Efficient and selective recovery of rhenium (Re) from complex acidic media remains challenging because of its low concentration and interference from coexisting impurities. In copper smelting waste acid, Re is usually present at a trace level, whereas arsenic and silicon are present at much higher concentrations, thereby complicating selective Re enrichment and downstream purification. To address this issue, we designed and synthesized N1,N1,N6,N6-tetrapentylhexane-1,6-diamine (THD), a novel diamine extractant with spatially separated amine sites, for the selective extraction of perrhenate (ReO4-). Density functional theory (DFT) calculations were performed using trioctylamine (TOA), trihexylamine (THA) and N1,N1,N2,N2-tetrapentylethane-1,2-diamine (TED) as reference extractants. The results indicated that THD possesses more favorable protonation characteristics and stronger electrostatic and thermodynamic affinity toward ReO4-. In the real waste-acid system, THD exhibited superior Re extraction performance and selectivity. At the extractant concentration of 100 mmol/L and pH 0.6, the Re extraction efficiency reached 95%, outperforming TOA, THA and TED. Meanwhile, the co-extraction of As and Si remained limited (<15%). The loaded Re was efficiently stripped using aqueous ammonia, and the extraction system maintained stable performance over ten extraction-stripping cycles. Kinetic, thermodynamic, Fourier transform infrared spectroscopy (FTIR) and electronic-structure analyses revealed that Re extraction by THD is a spontaneous exothermic process governed by protonation-driven ion-association mechanism. The high performance of THD originates from the favorable electronic environment of its spatially separated amine sites and the directional N–H⋯O interactions between protonated THD and ReO4-. This work provides molecular-level guidance for designing efficient diamine extractants for Re recovery from acidic waste streams.

This study investigates the mechanism of novel amidoxime-based collectors --4-pyridylamidoxime (PA), 3ethyl-4-pyridylamidoxime (EPA), and 3-methyl-5-tert-butyl-4-pyridylamidoxime (MBPA) in the flotation separation of wolframite from gangue minerals (calcite and quartz). Through a combination of theoretical simulations with flotation experiments, the structure-activity relationship and selective adsorption mechanism of these collectors are systematically revealed. The results indicate that the ionic form of collectors exhibit higher reactivity, with MBPA demonstrating the most favorable electron-donating capacity and its molecular electrostatic potential of -0.223 eV. Density functional theory (DFT) calculations indicate that MBPA forms strong covalent bond-dominated adsorption on wolframite (0 2 0) surface, medium-strength polar covalent adsorption on quartz (1 0 1) surface, and must overcome a significant adsorption energy barrier on calcite (1 0 4) surface. This comprehensively explains the selectivity order (wolframite > quartz > calcite) at the mechanistic level. Flotation experiments demonstrate that MBPA achieved a high wolframite recovery of 86.77 % without the need for activators, significantly higher than that of calcite (16.51 %) and quartz (27.11 %). FT-IR spectroscopy further confirmed its chemical adsorption on wolframite surfaces. This study provides an efficient collector for wolframite flotation and offers theoretical insights and new strategies for flotation reagents design.

Molybdenum (Mo) is susceptible to entrainment in certain copper-bearing ores. However, the Mo element in the copper concentrate is lost in the copper slag after undergoing the pyrometallurgical process. Basic research for recovering the Mo from the copper slag is of high meaning, however, being rarely investigated. Herein, with the assistance of Cu as the alloying agent, high-efficiency recovery of Mo is realized by the in-situ generated metal Fe during the reduction of the copper slag. The redistribution of Mo during the pyrometallurgical process of copper concentrate is firstly investigated. Then, reduction of the copper slag is systematically investigated, including the optimization for the amounts of added CaO and reductant as well as reaction temperature. Under the optimized conditions, 76 % Mo in the slag can be recovered by in-situ forming a FeMo alloy bulk, containing 0.4 wt% Mo. Interestingly, when the metal Cu is added for assisting the Mo capture, the Mo recovery can be further increased to 87 % by forming the Fe-Cu-Mo alloy, with the Mo grade being also increased to 0.6 wt% in the alloy. Also, the reaction temperature can be decreased from 1450 degrees C to 1400 degrees C, contributing to a more mild reaction condition. Moreover, when the flotation tailing of smeling copper slag is used as the raw materisla, 98 % of the trace-content Cu (similar to 0.26 %) in the flotation tailing of the smeling slag can be also enriched in the Fe-Cu-Mo alloy. The results can provide new insights for the comprehensive recovery of trace valuble critical metals from the copper slags.

Formation of silica gel during hydrometallurgical processing is notorious for severely impeding the filtration of ore slurry, rendering the extraction of valuable metals from high-silicon ores extremely difficult. However, high-silicon resources are highly abundant on earth, being typical refractory ores. For example, zinc oxide ore, bauxite, high-silicon phosphate rock, and metallurgical slags are all silicon-rich resources. Understanding the gel formation mechanism and developing novel strategies to enhance the filtration performance are very crucial for propelling the industrial extraction of valuable elements from high-silicon ores. In this review, the importance for utilization of silicon-rich ores is firstly discussed. Then, the transformation chemistry of silicon-containing species in solutions is summarized. Importantly, the strategies for improving filtration performance of high-silicon ore pulps are systematically categorized and discussed in detail for the first time, as we know. Finally, the industrial application status of these strategies and the future prospects are presented. The contents can hopefully provide some insights for surmounting the filtration challenges during the hydrometallurgical extraction of value metals from high-silicon refractory ores and slags.

ABSTRACT As typical commercial cathodes, the large‐scale application of LiMn 2 O 4 (LMO) is restricted by poor structural stability, severe Mn dissolution, and high‐purity Mn precursors with relatively high cost. Herein, the novel waste‐to‐resource strategy is proposed to prepare high‐entropy LMO, along with considerable economic and environmental value. Used electrolytic zinc anode slime (EZAS) as raw material, a selective leaching‐coprecipitation process is developed to prepare multielement‐doped MnO 2 precursors, further converted into a series of high‐entropy LMO materials with configurational entropies ranging from 0 to 3.29 J mol −1 K −1 . Moreover, the key entropy window (∼0.59 J mol −1 K −1 ) is identified, where suitable doping behaviors induces lattice expansion, and elevates Mn 4+ ratio to suppress Jahn–Teller distortion, accompanied with the reinforcing of Mn─O framework. Supported by detailed ex situ/in situ exploring, the stabilization of the electrode‐electrolyte interface is revealed, meanwhile, the detrimental phase transformations are successfully suppressed. Thus, the as‐optimized sample achieved a capacity of 126.77 mAh g −1 at 0.1 C, and even 84.50% capacity retention after 400 cycles at 3.0 C. A closed‐loop recycling system, including diverse Mn‐based waste, AI, and entropy engineering, is proposed to sustainably regenerate high‐entropy LMO cathodes. This work is anticipated to provide a closed‐loop recycling system toward high‐performance cathodes, illustrating the high‐entropy physical‐chemical effect of LiMn 2 O 4 .

In industrial zinc electrodeposition using ZnSO4-H2SO4 electrolyte, Cu2+ impurities must be strictly limited below 0.5 mg/L, making real-time detection critical. However, the extremely high concentrations of Zn2+ (similar to 45 g/L) and H2SO4 (similar to 150 g/L) in the electrolyte induce significant instability in detection materials upon contact. Herein, we developed a novel electrochemical sensor: an AgNWs-GO/FTO electrode, fabricated by modifying fluorine-doped tin oxide (FTO) substrates with AgNWs-GO nanocomposites (graphene oxide-doped silver nanowires) via simple physical mixing and casting. This sensor enables rapid, accurate, and sensitive detection of Cu2+ in zinc electrolytes. Compared to AgNWs/FTO electrodes (without GO), the AgNWs-GO/FTO electrode exhibits a significantly broader linear range, improved repeatability, 1.76-fold higher sensitivity, and a lower detection limit. Its accuracy was validated against results from the standard inductively coupled plasma-atomic emission spectroscopy (ICP-AES) method. Physicochemical analyses and theoretical calculations reveal that the enhanced performance stems from interactions between GO and AgNWs, where chemical bonds formed via oxygen-containing groups (C-O and C=O) likely facilitate electron transfer, strengthen Cu2+ binding affinity, and improve electrode stability. This work provides a reliable sensing platform for trace impurity monitoring in harsh industrial electrolytes, with implications for optimizing zinc electrodeposition processes.

Aqueous zinc-ion batteries (ZIBs) are promising for large-scale energy storage but are severely limited by zinc dendrite growth and interfacial side reactions. Inspired by the strong zinc-affinity of flotation collectors, a trace amount of ethyl xanthate was introduced into a ZnSO4 electrolyte to regulate zinc electrochemistry. Ethyl xanthate molecules significantly alter the solvation structure of Zn2+ ions and undergo specific adsorption on the electrode surface. This synergistic regulation markedly reduces the interfacial concentration gradient of Zn2+ ions and decreases the population of electrochemically active water molecules at the electrode surface, thereby effectively suppressing zinc dendrite growth and the hydrogen evolution side reaction. Consequently, the Zn//Cu half-cell exhibits stable cycling for 1894 h at 3 mA cm− 2, while the Zn//Zn symmetric cell maintains stable cycling for 1337 h at 2 mA cm− 2. This work provides a mineral-processing-inspired strategy for stabilizing zinc metal anodes.

Molybdenum dioxide (MoO2), as a transition metal oxide, possesses advantages such as high specific capacity, ease of synthesis, and environmental friendliness, making it a popular choice for lithium-ion battery anode materials. However, its application in lithium-ion batteries is constrained by severe volume expansion and low electrical conductivity. This work utilized bitumen as a carbon source, leveraging its solubility characteristics in organic solvents of varying polarity to enhance the mechanical properties of the carbon coating layer, thereby preparing Hept-MoO2NP electrodes nano-indentation characterization revealed that the carbon coating exhibits a low Young's modulus, high fracture toughness and excellent elasticity, enhancing the overall structural stability of the anode material. Relaxation time distribution analysis of the AC impedance results further confirmed that the carbon coating effectively suppresses impedance increase during cycling, thereby improving cycling stability. After 100 cycles at a current density of 200 mA g-1, the Hept-MoO2NP electrode exhibited a reversible specific capacity of (742.3 +/- 18.6) mAh g-1, markedly outperforming unmodified solvent-regulated carbon-coated MoO2 electrode materials. This study provides an effective strategy for designing high-performance MoO2 anode materials, offering significant reference value for enhancing the energy density and cycle life of lithium-ion batteries.

This study used a simple liquid-phase chemical reduction method (green synthesis method) to synthesize ultrafine copper powder, with CuSO4 & sdot;5H2O as the copper source, ascorbic acid as the reducing agent, and environmentally friendly STPP as a protective agent. By adjusting pH, STPP dosage, and temperature, spherical copper powders with particle sizes of 0.91-2.60 mu m were obtained. EDS, FT-IR, contact angle, and Zeta potential analyses revealed STPP's role in forming Cu-STPP complexes, adsorbing on the copper surface, and regulating dispersibility and morphology. The reduction mechanism of the system was further clarified. This work provides a feasible route for green synthesis of ultrafine copper powders with narrow size distribution and uniform morphology, and offers a methodological basis for environmentally friendly preparation of other spherical powders.

Graphite nanosheets with highly oriented conductive coatings have been developed to guide uniform zinc deposition in aqueous zinc-ion batteries (ZIBs). By leveraging mechanical ball milling and chemical functionalization, hydroxyl and carboxyl groups are grafted onto graphite nanosheets. The graphite nanosheets' slurry is coated on copper foil using shear force, ensuring the coating thickness is smaller than the graphite nanosheet diameter to promote horizontal alignment, which contributes to the formation of the (002)-oriented structure of the conductive coating. The resulting Cu@C current collector exhibits enhanced hydrophilicity and abundant zincophilic sites from rich oxygen-containing groups, promoting uniform Zn2+ distribution around the anode and guiding Zn2+ uniform transport along the (002) plane and zinc epitaxial growth. Structural characterization confirms the formation of two-dimensional, highly oriented graphite nanosheets on the copper substrate. Electrochemical tests reveal that Zn||Cu@C asymmetric cells achieve outstanding cycling stability and high Coulombic efficiency over thousands of cycles at various current densities, while Zn||Cu cells suffer from dendrite formation and rapid performance decay. Full cells with MnO2 cathodes further demonstrate improved capacity, rate performance, and charge-transfer kinetics when paired with Cu@C anodes. This work provides a practical strategy for crystal-plane-guided zinc deposition, offering insights into the design of long-life and high-performance zinc-ion batteries.

Production of one ton of metal copper results in 2.2 tons of slag, which contains 8 %-12 % Fe3O4. The solid Fe3O4 particles greatly increases the viscosity of molten slag, which retard the in-situ settling of copper-containing phases, making the severe entrainment of copper in slag (generally 0.7 %-5 % Cu). Also, the high hardness of Fe3O4 increases the energy consumption of grinding for further copper recovery from the solidified slag. Highefficient reduction of Fe3O4 in molten slag is the key for the economic reclamation of copper resource in the slag. Herein, using the mixture of FeS2 and carbon as the high-efficient reductant (HER), the Fe3O4 content in slag is substantially decreased from 12.4 % to 5.6 %, contributing to the increase of copper recovery from 65.26 % to 71.82 % based on open-circuit flotation process, with the copper concentrate being upgraded from 19.39 % to 26.85 % simultaneously. More importantly, the elimination of Fe3O4 facilitates to the decrease of grinding energy from 27.67 kWh/t to 18.53 kWh/t. The analysis based on SEM-EDS, TIMA-X, XPS and FactSage results reveal that the efficient elimination of Fe3O4 contribute to decreased encapsulation degree of Cu-containing phases by hard Fe3O4 particles (from 45.9 % to 12 %), reduced slag viscosity (from 5 Pa & sdot;s to 1.5 Pa & sdot;s), and enlarged Cucontaining particles (from 7.63 mu m to 29.5 mu m in average size), conjointly contribute to enhanced copper recovery and decreased energy consumption. The results can provide new insights for deep recovery of copper from the slag.

Ultrafine tungsten-rhenium (W-Re) alloy powders are indispensable materials in many high-end realms. However, the conventional synthesis processes face the problems of high synthesis temperature and huge Re loss. Herein, solution combustion followed by a four-stage temperature-programmed hydrogen reduction is suggested, which lower the synthesis temperature from 1000 degrees C to 800 degrees C and decrease the Re loss from 2 % to 0.1 %, with the W-Re powders presenting very homogeneous composition and nanoscale size at the same time. This method significantly improved the preparation efficiency of ultrafine W-Re alloy powder and the utilization efficiency of rhenium element. By employing a combination of various characterization techniques and theoretical calculations, the fundamental mechanism underlying low-temperature, high-efficiency reduction was elucidated: evaporation of crystal water (200 degrees C), ReO3 reduction (400 degrees C), W18O49 reduction (600 degrees C) and complete reduction of residual oxides (800 degrees C). The results can provide new insights for high-yield preparation of W-Re powders at mild conditions.

In this work, high-valence rhenium (Re) was firstly used as the dopant to improve the optical and transparent thermal properties of Cs0.33WO3. Among all samples, the film with 2 mol% Re doping exhibited the best transparent thermal insulation performance, with a luminous transmittance (Tlum) of 53.5 % and a near-infrared (NIR) shielding efficiency (Psi NIR) of 70.1 %. Structural and spectroscopic analyses revealed that Re6 + successfully substituted for W6+ in the hexagonal lattice, inducing the formation of W5+ species and oxygen vacancies. These defect states enhanced the free carrier concentration and promoted small polaron absorption, thereby improving the NIR shielding performance. The improved transparency was also attributed to enhanced hydrophilicity and particle dispersion. The results highlighted the potential of high-valence Re doping as an effective strategy to modulate the electronic structure and defect chemistry of Cs0.33WO3, providing a new pathway for the design of advanced energy-saving smart window coatings.

Hundreds of millions of tons of copper slags are produced, occupying a large number of land by stockpiling and leading to loss of valuable elements such as copper, zinc, and iron in the slag. Using hydrometallurgical leaching by sulfuric acid (H2SO4) to extract these elements from copper slag enables resource recovery and reduces slag volume, attracting widespread attention. However, copper slag can contain up to similar to 25 % silicon oxide (SiO2), which forms silica gel that complicates filtration. Additionally, the leaching efficiency of valuable elements is not satisfactory. Herein, a combined approach is suggested, involving 60 % H2SO4 curing for suppressing silica gel formation and ultrasonic enhancement for leaching valuable elements. Under optimal conditions, the silica dissolution rate decreased from 32.30 % to 3.44 %, and the filtration rate increased from 9.71 L/(hm(2)) to 179.62 L/(hm(2)). After ultrasonication, the leaching efficiency of copper, zinc, and iron increased from 32.13 %, 52.07 %, and 56.23 % to 88.12 %, 79.72 %, and 72.02 %, respectively. Thermodynamic calculations combined with compositional analysis suggest that generated FeSO4 and the exothermic nature of the system conjointly suppresses silica gel formation during the curing process. The cavitation effect of the ultrasound contributes to the promoted leaching efficiency of valuable metals. The results can provide new insights for comprehensive utilization of copper slags and other high-silicon secondary resources.

Ultrafine silver powder, valued for its superior physicochemical properties, faces production challenges including high costs and difficult wastewater treatment in conventional liquid-phase reduction synthesis. To address these issues, this study develops an innovative sulfate-mediated process. The key strategy involves precipitating silver ions from a silver nitrate solution as a silver sulfate intermediate by adding sulfuric acid, which effectively separates nitrate ions from subsequent processing steps and establishes a closed-loop nitrate recycling system. Furthermore, this strategy allows sulfate ions to serve dual functions during the reduction stage, acting as both anionic regulators and protective agents, thereby eliminating the need for organic protective agents and reducing production cost. A theoretical model establishing the relationship between particle size and reaction time was derived and experimentally validated, enabling precise control of silver powder size from 0.82 to 1.45 mu m. An integrated wastewater treatment system was implemented, which removes sulfate ions via calcium oxide precipitation and recovers ammonia with an efficiency of 95.0 % by air stripping and absorption. This process yields recyclable ammonia water and a readily biodegradable effluent. A comprehensive comparison of the traditional process and the sulfate-mediated process for the production of 100 kg of silver powder indicates that the sulfate-mediated process has reduced the chemical reagent costs by 22.4 % and significantly simplifies wastewater management. The resulting sub-micron silver powder exhibits excellent thermal stability (weight loss <0.5 % up to 1000 degrees C) and a high tap density (4.5 g & centerdot;cm(-3)). These results underscore the strong potential of this method for sustainable industrial applications of silver powders.

The efficient recovery of electrode materials from spent lithium iron phosphate (S-LFP) batteries via froth flotation is often hindered by the presence of hydrophobic polyvinylidene fluoride (PVDF) binder on cathode surfaces, which masks their intrinsic wettability. In this work, bio-based glutamic acid (Glu) was used as a selective depressant to achieve flotation separation between LFP cathodes and graphite anodes. In single-mineral flotation tests, the recovery rates of PVDF-coated LFP (P-LFP) and graphite reached 88.55% and 94.4%, respectively. Flotation experiments on actual spent electrode mixtures achieved an S-LFP recovery of 90.13% with a grade of 90.07%, while graphite recovery reached 86.84% with a grade of 90.24%. Contact angle and zeta potential measurements demonstrate that Glu selectively adsorbs on the S-LFP surface, supporting our hypothesis that Glu selectively interacts with S-LFP rather than graphite. FT-IR and XPS analyses confirm the chemical interaction between Glu and the PVDF layer on the S-LFP, while FBRM results reveal improved dispersion of S-LFP particles. This selective depression mechanism, based on differences in chemical adsorption, provides a more economical and environmentally sustainable strategy for the recovery of cathode and anode materials.

Density functional theory (DFT) is employed to investigate the oxidation and flotation reagent adsorption mechanisms on the marcasite surface, aiming to elucidate the underlying interfacial reactions at the atomic scale. The results indicate that the marcasite (0 1 0) surface is the most stable plane. O-2 is observed to dissociate on the marcasite surface, binding separately to the Fe and S sites, and ultimately yielding oxidation products such as FeSO4 and SOx2- species. The Fe-Fe hollow site on the marcasite (0 1 0) surface is identified as the optimal active site for collector adsorption, with the adsorption strength following the order: xanthate > dithiophosphate > dithiocarbamate. Lime (as CaOH+) and cyanide (CN-) exhibit stronger adsorption on the marcasite surface than sodium hydroxide (OH-) and sodium sulfide (HS-). The Ca2+ ion in lime plays a significant role in this depression performance. This study elucidates the oxidation pathway and reagent interaction mechanisms of marcasite at the atomic and electronic levels, thereby providing a theoretical foundation for its flotation separation and interfacial regulation.

Gold (Au) is a strategically critical metal whose technological relevance and increasing demand contrast with the long-term decline in primary ore grades. This review discusses gold recovery from primary ores providing the metallurgical and technological baseline for the comparative evaluation of unconventional Au-bearing resources. Emphasis is placed on electronic waste and copper anode slimes as highly valuable secondary raw materials containing gold concentrations comparable to, or exceeding, those in natural deposits. The review examines the origin, chemical and mineralogical characteristics, impurity profiles, and processing routes associated with these materials, including conventional and emerging pyro-, hydro-, and biometallurgical approaches. Material-specific constraints, matrix complexity, recovery efficiency, process limitations, and environmental aspects are discussed in relation to process applicability and technological feasibility. Particular attention is given to the differences between geologically constrained primary ores and heterogeneous secondary Au-bearing materials, whose engineered and continuously evolving compositions influence recovery strategies, limiting the direct application of conventional routes to secondary resources. Finally, the review highlights that primary ores remain the dominant source of global Au production, whereas secondary resources currently represent a complementary component, and outlines key challenges and future directions relevant to the broader utilization of these materials.

Talc is a layered silicate mineral with pronounced crystal anisotropy, consisting of a basal (001) surface and an edge (100) surface, which complicates its separation from valuable minerals. In this study, tannic acid (TA) was used as a depressant, and its adsorption behaviors on the two representative surfaces of talc-silica (basal plane surface) and magnesium silicate (edge surface)-were systematically investigated using experimental methods and molecular simulations. TA addition reduced the contact angles of the talc basal and edge surfaces by 30.5 degrees and 22.7 degrees, respectively, indicating enhanced hydrophilicity. ToF-SIMS analysis revealed that TA physically adsorbs onto the silica surface, while both physical and chemical interactions occur on the magnesium silicate surface. AFM showed lumpy adsorbate on the silica surface and point-like adsorbate on the magnesium silicate surface, with a greater roughness change observed for the former. QCM-D measurements confirmed that TA formed a multilayer flexible adsorbate on the silica surface and a dense, rigid monolayer on the magnesium silicate surface. Molecular dynamics simulations further revealed that van der Waals interactions dominated TA adsorption on the (001) surface, while electrostatic interactions prevailed on the (100) surface. These findings provide insight into the selective depression mechanism of talc and offer guidance for the depression of other layered silicate minerals.

Introducing a conductive carbon layer between the copper foil current collector and silicon active material effectively mitigates electrode damage and battery capacity loss caused by uneven silicon expansion. In this study, a low-cost, environmentally friendly carbon-coated copper foil (CCF) is designed using zeolitic imidazolate framework 8-derived carbon (ZPC) as the carbon source, polyethylenepyrrolidone (PVP) as the binder, and deionized water as the solvent. The large surface area and porosity of ZPC effectively accommodate the volume expansion of silicon, thereby enhancing the overall performance of the battery. The bare copper foil electrode experiences rapid decay, with a failure occurring after just 75 cycles at 0.5 C. In contrast, the CCF electrode maintains a reversible capacity of 576.8 mAh/g even after 200 cycles. The CCF electrode demonstrates superior specific capacity and cycle stability in both the rate and cycling test. According to the relaxation time distribution (DRT) analysis, the porous carbon layer on the CCF surface ensures excellent electrical contact between silicon and the Cu foil during cycling, facilitates uniform lithium insertion into silicon, prevents uncontrolled growth of the SEI layer, and guarantees stable battery operation. This CCF preparation process provides a promising solution to mitigate the degradation of battery performance caused by silicon expansion.