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Flotation Chemistry, Volume II

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

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 38722

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Special Issue Editors

Prof. Dr. Zhiyong Gao

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Guest Editor

School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
Interests: flotation of oxide minerals; mineral crystal chemistry; flotation reagent molecular design; mineral/reagent/water interfacial science; waste treatment in minerals processing
Special Issues, Collections and Topics in MDPI journals

Dr. Wenjihao Hu

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Co-Guest Editor

Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2R3, Canada
Interests: interfacial science and engineering for selective separation; membrane technology; oil/water separation; desalination; wastewater treatment; mineral surface science; conductive AFM; synthesis of 2D materials; AFM force measurement; material characterization

Dr. Peipei Wang

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Co-Guest Editor

ARC Centre of Excellence for Enabling Eco-Efficient Beneficiation of Minerals, Newcastle Institute for Energy and Resources, University of Newcastle, Shortland, NSW 2307, Australia
Interests: mineral processing; particle/bubble motion and dynamics in fluid; chemical adsorption; foams; solution chemistry; colloids and interface

Dr. Kirsten Claire Corin

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Co-Guest Editor

Centre for Minerals Research, University of Cape Town, Cape Town 7700, South Africa
Interests: water within flotation; flotation chemistry; flotation reagents; electrochemistry of flotation; grinding chemistry
Special Issues, Collections and Topics in MDPI journals

Dr. Ljudmilla Bokányi

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Co-Guest Editor

Department of Bioprocessing and Reaction Techniques, Institute of Raw Materials Preparation and Environmental Processing University of Miskolc, 3515 Miskolc, Hungary
Interests: interfacial phenomena; flotation chemistry; modelling and technology

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

This Special Issue is dedicated to Prof. Yuehua Hu, who is currently Professor at the school of minerals processing and bioengineering, Central South University, on the occasion of his 60th birthday (to be celebrated on 1 January, 2022), and in honor of his many achievements in flotation chemistry.

Brief Introduction about Prof. Hu

Professor Yuehua Hu is now the executive vice-president of Central South University (CSU), and the academic leader of mineral engineering discipline of CSU. He also serves as the vice president of Nonferrous Metals Society of China, and vice president of China Mineral Processing Congress. Since 1991, he has been awarded over RMB120M in competitive grant funding from the National natural science foundation of China, Ministry of Science and Technology, Ministry of Education, and national and private industry. He has received numerous awards and honours over the years. These include the National Science Fund for Distinguished Young Scholars in 1999, Chang Jiang Scholars Program in 2000, National University Distinguished Teacher Award in 2009. As a supervisor or cosupervisor, he has trained 40 PhDs, 42 masters and 11 postdoctoral fellows, 18 of whom are full professors in universities/institutes and half of whom are senior managers in mining companies. He authored and co-authored over 300 papers with 8 highly cited papers, h-index reaching 46. He had more than 70 authorized Chinese patents and most of them has been transfered and/or applied in industry.

Dr. Zhiyong Gao
Dr. Wenjihao Hu
Dr. Peipei Wang
Dr. Kirsten Claire Corin
Dr. Ljudmilla Bokányi
Guest Editors

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Flotation Chemistry in Minerals (20 articles)

Published Papers (14 papers)

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Research

15 pages, 3435 KiB

Open AccessArticle

Influence Mechanism of Magnetized Modified Kerosene on Flotation Behavior of Molybdenite

by Hui Li, Wei Xiao, Jianping Jin and Yuexin Han

Minerals 2022, 12(1), 2; https://doi.org/10.3390/min12010002 - 21 Dec 2021

Cited by 2 | Viewed by 2511

Abstract

The effects and mechanism of magnetized kerosene on the flotation behaviors of molybdenite were studied by micro-flotation, ultraviolet spectrum, infrared spectrum, surface tension, and liquid viscosity. According to the results of micro-flotation, magnetized kerosene improved the flotation recovery of molybdenite, and the improvements were more obvious with smaller molybdenite particles. Spectral analysis showed that the magnetization did not change the chemical composition of kerosene, but transformed the linear aliphatic hydrocarbons in kerosene into linear isomers and reduced the lengths of the carbon chains. Moreover, the magnetization reduced the viscosity of kerosene and oil/water interfacial tension, and improved the dispersion of kerosene in the pulp. The external magnetic field transformed the disorder of the additional magnetic moment in the kerosene molecules into order, and reduced the compactness of the kerosene molecules. The experimental results provided a theoretical explanation for the role of magnetization in mineral flotation. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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12 pages, 3284 KiB

Open AccessFeature PaperArticle

Enhanced Flotation Recovery of Fine Molybdenite Particles Using a Coal Tar-Based Collector

by Yande Chao, Shulei Li, Lihui Gao, Lijuan Sun, Lingni Li, Na Chai and Yijun Cao

Minerals 2021, 11(12), 1439; https://doi.org/10.3390/min11121439 - 20 Dec 2021

Cited by 1 | Viewed by 2648

Abstract

Low flotation efficiency has always been a problem in the separation of low-grade molybdenum ores because of the finely disseminated nature and crystal anisotropy of molybdenite. In this study, a novel kerosene–coal tar collector (KCTC) was prepared and used to explore the feasibility of improving the recovery of fine molybdenite particles. The results showed that KCTC achieved better attaching performance than that shown by kerosene, and the surface coverage and attaching rate constant were improved significantly, especially for finer particles of −38 + 20 μm. Compared with kerosene, KCTC showed more affinity for molybdenite particles and greater adsorbed amounts of KCTC on molybdenite particles were achieved. Moreover, the composite collector was shown to float single molybdenite particles of different sizes, and it was found that the recovery of molybdenite particles of different sizes, particularly in the case of those at −20 μm, was improved dramatically by KCTC. The flotation results of actual molybdenum ores further confirmed that KCTC was beneficial to flotation recovery and the selectivity of molybdenite. This indicated that KCTC is a potential collector for the effective flotation of low-grade deposits of molybdenum ores, and more studies should be conducted on further use in industrial practice. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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10 pages, 1872 KiB

Open AccessArticle

Selection of an Appropriate Depressant in Flotation Separation of Molybdenum Oxide from Fluorapatite

by Jiandong Liu, Binbin Peng, Liping Zhao, Fengwei Bai and Zhiwu Lei

Minerals 2021, 11(10), 1110; https://doi.org/10.3390/min11101110 - 10 Oct 2021

Cited by 2 | Viewed by 2128

Abstract

The depressive efficiency of sodium silicate, sodium hexametaphosphate, and tartaric acid on the flotation separation of molybdenum oxide from fluorapatite were examined using cetylpyridinium chloride (CPC) as the collector. The corresponding depression mechanisms of all three depressants were studied with the use of laboratory measurements. Individual mineral flotation tests and adsorption studies showed that all these depressants have a higher depression effect on fluorapatite than molybdenum oxide. Sodium hexametaphosphate has the strongest depression effect on fluorapatite and can reduce the flotation recovery as low as less than 20%. Infrared spectroscopy and zeta potential tests proved the rationality of the flotation results, indicating that when CPC was used as a collector, the effect of sodium hexametaphosphate on the surface of molybdenum oxide was smaller than that on fluorapatite. The adsorption of hexametaphosphate on the surface of fluorapatite was determined to be physical adsorption. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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13 pages, 4201 KiB

Open AccessArticle

Selective Separation of Chalcopyrite from Galena Using a Green Reagent Scheme

by Kaile Zhao, Chao Ma, Guohua Gu and Zhiyong Gao

Minerals 2021, 11(8), 796; https://doi.org/10.3390/min11080796 - 22 Jul 2021

Cited by 3 | Viewed by 3073

Abstract

The study of the depression effect of non-toxic depressants on the flotation separation of chalcopyrite from galena is of great importance for both industrial applications and theoretical research. The mixed depressant (D_Final) of four common inhibitors—sodium carboxymethyl cellulose, sodium silicate, sodium sulfite, and zinc sulfate—exhibited high selectivity during the separation of chalcopyrite from galena. Flotation tests on an industrial copper–lead bulk concentrate showed that using this depressant mixture can achieve highly efficient separation of chalcopyrite from galena at the natural pH of the pulp. Copper and lead concentrates were produced at grades of 21.88% (Cu) and 75.53% (Pb), with recoveries of 89.07% (Cu) and 98.26% (Pb). This showed a similar performance of D_Final with dichromate, which is a depressant that is widely used in industry, but without the environmental risks or the need for pH control. Zeta potential and Fourier transform infrared (FT-IR) results showed that interaction between the surface of the chalcopyrite and the mixed depressant was prevented by pre-treatment with a composite thiophosphate collector (CSU11), while the mixed depressant could expel/replace the composite thiophosphate on the surface of galena by chemical adsorption, depressing its flotation. This is the reason why this non-toxic depressant achieved the selective depression of galena from chalcopyrite, leading to efficient flotation separation. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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10 pages, 2230 KiB

Open AccessArticle

Elimination of Ferric Ion Effect on Separation between Kyanite and Quartz Using Citric Acid as Regulator

by Yanping Niu, Ya Li, Haoran Sun, Chuanyao Sun, Wanzhong Yin and Hongfeng Xu

Minerals 2021, 11(6), 599; https://doi.org/10.3390/min11060599 - 3 Jun 2021

Viewed by 2575

Abstract

Ferric ions produced during grinding influence the flotation separation between kyanite and quartz adversely. In this study, citric acid was used as a regulator to eliminate the effect of ferric ions on the separation of kyanite from quartz with sodium oleate (NaOL) as a collector. The microflotation test results indicated that the quartz was selectively activated by FeCl₃ and maintained significant quartz recovery. However, the citric acid could selectively eliminate the effect of ferric ions on the quartz and minimally influenced the kyanite. Contact angle tests demonstrated that FeCl₃ significantly increased the interaction between NaOL and quartz, resulting in the high hydrophobicity of quartz, and the addition of citric acid made the quartz surface hydrophilic again but slightly influenced the kyanite. Fourier-transform infrared spectroscopy showed that FeCl₃ facilitated NaOL adsorption onto the quartz surface, and the addition of citric acid eliminated the activation of FeCl₃ on the quartz, resulting in the nonadsorption of NaOL onto the quartz surface. However, the FeCl₃ and citric acid exhibited a negligible effect on NaOL adsorption onto the kyanite surface. X-ray photoelectron spectroscopy analysis indicated that the citric acid eliminated FeCl₃ activation on the quartz. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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15 pages, 6447 KiB

Open AccessArticle

Clean and Feasible Utilization of High Silica Fluorspar Powder via Reverse Flotation: A Pilot Study

by Chenhu Zhang, Jiande Gao, Yuehua Hu, Wei Sun, Fei Lv and Zhenjun Liu

Minerals 2021, 11(6), 555; https://doi.org/10.3390/min11060555 - 24 May 2021

Cited by 1 | Viewed by 2971

Abstract

Fluorite is a nonrenewable mineral used to produce anhydrous hydrofluoric acid (AHF) and aluminum fluoride. The demand for low-grade fluorite powder (CaF₂ < 97%) has fallen sharply owing to the current market conditions. Therefore, a large number of fluorite concentrates have been improved by acid leaching. While this approach can efficiently remove CaCO₃ from fluorite concentrate, the SiO₂ content, which significantly affects AHF consumption during the production of HF or aluminum fluoride, cannot be completely removed. To solve this problem, in this study, we used reverse flotation before leaching the fluorite concentrates. Subsequently, the feasibility of reverse flotation desilication was determined. The obtained results of the ZP (zeta potential) measurements, solution chemistry analysis, FTIR (Fourier transform infrared spectroscopy) analysis, and micro-flotation tests indicated that employing dodecylamine as the collector and citric acid as the depressor could effectively separate sericite from fluorite. The batch flotation experiment and the pilot test were conducted in Chenzhou (Hunan, China) followed by their operation in Xinyuan Mining Co. Ltd., which produces monolithic fluorite ore on the large scale in Asia. Notably, we found that the contents of both SiO₂ and Al₂O₃ were from 2.82%, 1.17% reduced to 1.28%, 0.74% in the batch flotation experiment. The results of the pilot test showed that the new reverse flotation + leaching technology could dramatically reduce the potential environmental impact and costs, thereby significantly improving the economic benefits by satisfying the requirements of the market. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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7 pages, 2430 KiB

Open AccessArticle

Adsorption Behaviors of Straight-Chain Alkanes on a Molybdenite [001]/[100] Surface: A Molecular Dynamics Study

by He Wan, Peng Yi, Juanping Qu, Xianzhong Bu, Wei Yang and Hui Li

Minerals 2021, 11(5), 489; https://doi.org/10.3390/min11050489 - 4 May 2021

Cited by 4 | Viewed by 1788

Abstract

Straight-chain alkanes (SCA) as collectors can effectively enhance the floatability of molybdenite. In a previous study, SCA were found to have an excellent adsorption effect on the molybdenite [001] surface (MS001), but they exhibited no adsorption behavior on the molybdenite [100] surface (MS100). However, other studies have shown that SCA could adsorb on MS100. In this paper, the underlying cause of this contradictory conclusion was identified by molecular dynamics simulation. The results show that SCA could adsorb both MS001 and MS100. However, at low SCA dosages, SCA have a strong interaction with MS001 but desorb quickly on MS100. This leads to the selective adsorption of SCA on MS001. As SCA’s concentration gradually increases, the selective adsorption behavior of SCA on MS001 will be disrupted. Excessive SCA concentration will lead to its adsorption at MS100. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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18 pages, 4376 KiB

Open AccessArticle

Activation of Peroxymonosulfate by Chrysotile to Degrade Dyes in Water: Performance Enhancement and Activation Mechanism

by Ying Dai, Qian Peng, Kun Liu, Xuekun Tang, Muyang Zhou, Kun Jiang and Binnan Zhu

Minerals 2021, 11(4), 400; https://doi.org/10.3390/min11040400 - 10 Apr 2021

Cited by 11 | Viewed by 3036

Abstract

An environmentally friendly activation method of peroxymonosulfate (PMS) provides a promising advanced oxidation processes for the degradation of organic wastewater. In this article, chrysotile, extracted from asbestos tailings, was found to be a kind of one-off catalyst relying on hydroxyl groups to activate PMS. Furthermore, the activation performance of the chrysotile had been greatly improved by the mean of calcining at 850 °C (850CC). It is worth mentioning that 850CC could not only realize three effective cycles, but also the mineralization ratio of Rhodamine B (RhB) could be impressively higher than 60%. According to characterization results, it was discovered that the chrysotile had transformed into forsterite with a fibrous morphology after calcination at 850 °C due to the loss of hydroxyl groups and the recombination of silicon, oxygen and magnesium atoms. Besides, the main active species produced by 850CC activating PMS were singlet oxygen and sulfate radicals. Further studies uncovered that PMS was successfully activated by a large number of unsaturated coordination oxygen on 850CC surface, and the activation mechanism was further elucidated. This study provides a new route for the comprehensive utilization of chrysotile and a valuable strategy for the degradation of hazardous organic pollutants in wastewater by PMS activation. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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15 pages, 18726 KiB

Open AccessArticle

Probing the Effect of Water Recycling on Flotation through Anion Spiking Using a Low-Grade Cu–Ni–PGM Ore: The Effect of NO₃⁻, SO₄²⁻ and S₂O₃²⁻

by Mathew Dzingai, Malibongwe S. Manono and Kirsten C. Corin

Minerals 2021, 11(4), 340; https://doi.org/10.3390/min11040340 - 25 Mar 2021

Cited by 10 | Viewed by 2549

Abstract

Water scarcity necessitates the recycling of process water within mineral processing practices. This may however come with its disadvantages for unit operations such as froth flotation as this process is water intensive and sensitive to water chemistry. It is therefore important to monitor the water chemistry of the recycle stream of process water and any other water source to flotation. Monitoring the concentrations of the anions in recycled process water is therefore important to consider as these are speculated to impact flotation performance. Batch flotation tests were conducted using synthetically prepared plant water (3 SPW) with a TDS of 3069 mg/L as the baseline experiment. 3 SPW contained 528 mg/LNO₃⁻ and 720 mg/L SO₄²⁻, other anions and cations, and no S₂O₃²⁻. Upon spiking 3 SPW with selected anions, viz, NO₃⁻, SO₄²⁻ and S₂O₃²⁻, it was noted that NO₃⁻ and SO₄²⁻ exhibited threshold concentrations while S₂O₃²⁻ did not show a threshold concentration for both copper and nickel grade. Spiking 3 SPW with 352 mg/L more of NO₃⁻ to a total 880 mg/L NO₃⁻ concentration resulted in the highest copper and nickel grade compared to 3 SPW while increasing the S₂O₃²⁻ from 60 to 78 mg/L increased nickel and copper grade. 720 to 1200 mg/L SO₄²⁻ and 528 to 880 mg/L NO₃⁻ were deemed the concentration boundaries within which lies the threshold concentration above which flotation performance declines with respect to metal grades, while for S₂O₃²⁻ the threshold concentration lies outside the range considered for this study. Anion distribution between the pulp and the froth did not seem to impact the recovery of copper or nickel. Notably, the correlation between the concentrate grades and anion distribution between the froth and the pulp seemed to be ion dependent. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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15 pages, 8853 KiB

Open AccessArticle

Effect of Ferric Ions on Sulfidization Flotation of Oxidize Digenite Fine Particles and Their Significance

by Jiwei Xue, Dawei Ren, Sen Wang, Xianzhong Bu, Zhenguo Song, Chen Zhao and Tong Chen

Minerals 2021, 11(3), 305; https://doi.org/10.3390/min11030305 - 16 Mar 2021

Cited by 4 | Viewed by 1937

Abstract

Digenite fine particles are easily oxidized and ferric ions (Fe³⁺) commonly exist in the flotation pulp of digenite. This study investigated the effect of Fe³⁺ on the sulfidization flotation of oxidized digenite fine particles using sodium butyl xanthate (SBX) as a collector. The results of microflotation experiments show that the flotation rate and recovery of oxidized digenite fine particles can be improved by adding Na₂S and SBX, whereas the existence of large amounts of Fe³⁺ is not beneficial for the sulfidization flotation of digenite. The results of Fe³⁺ adsorption, zeta potential, and contact angle measurements indicate that Fe³⁺ can be adsorbed on the digenite surface mainly in the form of Fe(OH)₃, which hinders the adsorption of SBX and significantly reduces the surface hydrophobicity of digenite. X-ray photoelectron spectroscopy analysis further suggests that the poor surface hydrophobicity of digenite in the presence of Fe³⁺ is due to the production of large amounts of hydrophilic iron and copper oxides/hydroxides on the surface. Furthermore, optical microscopy analysis shows that these hydrophilic species effectively disperse digenite fine particles in the pulp, which eventually leads to the poor floatability of digenite. Therefore, it is necessary to reduce the amount of Fe³⁺ present in the pulp and adsorbed on digenite surface before sulfidization to realize effective separation of oxidized digenite fine particles and iron sulfide minerals. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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14 pages, 2173 KiB

Open AccessArticle

Effect of Dodecane-Oleic Acid Collector Mixture on the Evolution of Wetting Film between Air Bubble and Low-Rank Coal

by Yinfei Liao, Xingwei Song, Maoyan An, Zhe Yang, Xiaodong Hao and Hourui Ren

Minerals 2021, 11(1), 58; https://doi.org/10.3390/min11010058 - 10 Jan 2021

Cited by 8 | Viewed by 2297

Abstract

The wetting film evolution process is essential for flotation, especially in bubble–particle attachment. A mixed collector has been proved effective in promoting flotation. In this paper, the effect of a mixed collector (MC) composed by n-dodecane (D) and oleic acid (OA) on wetting film evolution was investigated using the extended Derjagin–Landau–Verwey–Overbeek (EDLVO) theory, the Stefan–Reynolds model, induction time, and zeta potential measurement. The hydrophobic force constant between bubble and coal treated by different collectors was analyzed. The results showed that MC was superior in reducing the induction time and increasing the zeta potential. When bubbles interacted with coal treated by MC, they had relatively low interaction energy, high critical film thickness, and high drainage rate. The order of hydrophobic force constant was no reagent < D < OA < MC. It indicated that the hydrophobic interaction between bubbles and coal particles treated by MC was the strongest because of the synergistic effect of D and OA. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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11 pages, 2678 KiB

Open AccessArticle

Comparative Studies on Flotation Performance of Saturated Fatty Acids and Unsaturated Fatty Acids Separated from Hogwash Oil

by Wenda Guo, Yujie Cai, Yimin Zhu, Yanjun Li and Yongsheng Sun

Minerals 2021, 11(1), 50; https://doi.org/10.3390/min11010050 - 6 Jan 2021

Cited by 3 | Viewed by 2440

Abstract

Low flotation recovery, high pulp temperature, and large dosage of reagents are the typical disadvantages when using mixed fatty acids (MFA) prepared from hogwash oil for flotation directly. To determine the type of fatty acid that yields poor flotation performance, flotation performance and adsorption characteristics of saturated fatty acids (SFA) and unsaturated fatty acids (UFA) separated from the MFA were studied in our work. GC-MS, FT-IR, iodine value detection and melting point measurement showed that UFA contained –(CH=CH–CH₂)_n- groups and had much lower melting point. Quartz flotation tests were used to compare the flotation performance of UFA and SFA, which showed that UFA had excellent low-temperature floatability, and the flotation recovery of UFA was 35 percentage points higher than that of SFA at 20 °C and pH = 11.5. Zeta potential, FT-IR and XPS analysis indicated that UFA and SFA could adsorb onto the surface of activated quartz through chemisorption and hydrogen bonding. However, the adsorption of UFA was much stronger and more favorable; thus, the reason MFA have poor flotation performance was the presence of SFA. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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12 pages, 5025 KiB

Open AccessArticle

The Influence Mechanism of Magnesium Ions on the Morphology and Crystal Structure of Magnetized Anti-Scaling Products

by Yubin Wang, Xinyu Mao, Wei Xiao and Wangbo Wang

Minerals 2020, 10(11), 997; https://doi.org/10.3390/min10110997 - 10 Nov 2020

Cited by 4 | Viewed by 3378

Abstract

Magnetization technology has been widely used in various transportation pipeline anti-scaling and descaling processes due to its simple equipment, low operating cost and low secondary pollution. To resolve structural pipeline issues in concentrations, the effects of magnesium salt concentration on conductivity, pH value and calcium ion concentration of a magnetized calcium chloride sodium bicarbonate mixed solution were studied. The results indicated that 4.0% MgSO₄ had the greatest anti-scaling effect under dynamic water conditions, which increased the calcium concentration of the mixed solution by 5.93%. Furthermore, the synergistic effects of 5.0% magnesium carbonate on the scaling of calcium carbonate were the largest, which reduced the calcium concentration of the mixed solution by 22.19%. Scanning electron microscope (SEM) and Raman spectra showed that magnesium carbonate reduced the effects of magnetization because it inhibited the formation of vaterite-type calcium carbonate and promoted the formation of calcite-type calcium carbonate. Magnesium sulfate can improve the anti-scaling effects of magnetization because it promotes the formation of vaterite calcium carbonate with high solubility. The results of this study can provide a theoretical basis for the scaling process and dissolution behavior regulation of calcium carbonate and have an important reference significance for scale prevention and scale removal in concentrator pipelines. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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17 pages, 4893 KiB

Open AccessArticle

Adsorption Behavior and Wettability of Rhodochrosite Surface: Effect of C₁₈ Fatty Acid Unsaturation

by Zhihui Shen, Qin Zhang, Xianbo Li and Qianlin Chen

Minerals 2020, 10(10), 905; https://doi.org/10.3390/min10100905 - 12 Oct 2020

Cited by 13 | Viewed by 2920

Abstract

Mineral surface wettability and its regulation by the adsorption of collectors have an important influence on the flotation performance. The adsorption behavior of C₁₈ fatty acid with different unsaturation and its effect on rhodochrosite wettability was investigated with surface tension, contact angle, and atomic force microscopy (AFM) measurements. The results indicated that rhodochrosite hydrophobicity increased with the increasing concentration of fatty acid, along with the maximum contact angle (θ_max) between hemimicelle concentration (HMC) and critical micelle concentration (CMC). Oleic acid (OA), linoleic acid (LA), and α-linolenic acid (ALA) had a higher θ_max than stearic acid (SA), but the value decreased with the increase of C=C bond number. Besides, preferential adsorption of unsaturated fatty acids on the liquid-air interface can be attributed to the molecule’s steric hindrance resulting from C=C double bond, and the θ kept almost invariant with a higher value of Γ_LG than Γ_SL until HMC. The oriented monolayer and bilayer structure of fatty acids formed gradually on rhodochrosite surface with increasing concentration. However, the θ_max may not necessarily correspond to the beginning of bilayer formation. Cylindrical monolayer and bilayer micelles of SA molecules were observed on rhodochrosite surface at HMC and CMC, respectively. While bilayer structures of unsaturated fatty acids formed before complete coverage of monolayer on rhodochrosite surface because of surface heterogeneity. This work provided a good understanding on the adsorption mechanism of fatty acid on rhodochrosite for flotation. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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