect of temperature and depressants on the flotation of monazite and bastnaesite from carbonate gangue minerals. Temperature, sodium silicate, and guar gum dosage were examined. Mineral reconstruction from energy-dispersive x-ray fluorescence (EDXRF) data [...] Read more.
A full factorial experimental design was conducted to investigate the effect of temperature and depressants on the flotation of monazite and bastnaesite from carbonate gangue minerals. Temperature, sodium silicate, and guar gum dosage were examined. Mineral reconstruction from energy-dispersive x-ray fluorescence (EDXRF) data was performed to quantify bastnaesite, monazite, and gangue mineral recoveries. Bastnaesite and monazite both follow first-order rates of recovery, with bastnaesite recovering faster and to a larger extent than monazite. The main gangue minerals were depressed together. Optimal separation efficiency was achieved using a larger Na2SiO3 dosage (2400 g/t), no guar gum addition, and a high temperature (75 °C). The rate of bastnaesite recovery increased with the temperature, while sodium silicate improved the ultimate recovery. An economic analysis was performed to evaluate the impact of increasing Rare Earth Element (REE) recovery by allowing a lower grade concentrate to be generated. Despite the high value of REEs, increasing recovery by producing a concentrate bearing more than 68 wt % carbonaceous gangue was uneconomical. Full article
(This article belongs to the Special Issue Flotation Reagents)
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Open AccessArticle
Selective Separation of Hematite by a Synthesized Depressant in Various Scales of Anionic Reverse Flotation
Minerals 2019, 9(2), 124; https://doi.org/10.3390/min9020124
Received: 24 January 2019 / Revised: 16 February 2019 / Accepted: 18 February 2019 / Published: 20 February 2019
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Abstract
Demand for high-quality iron concentrate is significantly increasing around the world. Thus, the development of the techniques for a selective separation and rejection of typical associated minerals in the iron oxide ores, such as phosphorous minerals (mainly apatite group), is a high priority. [...] Read more.
Demand for high-quality iron concentrate is significantly increasing around the world. Thus, the development of the techniques for a selective separation and rejection of typical associated minerals in the iron oxide ores, such as phosphorous minerals (mainly apatite group), is a high priority. Reverse anionic flotation by using sodium silicate (SS) as an iron oxide depressant is one of the techniques for iron ore processing. This investigation is going to present a synthesized reagent “sodium co-silicate (SCS)” for hematite depression through a reverse anionic flotation. The main hypothesis is the selective depression of hematite and, simultaneously, modification of the pulp pH by SCS. Various flotation experiments, including micro-flotation, and batch flotation of laboratory and industrial scales, were conducted in order to compare the depression selectivity of SS versus SCS. Outcomes of flotation tests at the different flotation scales demonstrated that hematite depression by SCS is around 3.3% higher than by SS. Based on flotation experiment outcomes, it was concluded that SCS can modify the pH of the process at ~9.5, and the plant reagents (including NaOH, Na2CO3, and SS gel) can be replaced by just SCS, which can also lead to a higher efficiency in the plant. Full article
(This article belongs to the Special Issue Flotation Reagents)
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Open AccessArticle
Selective Separation of Scheelite from Calcite by Self-Assembly of H2SiO3 Polymer Using Al3+ in Pb-BHA Flotation
Minerals 2019, 9(1), 43; https://doi.org/10.3390/min9010043
Received: 10 December 2018 / Revised: 8 January 2019 / Accepted: 10 January 2019 / Published: 13 January 2019
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Abstract
The flotation separation of scheelite from calcite is problematic, where sodium silicate modified by polyvalent metal ions has shown some advantages for selective depression. In this study, an Al-Na2SiO3 polymer was used as the depressant for the flotation separation of [...] Read more.
The flotation separation of scheelite from calcite is problematic, where sodium silicate modified by polyvalent metal ions has shown some advantages for selective depression. In this study, an Al-Na2SiO3 polymer was used as the depressant for the flotation separation of scheelite from calcite using a lead complex of benzohydroxamic acid (Pb-BHA) as the collector. Furthermore, a number of measurements were conducted to investigate the structure of the Al-Na2SiO3 polymer and its adsorption behavior with Pb-BHA complexes on the mineral surface. Flotation experiments indicated that the Al-Na2SiO3 polymer shows good selectivity for the flotation separation of scheelite from calcite at pH 8, where the optimum ratio of sodium silicate to aluminum sulfate was 2:1. Fourier-Transform Infrared (FTIR) and solution chemical analyses revealed that aluminum hydroxide complexes and the hydroxy moiety of silicic acid are able to self-assemble via condensation affording an Al-Na2SiO3 polymer, i.e., a composite aluminosilicate polymer. The zeta potential measurements and adsorption capacity measurements indicated that, upon adsorption of the Al-Na2SiO3 polymer and Pb-BHA complexes on the mineral surface, the Al-Na2SiO3 polymer had less influence on the adsorption of Pb-BHA complexes on the scheelite surface, while the opposite was true for calcite. Therefore, more Pb-BHA complexes and fewer Al-Na2SiO3 polymers were deposited on the scheelite surface, while fewer Pb-BHA complexes and more Al-Na2SiO3 polymers were adsorbed on the calcite surface. The selective separation of scheelite from calcite was attributed to the cooperative selectivity of the Pb-BHA complexes and Al-Na2SiO3 polymer. Full article
(This article belongs to the Special Issue Flotation Reagents)
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Open AccessArticle
Adsorption Behavior of Methyl Laurate and Dodecane on the Sub-Bituminous Coal Surface: Molecular Dynamics Simulation and Experimental Study
Minerals 2019, 9(1), 30; https://doi.org/10.3390/min9010030
Received: 12 December 2018 / Revised: 2 January 2019 / Accepted: 8 January 2019 / Published: 9 January 2019
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Abstract
Biodiesel was found to be a more effective collector on low-rank coal flotation than the common oily collectors (diesel and kerosene) in previous research. However, the micro-adsorption behavior of these collectors on the coal surface remains to be further explored. In the present [...] Read more.
Biodiesel was found to be a more effective collector on low-rank coal flotation than the common oily collectors (diesel and kerosene) in previous research. However, the micro-adsorption behavior of these collectors on the coal surface remains to be further explored. In the present work, the adsorption behavior of methyl laurate and dodecane, representing biodiesel and common oily collectors, was investigated using experimental and molecular dynamics (MD) simulation methods. The results of MD simulations showed that dodecane was difficult to diffuse on the surface of sub-bituminous coal and formed a spherical structure on the surface of sub-bituminous coal. Methyl laurate was adsorbed on the surface of coal via the head group (ester group), while the tail group (alkyl chain) was exposed to a liquid environment, forming a wider network structure on the coal surface. The above results, mainly attributed to methyl laurate, had a higher interaction with the sub-bituminous surface compared to dodecane. The self-diffusion coefficient results showed that the aggregate configurations of methyl laurate cause higher water mobility, which was more conducive to enhancing the hydrophobicity of the coal surface. The adhesion efficiency measurement and X-ray photoelectron spectrometer (XPS) analysis confirmed that methyl laurate could cover more oxygen-containing functional groups on the coal surface than dodecane, thus enhancing the hydrophobicity of coal. The results of simulations conformed to the experimental results. Full article
(This article belongs to the Special Issue Flotation Reagents)
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Open AccessArticle
A Mechanism for the Adsorption of 2-(Hexadecanoylamino)Acetic Acid by Smithsonite: Surface Spectroscopy and Microflotation Experiments
Minerals 2019, 9(1), 15; https://doi.org/10.3390/min9010015
Received: 30 October 2018 / Revised: 6 December 2018 / Accepted: 20 December 2018 / Published: 26 December 2018
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Abstract
Zinc is mostly extracted from oxidized zinc and zinc sulfide minerals, and this process involves flotation as a key step. While it is easier to float the sulfide mineral, its consumption and depletion has led to an increased reliance on oxidized zinc minerals, [...] Read more.
Zinc is mostly extracted from oxidized zinc and zinc sulfide minerals, and this process involves flotation as a key step. While it is easier to float the sulfide mineral, its consumption and depletion has led to an increased reliance on oxidized zinc minerals, including smithsonite. Hence, the development of efficient ways of collecting smithsonite by flotation is an important objective. Herein, we describe the use of 2-(hexadecanoylamino)acetic acid (HAA), a novel surfactant, as a collector during smithsonite flotation. The mechanism and flotation performance of HAA during smithsonite flotation was investigated by total organic carbon (TOC) content studies, zeta potential measurements, Fourier-transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses, combined with microflotation experiments. The flotation results revealed that HAA was an excellent collector in pulp over a wide pH range (9–12) and at a relatively low concentration (2 × 10−4 mol/L), at which a recovery of close to 90% of the smithsonite mineral was obtained. TOC content studies revealed that the good flotation recovery was ascribable to large amounts of collector molecule adsorbed on the smithsonite surface, while zeta potential measurements showed that the HAA was chemically adsorbed onto the smithsonite. FTIR and XPS analyses revealed that the HAA collector molecules adsorbed onto the smithsonite surface as zinc–HAA complexes involving carboxylate moieties and Zn sites on the smithsonite surface in alkaline solution. Full article
(This article belongs to the Special Issue Flotation Reagents)
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Open AccessArticle
An Alternative Depressant of Chalcopyrite in Cu–Mo Differential Flotation and Its Interaction Mechanism
Minerals 2019, 9(1), 1; https://doi.org/10.3390/min9010001
Received: 15 November 2018 / Revised: 7 December 2018 / Accepted: 11 December 2018 / Published: 20 December 2018
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Abstract
Carboxymethylcellulose (CMC) is a nontoxic and biodegradable polysaccharide, which can potentially replace the frequently used hazardous depressants in Cu–Mo separation. However, a lack of understanding of the interaction mechanism between the CMC and the minerals has hindered its application. In the present study, [...] Read more.
Carboxymethylcellulose (CMC) is a nontoxic and biodegradable polysaccharide, which can potentially replace the frequently used hazardous depressants in Cu–Mo separation. However, a lack of understanding of the interaction mechanism between the CMC and the minerals has hindered its application. In the present study, it is found that 50 mg·L−1 CMC can inhibit chalcopyrite entirely in the pH range 4–6, while having little effect on molybdenite. The results also showed that the inhibition effect of the depressant for chalcopyrite enhanced with the increase of the degree of substitution (DS) and molecular weight (Mw) of CMC. The low DS and high Mw of CMC were detrimental to the Cu–Mo separation flotation. Furthermore, CMC adsorption was found to be favored by a positive zeta potential but hindered by the protonation of the carboxyl groups. An electrochemical study showed that CMC inhibited 92.9% of the electrochemical reaction sites of chalcopyrite and greatly reduced the production of hydrophobic substances. The XPS and FTIR measurements displayed that the chemisorption was mainly caused by Fe3+ on the chalcopyrite surface and the carboxyl groups in the CMC molecular structure. Full article
(This article belongs to the Special Issue Flotation Reagents)
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Open AccessArticle
A Novel Method to Limit the Adverse Effect of Fine Serpentine on the Flotation of Pyrite
Minerals 2018, 8(12), 582; https://doi.org/10.3390/min8120582
Received: 7 November 2018 / Revised: 30 November 2018 / Accepted: 6 December 2018 / Published: 10 December 2018
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Abstract
A novel method to limit the adverse effect of fine serpentine on the flotation of pyrite was investigated in this paper. The flotation results showed that coarser serpentine possessed a weaker depression effect on the pyrite flotation process, and the use of KAl(SO [...] Read more.
A novel method to limit the adverse effect of fine serpentine on the flotation of pyrite was investigated in this paper. The flotation results showed that coarser serpentine possessed a weaker depression effect on the pyrite flotation process, and the use of KAl(SO4)2·12H2O could efficiently limit the detrimental effect of fine serpentine on pyrite with a maximum increase of pyrite recovery from 14% to 86% at pH 9.0. The results of particle size measurements and rheological measurements exhibited that the addition of KAl(SO4)2·12H2O increased the particle size of serpentine buta hrdly affected the particle size of pyrite, then limited the formation of serpentine-pyrite aggregates. Adsorption test results showed that the adsorption density of potassium butyl xanthate (PBX) onto pyrite regained with the addition of KAl(SO4)2·12H2O, thereby achieving good flotation improvement. It can be concluded that KAl(SO4)2·12H2O is likely to be an effective pyrite flotation reagent, especially in the presence of fine serpentine. Full article
(This article belongs to the Special Issue Flotation Reagents)
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