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13 pages, 1854 KiB

Open AccessArticle

Uranium(VI), Thorium(IV), and Lanthanides(III) Extraction from the Eudialyte Concentrate Using the N,O-Hybrid Heterocyclic Reagents

by Alfiya M. Safiulina, Alexey V. Lizunov, Alexey V. Ivanov, Nataliya E. Borisova, Petr I. Matveev, Sergey M. Aksenov and Dmitry V. Ivanets

Metals 2025, 15(5), 494; https://doi.org/10.3390/met15050494 - 29 Apr 2025

Abstract

N,O-donor hybrid heterocyclic extractants have great potential for separation of actinides from lanthanides in spent nuclear fuel reprocessing processes. We demonstrate that this type of reagents can be used for primary concentration of actinides contained in eudialyte, a promising mineral containing a heavy [...] Read more.

N,O-donor hybrid heterocyclic extractants have great potential for separation of actinides from lanthanides in spent nuclear fuel reprocessing processes. We demonstrate that this type of reagents can be used for primary concentration of actinides contained in eudialyte, a promising mineral containing a heavy group of lanthanides. With respect to lanthanide ions, the efficiency of their extraction decreases in the series L3 >> L1 > L2, and the extraction of actinides decreases in the series L1 ≈ L3 >> L2. For the extractant L2 based on 2,2′-bipyridine-6,6′-dicarboxylic acid diamide, the efficiency of lanthanide purification from U, Th exceeds 50. The structure and stereochemical features of the ligands do not have a significant effect on the composition of the formed complexes. The solvation numbers are close to 1 for all range f-elements studied, except for thorium, which indicates the predominant formation of complexes with the composition ratio of 1:1. The solvation numbers 1.4–1.5 are observed for thorium(IV), and the established values indicate the formation of a mixture of complexes with the composition ratios of 1:1 and 2:1. Full article

(This article belongs to the Special Issue Advances in Mineral Processing and Hydrometallurgy—3rd Edition)

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16 pages, 4917 KiB

Open AccessArticle

Effect of Lead in Antimony and Tin Dissolution from Recycled Lead–Acid Battery Dross in Hydrobromic Acid Solution

by Arturo Hirata-Miyasaki and Corby G. Anderson

Metals 2025, 15(4), 356; https://doi.org/10.3390/met15040356 - 24 Mar 2025

Viewed by 444

Abstract

Demand and prices for antimony have increased over the last few years. Recycling supplied 15% of domestic consumption in the US, while the remaining 85% was imported. Hydrometallurgical processes have long used alkaline sulfide systems and hydrochloric acid, closing doors on new approaches. [...] Read more.

Demand and prices for antimony have increased over the last few years. Recycling supplied 15% of domestic consumption in the US, while the remaining 85% was imported. Hydrometallurgical processes have long used alkaline sulfide systems and hydrochloric acid, closing doors on new approaches. Bromine compounds have been recently used to recover PGMs and REEs successfully; thus, antimony leaching with bromine compounds is theoretically feasible. This research was conducted to develop a viable technology for hydrobromic acid between 50 °C and 70 °C as a leaching reagent on dross through single- and two-stage leaching using design of experiment (DoE) and adding sustainability to current industrial processes while minimizing waste products in recycling processes. The preliminary results showed that bromine, specifically hydrobromic acid, can be used as a leaching reagent for antimony dissolution. By decreasing the lead content in the solids and increasing the concentration, temperature, and reaction time, antimony leaching from the dross was increased from 20% to 50%. The findings, coupled with acid regeneration, can be implemented as an alternative to other reagents in industrial plants. Full article

(This article belongs to the Special Issue Advances in Mineral Processing and Hydrometallurgy—3rd Edition)

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16 pages, 4337 KiB

Open AccessArticle

Innovative Methods for Intensifying the Processing of Zinc Clinker: Synergy of Microwave Treatment and Ultrasonic Leaching

by Bagdaulet Kenzhaliyev, Tatiana Surkova, Ainur Berkinbayeva, Zhazira Baltabekova, Kenzhegali Smailov, Yerkezhan Abikak, Shynar Saulebekkyzy, Nazerke Tolegenova, Tursynkul Omirbek and Zamzagul Dosymbaeva

Metals 2025, 15(3), 246; https://doi.org/10.3390/met15030246 - 25 Feb 2025

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Abstract

This study presents an innovative approach to processing refractory zinc-bearing clinker through the synergistic application of microwave thermal treatment and ultrasonic-assisted leaching. Microwave irradiation induces phase transformations in the clinker, improving its reactivity and facilitating subsequent zinc dissolution, while ultrasonic cavitation enhances mass [...] Read more.

This study presents an innovative approach to processing refractory zinc-bearing clinker through the synergistic application of microwave thermal treatment and ultrasonic-assisted leaching. Microwave irradiation induces phase transformations in the clinker, improving its reactivity and facilitating subsequent zinc dissolution, while ultrasonic cavitation enhances mass transfer by disrupting passivation layers. Key process parameters, including acid concentration, temperature, pulp density, and leaching time, were systematically investigated using response surface methodology (RSM) and central composite design (CCD). The results demonstrate that the optimized process conditions led to a significant increase in zinc recovery from refractory materials. Full article

(This article belongs to the Special Issue Advances in Mineral Processing and Hydrometallurgy—3rd Edition)

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20 pages, 5115 KiB

Open AccessArticle

Gold Leaching from an Auriferous Ore by Alkaline Thiosulfate–Glycine–Copper Solution

by Alex S. Redrovan, Ernesto de la Torre and Carlos F. Aragón-Tobar

Metals 2025, 15(2), 204; https://doi.org/10.3390/met15020204 - 14 Feb 2025

Cited by 1 | Viewed by 1169

Abstract

The thiosulfate–glycine–copper system has emerged as a promising alternative for gold recovery, offering significant advantages over cyanidation and ammoniacal thiosulfate leaching. Recognizing the limitations of thiosulfate degradation in ammoniacal systems, this study focused on optimizing the thiosulfate–glycine–copper system for gold recovery using an [...] Read more.

The thiosulfate–glycine–copper system has emerged as a promising alternative for gold recovery, offering significant advantages over cyanidation and ammoniacal thiosulfate leaching. Recognizing the limitations of thiosulfate degradation in ammoniacal systems, this study focused on optimizing the thiosulfate–glycine–copper system for gold recovery using an auriferous ore with (10 g t⁻¹) of Au. The ore was associated with aluminosilicates such as grossular (64%) and clinochlore (12%). Leaching conditions were systematically varied, including thiosulfate (0.5–1 M), glycine (0.3–1.75 M), copper sulfate (2–10 mM), pH (9.3–10.5), temperature (20–60 °C), 6 h, and potassium permanganate concentrations (0.004–0.04 M), and dosing intervals were also optimized. Thus, the best conditions were thiosulfate (0.7 M), glycine (1.75 M), copper sulfate (5 mM), pH 9.3, 60 °C, and permanganate addition every 2 h. This system achieved 89.3% gold recovery in just 6 h, comparable to cyanidation (89.8% in 24 h) and ammoniacal thiosulfate (58% in 6 h), but without generating toxic effluents, such as in the cyanidation process. Additionally, a gold dissolution mechanism was proposed, highlighting glycine’s role in stabilizing cupric ions and enhancing thiosulfate efficiency. This study underscores the thiosulfate–glycine–copper system as a sustainable and effective method for gold recovery. Full article

(This article belongs to the Special Issue Advances in Mineral Processing and Hydrometallurgy—3rd Edition)

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14 pages, 3169 KiB

Open AccessCommunication

Innovative Process for Strategic Metal Recovery from Electric Arc Furnace Slag by Alkaline Leaching

by Nour-Eddine Menad, Alain Seron and Sara Bensamdi

Metals 2024, 14(12), 1364; https://doi.org/10.3390/met14121364 - 29 Nov 2024

Viewed by 1140

Abstract

Currently, Electric Arc Furnace Slag (EAFS) is undervalued and is therefore only used in road construction, while blast furnace slag (BFS) is used as an interesting alternative in construction materials to replace natural aggregates in the manufacture of concrete. Steel slag (SS) represents [...] Read more.

Currently, Electric Arc Furnace Slag (EAFS) is undervalued and is therefore only used in road construction, while blast furnace slag (BFS) is used as an interesting alternative in construction materials to replace natural aggregates in the manufacture of concrete. Steel slag (SS) represents a promising secondary resource due to its high content of critical metals, such as chromium (Cr) and vanadium (V). These metals are essential for various strategic industries, making it crucial to consider slag as a resource rather than waste. However, the primary challenge lies in selectively recovering these valuable metals. In this work, we explore the development of a hydrometallurgical process aimed at efficiently extracting Cr and V from Electric Arc Furnace Slag (EAFS). The characterization of the investigated EAFS shows that the main crystalline phases contained in this heterogeneous material are srebrodolskite, larnite, hematite, and spinel such as probably magnesio-chromite. The targeted metals seem to be dispersed in various mineral species contained in the SS. An innovative hydrometallurgical method has been explored, involving physical preparation by co-grinding slag with alkaline reagents followed by treatment in a microwave furnace to modify the metal-bearing species to facilitate metal processing dissolution. The results obtained showed that the leaching rates of Cr and V were, respectively, 100% and 65% after 15 min of treatment in the microwave furnace, while, after 2 h of conventional heat treatment, as explored in a previous study, 98% and 63% of the Cr and V were, respectively, leached. Full article

(This article belongs to the Special Issue Advances in Mineral Processing and Hydrometallurgy—3rd Edition)

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19 pages, 4693 KiB

Open AccessArticle

Effect of Nickel Impurities in Pyrite on Catalytic Degradation of Thiosulfate

by Xuecong Qin, Tao Zhang, Wenhua Qin and Hongbo Zhang

Metals 2024, 14(11), 1256; https://doi.org/10.3390/met14111256 - 5 Nov 2024

Viewed by 922

Abstract

The effects of nickel content in nickel-bearing pyrite on photocatalytic properties, light absorption properties, and oxidative decomposition of thiosulfate were studied. The leaching experiments show that the consumption of thiosulfate in the Cu²⁺-ethylenediamine (en)-S₂O₃²⁻ system increases with [...] Read more.

The effects of nickel content in nickel-bearing pyrite on photocatalytic properties, light absorption properties, and oxidative decomposition of thiosulfate were studied. The leaching experiments show that the consumption of thiosulfate in the Cu²⁺-ethylenediamine (en)-S₂O₃²⁻ system increases with an increase in nickel content in nickel-bearing pyrite. The consumption of Cu(en)₂²⁺ initially increases and then decreases with an increase in leaching time. There is a clear correlation between the change trend in its consumption and the doping amount of nickel in pyrite. The XPS results show that in the Cu²⁺-ethylenediamine (en)-S₂O₃²⁻ leaching gold system (temperature 25 °C, time 35 h, solution: 0.1 mol/L S₂O₃²⁻, 5 mmol/L Cu(en)₂²⁺, 200 mL solution), the nickel of pyrite-containing nickel can be transferred to the leaching solution and becomes nickel ion. In this leaching system, Cu(II), which was originally complexed with en, is reduced to Cu(I) in a short time. The consumption of Cu(en)₂²⁺ increased rapidly in the 5 h period and then decreased gradually after 5 h. The results showed that the presence of free Ni²⁺ in the solution facilitated the conversion of bivalent copper ions to monovalent copper ions. Free Ni²⁺ ions can compete with Cu²⁺ ions for en ligands. When ethylenediamine complexes with Ni²⁺, the decomposition of Cu(en)₂²⁺ into Cu(en)⁺ and en occurs more rapidly. And the en, which was originally to be oxidized with Cu(en)⁺ to form Cu(en)₂²⁺, forms Ni(en)₂²⁺. As a result, the concentration of Cu(en)₂²⁺ continues to decrease in a short period of time. Full article

(This article belongs to the Special Issue Advances in Mineral Processing and Hydrometallurgy—3rd Edition)

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21 pages, 10386 KiB

Open AccessArticle

Microscopic Simulation of RE³⁺ Migration in Ion-Type Rare Earth Ores Based on Navier–Stokes Equation—Exchange Reaction—Ion Migration Coupling

by Dan Wang, Fuyu Wu, Yunzhang Rao, Zhilian Zhao, Wei Xu and Min Han

Metals 2024, 14(10), 1130; https://doi.org/10.3390/met14101130 - 4 Oct 2024

Cited by 1 | Viewed by 861

Abstract

In the in-situ leaching method of ionic rare earth, ion exchange reaction between rare earth ions and leaching agent ions is carried out, which allows the rare earth ions to be leached from the ore body as the leaching solution flows through the [...] Read more.

In the in-situ leaching method of ionic rare earth, ion exchange reaction between rare earth ions and leaching agent ions is carried out, which allows the rare earth ions to be leached from the ore body as the leaching solution flows through the pores. This indicates that the leaching process of rare earth ions is closely related to the seepage field, ion exchange field, and ion migration process of the leaching solution. In this study, an ionic rare earth mine located in Longnan of Jiangxi Province was taken as the research object. By conducting nuclear magnetic resonance scanning on the ore samples of this mine and vectorizing the nuclear magnetic resonance images, a two-dimensional geometric model of pores was obtained. Then, COMSOL Multiphysics software was used to establish a coupled numerical model of seepage–exchange–migration of the ionic rare earth mine during the leaching process at the pore scale to study the seepage situation of leaching solution with different injection strengths and concentrations, as well as the exchange and migration process. The results show that increasing the concentration of magnesium ions can increase the difference of ion diffusion concentration, accelerate the forward exchange rate of ions, promote the forward exchange reaction, and improve the concentration gradient of rare earth ions in the leaching solution. The more significant the diffusion effect, the higher the ion migration rate, while at the same time inhibiting the reverse adsorption of rare earth ions, and accelerating the leaching efficiency of rare earth ions. In addition, increasing the strength of the injection solution allows rare earth ions to leach out of the ore body earlier, shortens the leaching cycle, and thus reduces the peak concentration of leached rare earth ions. By analyzing the effects of the strength of the injection solution and leaching concentration on ionic rare earth leaching, the influence of those two factors on engineering economy can be briefly evaluated, which can be provided as a reference for the optimization of ionic rare earth mining technology. Full article

(This article belongs to the Special Issue Advances in Mineral Processing and Hydrometallurgy—3rd Edition)

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Review

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35 pages, 20196 KiB

Open AccessReview

Mineralogy of Deep-Sea Manganese Nodules and Advances in Extraction Technology of Valuable Elements from Manganese Nodules

by Xu Wang, Wenqing Qin, Maolin Li, Xueduan Liu, Yangrui Cheng, Shiping Chen and Congren Yang

Metals 2024, 14(12), 1359; https://doi.org/10.3390/met14121359 - 28 Nov 2024

Viewed by 1478

Abstract

The vast seabed holds tremendous resource potential that can provide necessary materials for future human societal development. This study focuses on the mineralogy of seafloor manganese nodules off the coast of China in the Western Pacific and the primary techniques for extracting valuable [...] Read more.

The vast seabed holds tremendous resource potential that can provide necessary materials for future human societal development. This study focuses on the mineralogy of seafloor manganese nodules off the coast of China in the Western Pacific and the primary techniques for extracting valuable metal elements from manganese nodules. The research indicates that the main valuable metal elements in the manganese nodules from this region include Cu, Co, Ni, Mn, Fe, etc. The key to extracting these valuable metals lies in reducing Mn(IV) to Mn(II) to disrupt the structure of the nodules, thereby releasing the valuable elements. The extraction processes for the main valuable metal elements of manganese nodules are mainly divided into two categories: pyrometallurgical–hydrometallurgical and solely hydrometallurgical. In order to cope with the challenges of environmental change and improve utilization efficiency, bioleaching, hydrogen metallurgy, and co-extraction are gaining increasing attention. For promoting commercialization, the future development of manganese nodule resources can refer to the technical route of efficient short-process extraction technology, the comprehensive recovery of associated resources, and tail-free utilization. Full article

(This article belongs to the Special Issue Advances in Mineral Processing and Hydrometallurgy—3rd Edition)

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11 pages, 231 KiB

Open AccessReview

Recent Advances in Indium Recovery

by Francisco Jose Alguacil

Metals 2024, 14(11), 1282; https://doi.org/10.3390/met14111282 - 12 Nov 2024

Viewed by 1877

Abstract

Though indium has been removed from the fifth list (2023) of critical raw materials for the European Union list of critical metals, its recovery is still of paramount importance due to its wide use in a series of high-tech industries. As its recovery [...] Read more.

Though indium has been removed from the fifth list (2023) of critical raw materials for the European Union list of critical metals, its recovery is still of paramount importance due to its wide use in a series of high-tech industries. As its recovery is closely associated with zinc mining, the recycling of In-bearing wastes is also of interest, for both profitable and environmental reasons. With unit operations (in hydrometallurgy and pyrometallurgy or extractive metallurgy) playing a key role in the recycling of indium, the present work reviewed the most recent innovations (2024) regarding the use of these operations in the recovery from this valuable metal from different solid or liquid wastes. Full article

(This article belongs to the Special Issue Advances in Mineral Processing and Hydrometallurgy—3rd Edition)

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