Minerals

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13 pages, 3061 KiB

Open AccessArticle

Numerical Simulation of Gas–Liquid Two-Phase Flow CFD–PBM Model in a Micro–Nanobubble Generator

by Weiguang Xu, Wenjuan Li, Jianwei Wang, Yongsheng Song, Biao Wu, Jiankang Wen, Kaiguo Li and Bin Li

Minerals 2022, 12(10), 1270; https://doi.org/10.3390/min12101270 - 8 Oct 2022

Cited by 2 | Viewed by 1747

Abstract

A micro–nanobubble generator is the most critical component of micro–nano flotation equipment. Understanding the bubble generation characteristics in the generator plays a vital role in optimizing the performance of the device and improving the flotation of fine-grained minerals. In this study, to explore [...] Read more.

A micro–nanobubble generator is the most critical component of micro–nano flotation equipment. Understanding the bubble generation characteristics in the generator plays a vital role in optimizing the performance of the device and improving the flotation of fine-grained minerals. In this study, to explore the generation and evolution of bubbles in the micro–nanobubble generator of a cyclonic jet flotation cell, the flow field parameters of the gas–liquid two-phase flow inside the generator were solved using CFD–PBM combined with Luo’s population balance model. The internal bubble size was in the range of 0.99 μm to 140 μm. After the gas entered the generator from the suction pipe, it mainly moved in the center of the tube, and the diameter of the bubbles was relatively large at this time. With the bubble movement, large bubbles in the center were broken into small bubbles and then moved toward the periphery of the tube. Thereafter, the smaller-diameter bubbles gathered and formed large-diameter bubbles. The average diameter of the generated bubbles gradually increased from approximately 30 to 110 μm. Full article

(This article belongs to the Special Issue Progress of Reagents in Minerals Flotation)

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11 pages, 2362 KiB

Open AccessArticle

Low-Temperature Flotation Separation of Diaspore from Kaolinite by Using a Mixed Collector

by Xiaofei Man, Chenliang Wang, Shichao Yu, Xiaofeng Yang, Jianjun Liu, Yafeng Fu, Zhenhai Dong, Hui Zhi and Leming Ou

Minerals 2022, 12(7), 891; https://doi.org/10.3390/min12070891 - 15 Jul 2022

Cited by 1 | Viewed by 1310

Abstract

In this paper, the effect of a new mixed collector sodium oleate (NaOl)/tert dodecyl mercaptan (TDM) on the separation of diaspore and kaolinite at 283 K was investigated. The molar ratio of NaOl to TDM is 8:2. The properties of the mixed collector [...] Read more.

In this paper, the effect of a new mixed collector sodium oleate (NaOl)/tert dodecyl mercaptan (TDM) on the separation of diaspore and kaolinite at 283 K was investigated. The molar ratio of NaOl to TDM is 8:2. The properties of the mixed collector and its adsorption mechanism on diaspore and kaolinite were studied by surface tension measurements, Zeta potential determinations and XPS analysis. The flotation results show that the mixed collector NaOl/TDM has a good collection ability for diaspore and a good selectivity for kaolinite at low temperatures. Therefore, the mixed collector NaOl/TDM can effectively separate diaspore and kaolinite under alkaline conditions at 283 K. The results of surface tension measurements show that the molecular density, hydrophobic association ability and collection ability of the mixed collector NaOl/TDM are better than those of the single collector at 283 K. In addition, the formation of a micelle effect of the mixed collector NaOl/TDM has a synergistic effect, which improves the reagent activity at low temperatures with the flotation effect enhanced. The results of the Zeta potential determinations and XPS analysis show that the total adsorption capacity of the mixed collector NaOl/TDM on the surface of the diaspore at low temperatures is higher than that of NaOl, and the adsorption capacity on the surface of kaolinite is similar to that of NaOl. The mixed collector NaOl/TDM may be adsorbed on the surface of diaspore and kaolinite by a hydrogen bond at 283 K. Full article

(This article belongs to the Special Issue Progress of Reagents in Minerals Flotation)

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14 pages, 12608 KiB

Open AccessArticle

Flotation Performance and Adsorption Mechanism of a Novel Chelating Collector for Azurite

by Bo Hu, Lingyun Huang, Bo Yang, Xian Xie, Xiong Tong, Xiongrong Zhang and Xin Sun

Minerals 2022, 12(4), 441; https://doi.org/10.3390/min12040441 - 1 Apr 2022

Cited by 2 | Viewed by 2233

Abstract

Thiophosphate compounds have attracted much attention in coordination chemistry, but their deep adsorption mechanism remains underexplored as flotation collectors. The flotation performance and adsorption mechanism of a novel (dibutoxy-thiophosphorylsulfanyl)-acetic acid (CDDP) chelating collector on azurite surfaces were studied by micro-flotation tests, zeta potential [...] Read more.

Thiophosphate compounds have attracted much attention in coordination chemistry, but their deep adsorption mechanism remains underexplored as flotation collectors. The flotation performance and adsorption mechanism of a novel (dibutoxy-thiophosphorylsulfanyl)-acetic acid (CDDP) chelating collector on azurite surfaces were studied by micro-flotation tests, zeta potential measurements, and Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FE-SEM) analysis. The micro-flotation results indicated that CDDP exhibited superior collecting performances to direct flotation recovery of azurite and floated over 91.44% of azurite at pH 7. For sodium isopentyl xanthate (NaIX) and Benzohydroxamic acid (BHA) collectors, the addition of Na₂S still did not show good collection performance. The results of zeta potential, FTIR, XPS and FE-SEM measurements, all confirmed that CDDP showed a better affinity to azurite surfaces than NaIX and BHA. Furthermore, XPS and FE-SEM provided obvious evidence that CDDP could easily react with Cu²⁺ sites on azurite surfaces. Using the density functional theory (DFT) method, the collection capacity of azurite was CDDP > BHA > NaIX, which exactly matched the micro-flotation results. In addition, this study provided an atomic-scale understanding of the structure–property relationship of CDDP as chelating agents for copper mineral flotation. Full article

(This article belongs to the Special Issue Progress of Reagents in Minerals Flotation)

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11 pages, 2672 KiB

Open AccessArticle

Simultaneous Recovery of Niobium and Sulfur from Carbonate Niobite Ore with Flotation

by Shuang Liu, Lang Yang, Hao Yi and Shaoxian Song

Minerals 2022, 12(4), 432; https://doi.org/10.3390/min12040432 - 31 Mar 2022

Cited by 4 | Viewed by 1603

Abstract

Exploring new ways to acquire niobium resources is essential to resolve niobium supply risks, due to the fact that, at present, 99% of niobium is controlled by only two countries. In the present work, a flotation technique was applied to separate niobium from [...] Read more.

Exploring new ways to acquire niobium resources is essential to resolve niobium supply risks, due to the fact that, at present, 99% of niobium is controlled by only two countries. In the present work, a flotation technique was applied to separate niobium from low-grade niobite ore. To maximize the utilization of the original ore resources, pre-flotation was conducted to recover sulfur and eliminate the adverse effects of sulfide on niobite flotation. The obtained sulfur grade and recovery were 33.74% and 92.04%, respectively, and its concentration ratio was 40x. As for the niobite flotation, a closed-circuit experiment with one rougher flotation, three cleaner flotations, and two scavenger flotations was carried out to achieve the maximum niobite recovery. To further improve the niobite recovery, a leaching process with diluted HCl was employed; the final obtained Nb₂O₅ grade and recovery were 30.19% and 65.04%, respectively, and the concentration ratio reached 242x. Moreover, the economic evaluation implies that the flotation process can attract great positive interest. Full article

(This article belongs to the Special Issue Progress of Reagents in Minerals Flotation)

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10 pages, 7954 KiB

Open AccessArticle

Study of Reagent Scheme, Entrainment and Their Relationship in Chalcopyrite Flotation in the Presence of Bentonite and Kaolinite

by Guohua Gu, Jianghui Zhou, Shiya Du, Su Liao and Yanhong Wang

Minerals 2022, 12(2), 263; https://doi.org/10.3390/min12020263 - 18 Feb 2022

Cited by 1 | Viewed by 1739

Abstract

Entrainment has been considered as an important factor affecting clayey ore flotation. In this study, the effect of reagent dosage on chalcopyrite flotation in the presence of bentonite and kaolinite was investigated through entrainment. It was found that increasing the collector and frother [...] Read more.

Entrainment has been considered as an important factor affecting clayey ore flotation. In this study, the effect of reagent dosage on chalcopyrite flotation in the presence of bentonite and kaolinite was investigated through entrainment. It was found that increasing the collector and frother dosage had little influence on copper recovery in the presence of bentonite, but decreased the copper grade substantially, owing to the increase in entrainment. With regard to kaolinite, increasing the reagent dosage increased the copper grade prominently, due to the decrease in entrainment. The substantial variation was related to the different interactions between the reagent and different clay minerals. The smaller surface area and hydration property of bentonite made most of the reagent remain in the solution, facilitating high entrainment, while kaolinite, with its larger surface area, adsorbed most of the reagent, which decreased the entrainment. The results of this study suggest a guideline of controlling reagent scheme in clayey ore flotation, based on the specific structure and properties of different clay minerals. Full article

(This article belongs to the Special Issue Progress of Reagents in Minerals Flotation)

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12 pages, 8501 KiB

Open AccessArticle

Flotation Separation of Dolomite from Fluorapatite Using Sodium Dodecyl Benzene Sulfonate as the Efficient Collector under Low Temperature

by Huifang Zheng, Yingxin Chen, Xiaoqing Weng, Yanfeng Jin, Richard M. Kasomo and Shunfu Ao

Minerals 2022, 12(2), 228; https://doi.org/10.3390/min12020228 - 10 Feb 2022

Cited by 4 | Viewed by 1630

Abstract

Flotation is the most often employed process to achieve the selective removal of contaminants from the raw materials used in the manufacturing of phosphate fertilizer. However, sodium oleate (NaOL), as a typical collector, is ineffective because of its low collecting ability under low [...] Read more.

Flotation is the most often employed process to achieve the selective removal of contaminants from the raw materials used in the manufacturing of phosphate fertilizer. However, sodium oleate (NaOL), as a typical collector, is ineffective because of its low collecting ability under low temperature. As a result, developing and implementing feasible alternatives is critical for the long-term output of mines. In this study, sodium dodecyl benzene sulfonate (SDBS), a low-cost and freely soluble reagent under low temperature was used to examine its collecting ability and selectivity in a fluorapatite-dolomite system by means of single and artificially mixed minerals flotation. The adsorption mechanism was evaluated with the help of XPS analyses. The flotation results demonstrate that SDBS could float both fluorapatite and dolomite, but show a higher affinity towards fluorapatite instead of dolomite. Moreover, SDBS could preferred adsorb onto fluorapatite surface when fluorapatite and dolomite coexist. SDBS is more suitable than NaOL for satisfactory recovery of fluorapatite under low temperature in terms of the higher recovery obtained. The XPS analyses results demonstrate that the adsorption of SDBS on fluorapatite surface was more intensively as opposed to that on dolomite surface and Ca active sites on fluorapatite surface are supposed to be the main location for SDBS attachment. Full article

(This article belongs to the Special Issue Progress of Reagents in Minerals Flotation)

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16 pages, 2884 KiB

Open AccessArticle

The Inadvertent Activation of Silicate Minerals Flotation and Their Depression in Molybdenite Beneficiation

by Yu Miao, Tao Long, Jingjun Wang, Fu Lai, Weiran Zuo and Bao Guo

Minerals 2021, 11(11), 1296; https://doi.org/10.3390/min11111296 - 22 Nov 2021

Viewed by 1726

Abstract

The Wushan Operation has been studied as a case study, particularly relevant to the copper-molybdenum separation circuit, in which efforts have been made to improve the quality of the molybdenum concentrate through diagnostic analysis. A key finding has been the appearance of coarser [...] Read more.

The Wushan Operation has been studied as a case study, particularly relevant to the copper-molybdenum separation circuit, in which efforts have been made to improve the quality of the molybdenum concentrate through diagnostic analysis. A key finding has been the appearance of coarser silicate minerals in the molybdenum concentrate due to their inadvertent activation in flotation. The suitable silicate minerals flotation conditions occurs, most likely, due to upstream bulk flotation regarding the usage of novel collectors and metal cations bearing process water. The flotation of silicate minerals can be diminished by the implementation of water glass and regrinding. The mechanisms underlying flotation behaviors have been revealed by using advanced in-situ surface analysis and particle size analysis techniques. Full article

(This article belongs to the Special Issue Progress of Reagents in Minerals Flotation)

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16 pages, 7018 KiB

Open AccessArticle

Molecular Dynamics Study on the Leaching of Zinc-Bearing Dust Sludge by Choline Chloride-Malonic Acid

by Jinxia Zhang, Chao Yang, Fusheng Niu, Shuling Gao and Jiajing Dong

Minerals 2021, 11(10), 1080; https://doi.org/10.3390/min11101080 - 30 Sep 2021

Cited by 7 | Viewed by 1734

Abstract

Molecular dynamics of the interaction between four metal oxides (ZnO, Fe₂O₃, Al₂O₃, and CaO) present in zinc-bearing dust sludge and choline chloride (ChCl)-malonic acid (MA)(1:2) was studied in this work using Materials Studio software. The [...] Read more.

Molecular dynamics of the interaction between four metal oxides (ZnO, Fe₂O₃, Al₂O₃, and CaO) present in zinc-bearing dust sludge and choline chloride (ChCl)-malonic acid (MA)(1:2) was studied in this work using Materials Studio software. The interaction mechanism was revealed by analyzing the interaction energy and radial distribution function from the perspective of quantum mechanics, and the simulation results were verified by single factor leaching experiments. The calculation results show that the complete cleavage surface of the four metal oxides is the (001) surface, and ChCl-2MA forms a stable structure with multiple intermolecular hydrogen bonds centered on the chlorine atom. The dynamic simulation of the interaction model shows that strength of interaction between ChCl-2MA and the four metal oxides follows the order: ZnO > Fe₂O₃ > Al₂O₃ > CaO. ChCl-2MA mainly interacts with ZnO by chemical adsorption, while ChCl-2MA mainly interacts with Fe₂O₃, Al₂O₃, and CaO by physical adsorption. The radial distribution function shows that Cl in ChCl-2MA and C=O in MA form chemical bonds with Zn in ZnO, and the choline cation (Ch⁺) forms C-H···O with ZnO. Among these bonds, the Cl-Zn bond energy is stronger. During the interaction between ChCl-2MA and Fe₂O₃ and Al₂O₃, O-H···O and C-H···O are formed and interact with CaO by van der Waals force. Single factor leaching experiments show that, under the same leaching conditions, the leaching rate of ZnO by ChCl-2MA is greater than 90%, while the leaching rate of Fe₂O₃, Al₂O₃, and CaO is about 10%. These results indicate good selectivity of ChCl-2MA for ZnO in the zinc-bearing dust sludge. The above conclusions have important theoretical significance and provide an in-depth understanding of the leaching mechanisms of zinc-bearing dust sludge in deep eutectic solvents. Full article

(This article belongs to the Special Issue Progress of Reagents in Minerals Flotation)

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