Research

11 pages, 3472 KiB

Open AccessArticle

Efficient Extraction of Lithium from Calcined Kaolin Lithium Clay with Dilute Sulfuric Acid

by Wenlin Zhong, Lang Yang, Feng Rao, Liangzhou Tong and Haipeng Feng

Minerals 2024, 14(4), 359; https://doi.org/10.3390/min14040359 - 29 Mar 2024

Viewed by 558

In this study, the structure and phase transition of kaolin lithium clay at different calcination temperatures were studied and discussed; subsequently, the effects of Li leaching with sulfuric acid under various factors were investigated in detail. The experimental results indicated that an optimal [...] Read more.

In this study, the structure and phase transition of kaolin lithium clay at different calcination temperatures were studied and discussed; subsequently, the effects of Li leaching with sulfuric acid under various factors were investigated in detail. The experimental results indicated that an optimal Li leaching rate of 81.1% could be achieved when kaolin lithium clay was calcined at 600 °C for 1 h, followed by leaching with 15.0% sulfuric acid at 80 °C for 2 h. The TG-DSC, XRD, and SEM analyses showed that the layered structure of the clay was not destroyed during the leaching and calcination processes. During the process of calcination, kaolinite was converted to metakaolinite via dehydroxylation. During the process of leaching, the Al on the surface of the metakaolinite was dissolved by sulfuric acid, resulting in the destruction of the Al-O structure; then, Li⁺ was exchanged for H⁺ to the surface of the mineral and entered the solution under the action of diffusion. The leaching kinetics showed that the leaching process was controlled by a diffusion model, and the activation energy (E_a) was 41.3 kJ/mol. The rapid extraction of Li from calcined kaolin lithium clay with sulfuric acid leaching offers a high-efficiency, low-energy-consumption strategy for the utilization of new lithium resources. Full article

(This article belongs to the Special Issue Recent Advances in Extractive Metallurgy)

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15 pages, 2215 KiB

Open AccessArticle

Soft Measurement of Rare Earth Multi-Element Component Content Based on Multi-LightVGG Modeling

by Zhen Li, Jun Xiao, Qihan Zhang, Kunming Liu and Jinhui Li

Minerals 2023, 13(12), 1491; https://doi.org/10.3390/min13121491 - 28 Nov 2023

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Abstract

The current hardware equipment used to detect the content of each element component in the rare earth extraction process has a complex structure and high maintenance cost. A modeling method for the soft measurement of rare earth multi-element component content is proposed to [...] Read more.

The current hardware equipment used to detect the content of each element component in the rare earth extraction process has a complex structure and high maintenance cost. A modeling method for the soft measurement of rare earth multi-element component content is proposed to address this issue. This method uses the Multi-LightVGG multi-tasking learning model and the Multi Gradient Descent Algorithm based on Optimized Upper Bound (MGDA-OUB) to optimize the model for each prediction task and find the Pareto optimal solution. After conducting several experiments, the Multi-LightVGG model loaded with MGDA-OUB has lower MRE, RMSE for Pr, Nd prediction, and MAX(|error|) for Nd prediction than the Multi-LightVGG model without MGDA-OUB by 0.3778%, 0.5208%, 0.0015, 0.0015, and 0.1985%, respectively; and the MRE and RMSE of the Multi-LightVGG model for Pr and Nd prediction under the same optimization conditions are lower than those of Multi-ResNet18 by 0.3297%, 0.5423%, 0.0019, and 0.002, respectively, thus indicating that MGDA-OUB can effectively solve multiple task-specific Pareto solutions to avoid possible conflicts between specific tasks, while the Multi-LightVGG model, compared to the Multi-Resnet18 model, has a backbone network that can effectively capture the abstract representations in the images of the rare earth-extraction mixed solution, which in turn improves the prediction accuracy of the content of each elemental component. Full article

(This article belongs to the Special Issue Recent Advances in Extractive Metallurgy)

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17 pages, 4876 KiB

Open AccessArticle

Removal of Aluminum from Synthetic Rare Earth Leach Solution by Selective Complexation and Turbidity Point Extraction

by Liang Gao, Yan Wang, Jian Oyang, Yang Gao, Jinbiao Liu, Ruixiang Wang, Zhifeng Xu and Jinhui Li

Minerals 2023, 13(12), 1462; https://doi.org/10.3390/min13121462 - 22 Nov 2023

Viewed by 791

Abstract

During the leaching process of ion-adsorbed rare earth ores, large amounts of non-rare earth impurities such as aluminum and iron will be generated. This study selected glutamic acid as a complex agent to selectively calculate aluminum ions; then, added non-ionic surfactants and extract [...] Read more.

During the leaching process of ion-adsorbed rare earth ores, large amounts of non-rare earth impurities such as aluminum and iron will be generated. This study selected glutamic acid as a complex agent to selectively calculate aluminum ions; then, added non-ionic surfactants and extract and separate aluminum ions from a rare earth solution using the cloud point extraction method. The effects of solution pH, reaction temperature, equilibration time, amount of glutamic acid, reaction time, and amount of Triton X-114 on aluminum extraction were investigated. The results showed that with a M_glu:M_Al ratio of 3:1, a solution pH of 4.5, a constant temperature of 40 °C, and the addition of 10 mL Triton X-114 after 10 min of reaction time, the single extraction efficiency of aluminum ions reached 78.01%, and the extraction efficiency of rare earths was only 5.09% after 10 min of equilibration time. The reaction equation of glutamic acid with aluminum ions was determined, and the lowest extraction concentration of aluminum ions in the glutamic acid complexation extraction solution was found to be c_Al = 0.045 ± 0.003 g/L, with a separation coefficient of β(Al/RE) = 66.15. This result indicated that the aluminum ions in the mixed solution could be effectively separated from the rare earth ions when using glutamic acid as a complexing agent in combination with the turbidity point extraction method. Full article

(This article belongs to the Special Issue Recent Advances in Extractive Metallurgy)

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16 pages, 9665 KiB

Open AccessArticle

Changing the Pulp Properties and Surface Hydrophilicity of Galena and Pyrite by Selecting the Appropriate Grinding Media Towards Their Selective Separation

by Qilin Zhai, Runqing Liu, Jia Li, Wei Sun and Yuehua Hu

Minerals 2023, 13(9), 1213; https://doi.org/10.3390/min13091213 - 15 Sep 2023

Cited by 2 | Viewed by 797

Abstract

The grinding process plays a crucial role in the floatability of mineral. The present study proposes a scheme to assist in the flotation separation of galena and pyrite by optimizing the choice of grinding media. The effects of grinding media (cast iron balls, [...] Read more.

The grinding process plays a crucial role in the floatability of mineral. The present study proposes a scheme to assist in the flotation separation of galena and pyrite by optimizing the choice of grinding media. The effects of grinding media (cast iron balls, steel balls containing 18% chromium, and steel balls containing 12% chromium) on the pulp properties and hydrophilicity of galena and pyrite were evaluated using grinding tests, micro-flotation tests, X-ray photoelectron spectroscopy, and adsorption capacity analyses. The results showed significant differences in the pH, potential, and dissolved oxygen content of the galena or pyrite pulp with different grinding media, resulting in significant differences in the flotation behavior of galena and pyrite. The use of cast iron balls in the grinding process was more favorable for the flotation separation of galena and pyrite. The pyrite surfaces adsorbed less butyl xanthate when cast iron balls were used as grinding media due to the presence of more hydrophilic hydroxyl iron. Therefore, cast iron balls as grinding media are favorable for broadening the surface hydrophilic differences between galena and pyrite. Full article

(This article belongs to the Special Issue Recent Advances in Extractive Metallurgy)

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16 pages, 8240 KiB

Open AccessArticle

Comprehensive Utilization of Pyrite Concentrate Pyrolysis Slag by Oxygen Pressure Leaching

by Lin-Bo Liu, Longsheng Yi and Yunfeng Song

Minerals 2023, 13(6), 726; https://doi.org/10.3390/min13060726 - 25 May 2023

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Abstract

The preparation of high-purity sulfur and pyrrhotite by pyrolysis holds great potential to realize the high-value utilization of pyrite concentrate (FeS₂), i.e., a by-product during the flotation of sulfide ore. In this study, the pyrrhotite obtained from the pyrolysis of pyrite [...] Read more.

The preparation of high-purity sulfur and pyrrhotite by pyrolysis holds great potential to realize the high-value utilization of pyrite concentrate (FeS₂), i.e., a by-product during the flotation of sulfide ore. In this study, the pyrrhotite obtained from the pyrolysis of pyrite concentrate was taken as the study object, and the effects of acid types, initial acidity, leaching time, leaching temperature, oxygen pressure, and liquid-to-solid ratio on the leaching behavior of pyrrhotite under oxygen pressure, were explored. The results show that elemental sulfur and hematite-based iron residue can be obtained by oxygen pressure leaching of pyrrhotite. It is found that the optimal experimental conditions for pyrrhotite oxygen pressure leaching are hydrochloric acid with 0.8 mol/L of initial acidity, 5 h of leaching time, 0.8 MPa of oxygen partial pressure, and 9:1 of liquid to solid ratio at 150 °C; moreover, the yield of sulfur reached 88.37%. Under optimal conditions, the leaching ratios of Fe, Pb, and Zn were 19.8%, 92.25%, and 99.11%, respectively. The sieved leaching residue was roasted at a low temperature of 500 °C, where the grade of Fe in the obtained hematite iron powder was 61.46%, and the grades of Pb, Zn, and S were 0.082%, 0.024%, and 0.1%. Clearly, the results meet well with the standard of the first grade of pyrite cinder, and this process realizes the comprehensive recovery of Fe and S resources in pyrolysis slag, which provides a superb technical route for the high-value utilization of pyrite concentrate. Full article

(This article belongs to the Special Issue Recent Advances in Extractive Metallurgy)

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24 pages, 10362 KiB

Open AccessArticle

Silver(I) Recovery by Ion Flotation Process from Aqueous Solutions in Cells with Spargers

by Laura P. Ángeles Palazuelos, Mizraim U. Flores Guerrero, Miguel Pérez Labra, Iván A. Reyes Domínguez, Ramiro Escudero García, Francisco Patiño Cardona, Francisco R. Barrientos Hernández, Julio C. Juárez Tapia and Martín Reyes Pérez

Minerals 2023, 13(4), 572; https://doi.org/10.3390/min13040572 - 19 Apr 2023

Cited by 1 | Viewed by 1074

Abstract

Extractive metallurgy has recently turned its attention to waste treatment for the recovery of precious metals through innovative metallurgical processes, such as ion flotation. This work studied the influence of several chemical and physical factors, such as the concentration of xanthate [x], frother [...] Read more.

Extractive metallurgy has recently turned its attention to waste treatment for the recovery of precious metals through innovative metallurgical processes, such as ion flotation. This work studied the influence of several chemical and physical factors, such as the concentration of xanthate [x], frother agent [e], dithiophosphate [xl], pH, superficial gas velocity Jg, percentage of gas holdup Eg, bubble diameter (Db) calculated with the drift flux model, and the type of sparger, in the efficiency of silver(I) recovery by the ion flotation technique in sub-aerated cells. The results obtained indicate a 90.7% v/v recovery of silver(I) under conditions of 3.77 × 10⁻⁴ M [x], 1.25 × 10⁻⁴ M [e], Jg 0.5 cm/s, Jl 0.19 cm/s, Eg of 4.1% v/v, and Optimal Db of 0.11 cm, with a rigid bubble generator, achieving an apparent flotation kinetics of 4.16 1/min. The use of combinations [x]–[xl] achieve a silver(I) recovery of 86.9% with a Jg of 1.0 cm/s. The best recovery efficiencies achieved 93% w/w silver(I) are with pH 8.0, [e] of 1.25 × 10⁻⁴, Jl of 0.19 (cm/s) and a rigid sparger compared to a flexible one. Full article

(This article belongs to the Special Issue Recent Advances in Extractive Metallurgy)

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16 pages, 5508 KiB

Open AccessArticle

A Novel Dissolution and Synchronous Extraction of Rare Earth Elements from Bastnaesite by a Functionalized Ionic Liquid [Hbet][Tf₂N]

by Yukun Huang, Dasong Wang, Zhuo Duan, Jiang Liu, Yijun Cao and Weijun Peng

Minerals 2022, 12(12), 1592; https://doi.org/10.3390/min12121592 - 12 Dec 2022

Cited by 4 | Viewed by 2077

Abstract

Rare earth elements (REEs) are widely used in high-tech industries and are important basic raw materials. Bastnaesite is one of the most important minerals used in the rare earth extraction industry, and the efficient development of it is the key guarantee for the [...] Read more.

Rare earth elements (REEs) are widely used in high-tech industries and are important basic raw materials. Bastnaesite is one of the most important minerals used in the rare earth extraction industry, and the efficient development of it is the key guarantee for the safe supply of rare earth raw materials. In this study, a novel method for dissolving bastnaesite using a carboxyl-functionalized ionic liquid ([Hbet][Tf₂N]) is proposed. This innovative method provides a collaborative model with the dissolution and synchronous extraction of rare earth elements during the heating and cooling of the [Hbet][Tf₂N]–H₂O system. In the heating process, rare earth elements can be dissolved in a weakly acidic environment of ionic liquid without the trouble of HF escaping, and the leaching efficiencies of rare earth elements are above 95%. During the cooling of the leaching system, the rare earth ions in the dissolved state are extracted into the ionic liquid phase due to the two-phase stratification of [Hbet][Tf₂N] and aqueous solution. It has been proved that rare earth ions recovery and ionic liquid regeneration can be achieved by back extraction using oxalic acid for the REEs-loaded ionic liquid. Full article

(This article belongs to the Special Issue Recent Advances in Extractive Metallurgy)

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14 pages, 5373 KiB

Open AccessArticle

Analysis of the Selective Flotation of Elemental Gold from Pyrite Using Diisobutyl Monothiophosphate

by Weiping Liu, Jan Dean Miller, Wei Sun and Yuehua Hu

Minerals 2022, 12(10), 1310; https://doi.org/10.3390/min12101310 - 17 Oct 2022

Cited by 5 | Viewed by 1541

Abstract

The gold contained in copper ores is an important resource for the gold industry. In some cases, elemental gold is present and can be recovered by selective flotation. It has been reported that the gold grade and recovery can be increased, without sacrificing [...] Read more.

The gold contained in copper ores is an important resource for the gold industry. In some cases, elemental gold is present and can be recovered by selective flotation. It has been reported that the gold grade and recovery can be increased, without sacrificing the copper recovery, by replacing AERO 3477 (diisobutyl dithiophosphate (DTP)) with AERO 7249 (mixture of diisobutyl monothiophosphate (MTP) and diisobutyl dithiophosphate (DTP)) as the main collector. The fundamental understanding of the improvement in selectivity with the addition of MTP in the flotation of elemental gold from pyrite is limited and is the subject of this paper. In this regard, the hydrophobicity and selectivity of DTP and MTP in the flotation of pyrite and gold are compared and discussed. Density functional theory (DFT) was used to examine the electron density, reactivity, highest occupied molecular orbital (HOMO), and lowest unoccupied molecular orbital (LUMO) of the MTP and DTP collectors. The interaction energies for the adsorption of MTP and DTP from fresh pyrite, oxidized pyrite and gold surfaces were calculated and discussed with respect to the experimental results reported in the literature. Molecular dynamics simulation (MDS) was used to examine the adsorption state of MTP and DTP on the pyrite (100) and Au (111) surfaces. Full article

(This article belongs to the Special Issue Recent Advances in Extractive Metallurgy)

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