Additive manufacturing (AM) technology has emerged as a viable solution for manufacturing complex- shaped WC−Co cemented carbide products, thereby expanding their applications in industries such as resource mining, equipment manufacturing, and electronic information. This review provides a comprehensive summary of the progress of AM technology in WC−Co cemented carbides. The fundamental principles and classification of AM techniques are introduced, followed by a categorization and evaluation of the AM techniques for WC−Co cemented carbides. These techniques are classified as either direct AM technology (DAM) or indirect AM technology (IDAM), depending on their inclusion of post-processes like de-binding and sintering. Through an analysis of microstructure features, the most suitable AM route for WC−Co cemented carbide products with controllable microstructure is identified as the indirect AM technology, such as binder jet printing (BJP), which integrates AM with conventional powder metallurgy.

The water-quenched (WQ) 2195 Al−Li alloy was subjected to stretching at different temperatures, from room temperature (RT) to −196 °C (CT), to investigate the effect of cryogenic deformation on the aging precipitation behaviors and mechanical properties. The precipitation kinetics of the T1 phase and the microstructures in peak aging state were investigated through the differential scanning calorimetric (DSC) tests and electron microscopy observation. The results show that −196 ℃ deformation produces a high dislocation density, which promotes the precipitation of the T1 phase and refines its sizes significantly. In addition, the grain boundary precipitates (GBPs) of −196 °C-stretched samples are suppressed considerably due to the high dislocation density in the grain interiors, which increases the ductility. In comparison, the strength remains nearly constant. Thus, it is indicated that cryogenic forming has the potential to provide the shape and property control for the manufacture of critical components of aluminum alloys.

A series of leaching and electrochemical experiments were conducted to elucidate the critical role of hydrogen sulfide (H₂S) in copper-driven reduction of chalcopyrite. Results demonstrate that in the absence of H₂S, metallic copper converts chalcopyrite into bornite (Cu₅FeS₄). However, the introduction of H₂S promotes the formation of chalcocite (Cu₂S) by altering the oxidation pathway of copper. Electrochemical analysis demonstrates that the presence of H₂S significantly reduces the corrosion potential of copper from 0.251 to −0.223 V (vs SHE), reaching the threshold necessary for the formation of Cu₂S. Nevertheless, excessive H₂S triggers sulfate reduction via the reaction of 8Cu+H₂SO₄+3H₂S=4Cu₂S+4H₂O (ΔG=−519.429 kJ/mol at 50 °C), leading to inefficient copper utilization.

To synergistically recover alumina and alkali from red mud (RM), the structural stability and conversion mechanism of hydroandradite (HA) from hydrogarnet (HG) were investigated via the First-principles, XRF, XRD, PSD and SEM methods, and a novel hydrothermal process based on the conversion principle was finally proposed. The crystal structure simulation shows that the HA with varied silicon saturation coefficients is more stable than HG, and the HA with a high iron substitution coefficient is more difficult to be converted from HG. The (110) plane of Fe₂O₃ is easier to combine with HG to form HA, and the binding energy is 81.93 kJ/mol. The effects of raw material ratio, solution concentration and hydrothermal parameters on the conversion from HG to HA were revealed, and the optimal conditions for the alumina recovery were obtained. The recovery efficiencies of alumina and Na₂O from the RM are 63.06% and 97.34%, respectively, and the Na₂O content in the treated RM is only 0.13%.

Ceramic matrix composites (CMCs) are regarded as promising high-temperature materials for industrial applications due to their exceptional properties at elevated temperatures. However, their limited manufacturability restricts their capability to be produced as complex, large-scale structural components. Ni-based superalloys are well-known for their outstanding performance under high-temperature conditions. The integration of these two material types to create hybrid components can significantly broaden their applications in engineering. A critical challenge arises from the interfacial residual stresses that develop at the joints of CMCs and Ni-based superalloys, which can severely impair the performance of the hybrid components. The mechanisms behind the formation of residual stress in CMCs/Ni-based superalloys joints are reviewed, including thermal expansion coefficient (CTE) mismatch, thermal gradient difference, and phase transformation, and various methodologies for alleviating these stresses are summarized, including interlayer techniques, composite filler approaches, and interface structure design strategies. Finally, the challenges and future trends in mitigating interfacial stress in CMCs/Ni-based superalloys joints are discussed.

The composition−property relationship of 18 quaternary high entropy diborides (HEBs) consisting of boron and IVB, VB and VIB transition metals (TM) was investigated using first-principles calculations. A valence electron concentration−relative electronegativity (VEC−REN) composite descriptor was developed to effectively predict the mechanical properties of HEBs. The results demonstrate that with a fixed VEC, the rise of the REN makes HEBs harder but more brittle when the electronegativity of doped TM atoms is lower than that of boron atoms. However, HEBs become softer and more ductile as REN increases if the doped TM atoms have higher electronegativity than boron atoms. The VEC−REN composite descriptor can accurately classify and predict the mechanical properties of HEBs with different components, which provides important theoretical guidance for the rapid design and development of novel high-entropy ceramic materials.

Copper matrix composites prepared via traditional methods face mechanical property and electrical conductivity trade-off problems. In this study, TiB₂/Cu−Cu heterogeneous laminated composites with submicron lamellar thicknesses were prepared via flake powder metallurgy (FPM) using gas-atomized in situ composite powders as raw material. By thermal mismatch strengthening, and the geometrically necessary dislocations (GNDs) generated by mechanically incompatible deformation between adjacent heterogeneous lamellae and their interaction with statistically stored dislocations (SSDs), the as-prepared TiB₂/Cu−Cu submicron laminated composites (SLCs) exhibit significantly enhanced mechanical properties. At the same time, the interaction and propagation of multimode cracks provide extrinsic toughening for SLCs. The pure Cu lamellae with low density grain boundaries and dislocations and no TiB₂ particles provide a channel with little electron scattering for the rapid transport of carriers, thereby ensuring high electrical conductivity.

The molten CaCl₂−CaMoO₄ system was investigated, and the electrodeposition of protective Mo coatings on Ni plates was demonstrated. The results confirm the high solubility of solid CaMoO₄ and the electrochemical reactivity of MoO₄^2– ions in molten CaCl₂. The eutectic temperature and composition of the system are identified as 1021 K and 4.74 wt.% CaMoO₄, respectively. Under constant-current electrolysis conditions of −10 mA/cm² at 1123 K, uniform and dense Mo coatings are obtained on Ni plates with up to 90.31% efficiency. Increasing the current density raises the overpotential, leading to refined grains and decreased roughness. The Mo-coated Ni plate exhibits a significant improvement in hardness and corrosion resistance. Microhardness increases from HV 46.00 to HV 215.10 after coating, and the corrosion rate in a 20 wt.% NaCl solution at room temperature decreases to 0.1% that of the bare plate. These findings enhance our understanding of the molten CaCl₂–CaMoO₄ system and emphasize the potential of innovative Mo coating technologies.

Some active metal oxides (Al₂O₃, TiO₂, and Cr₂O₃) were selected as dopants to the Al₂O₃-based ceramic shells for investment casting of K417G superalloy. The effects of dopant types and contents (0, 2, 5, and 8 wt.%) on the wettability and interfacial reaction between the alloy and shell were investigated by a sessile-drop experiment. The results show that increasing the Al₂O₃ doping contents (0−8 wt.%) reduces the porosity (21.74%−10.08%) and roughness (3.22−1.34 μm) of the shell surface. The increase in Cr₂O₃ dopant content (2−8 wt.%) further exacerbates the interfacial reaction, leading to an increase in the thickness of the reaction layer (2.6−3.1 μm) and a decrease in the wetting angle (93.9°−91.0°). The addition of Al₂O₃ and TiO₂ dopants leads to the formation of Al₂TiO₅ composite oxides in the reaction products, which effectively inhibits the interfacial reaction. The increase in TiO₂ dopant contents (0−8 wt.%) further promotes the formation of Al₂TiO₅, which decreases the thickness of the interfacial reaction layer (3.9−1.2 μm) and increases the wetting angle (95.0°−103.8°). The introduced dopants enhance the packing density of the shell surface, while simultaneously suppress the diffusion of active metal elements from the alloy matrix to the interface.

The effects of artificial aging (T6) on the creep resistance with tensile stresses in the range of 50−80 MPa at 175 °C were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn (wt.%) alloy. The Guinier-Preston (G.P.) zones primarily precipitate in the sample aged at 200 °C for 1 h (T6-200°C/1h), while the Al₂Ca phases mainly precipitate in the sample aged at 275 °C for 8 h (T6-275°C/8h). The T6-200°C/1h sample exhibits excellent creep resistance, with a steady-state creep rate one order of magnitude lower than that of the T6-275°C/8h sample. The abnormally high stress exponent (~8.2) observed in the T6-200°C/1h sample is associated with the power-law breakdown mechanism. TEM analysis illuminates that the creep mechanism for the T6-200°C/1h sample is cross-slip between basal and prismatic dislocations, while the T6-275°C/8h sample exhibits a mixed mechanism of dislocation cross-slip and climb. Compared with the Al₂Ca phase, the dense G.P. zones effectively impede dislocation climb and glide during the creep process, demonstrating superior creep resistance of the T6-200°C/1h sample.

The flotation separation of cassiterite and dravite was realized using lead complexes of benzohydroxamic acid (Pb-BHA) as a collector and sodium fluosilicate (SF) as a depressant. Zeta potential tests confirmed that SF enabled the selective depression of dravite. The results of Fourier transform infrared (FTIR) spectroscopy analysis demonstrated that hydroxyl-containing groups in the hydrolysis products of SF selectively chemisorbed on the surface of dravite. X-ray photoelectron spectroscopy (XPS) analysis results further demonstrated the strong chemisorption of SF hydrolysis products (F-containing groups and hydroxyl-containing groups) on dravite (Mg sites). Consequently, the adsorption of Pb-BHA on dravite was selectively prevented. Based on the results, a selective depression model of SF on cassiterite and dravite was proposed.

The competition for future resources lies in the deep sea and the key to the development of deep-sea resources depends on the level of deep-sea equipment. To manufacture the equipment served in the deep sea, the key issue is to prepare the metal materials with required properties. High-entropy alloys are gaining increasing attention due to their excellent corrosion resistance in harsh environments, such as the deep sea. It is crucial to reveal the corrosion mechanisms of high-entropy alloys to develop alloys with excellent corrosion resistance and expand the applications of high-entropy alloys. In this review, the corrosion mechanisms and evaluation methods of high-entropy alloys are comprehensively reviewed based on the galvanic corrosion theory, point defect theory, and passivation theory. In addition, the strategies, including alloying and heat treatment, to improve the corrosion resistance of high-entropy alloys are summarized. The aim is to better understand the corrosion behavior of high-entropy alloys and provide theoretical guidance for developing high-entropy alloys with excellent corrosion resistance.

The flotation separation of argentite from sphalerite using ammonium dibutyl dithiophosphate (ADD) was studied. Molecular simulation (MS) calculation shows that ADD is chemisorbed on argentite and sphalerite surface in the form of S—P bond. The ADD adsorption on argentite and sphalerite surface in Ag⁺ system was revealed by ICP, Zeta potential and XPS analyses. It is shown that the dissolved Ag⁺ from argentite surface can be absorbed on sphalerite surface in the form of silver hydroxide, and AgOH hydrophilic colloid prevents the adsorption of ADD on sphalerite surface. The ADD adsorption on argentite and sphalerite surface in the pulp containing silver and zinc ions was revealed by adsorption capacity and surface wettability analyses. It is shown that the combined Zn(OH)₂ and AgOH hydrophilic colloid leads to greater ADD adsorption capacity on argentite surface and stronger surface hydrophobicity than sphalerite. Flotation tests demonstrate that ADD enables efficient separation of argentite from sphalerite in the pulp containing silver and zinc ions.

The effect of temperature on molten zone length was investigated through simulation to optimize the control of molten zone length during the experimental process. The temperature gradient distribution within the molten zone during zone refining was simulated using COMSOL Multiphysics software and experimentally validated. The simulated molten zone length showed good agreement with the actual measured length. The experimental study of tellurium purification by zone refining was conducted under the following conditions: three passes of zone refining, a hydrogen flow rate of 0.5 L/min, and molten zone movement speeds of 0.5 and 1.0 mm/min. The results demonstrated that the removal efficiencies of impurities such as Ca and Cu exceeded 95%, while the removal efficiency of phosphorus (P) reached over 70%. And the purity of tellurium reached 6N.

The differences in the competitive reactions of hydrogarnet and quicklime when reacting with titanium- containing and silicon-containing minerals during the Bayer digestion process were investigated. Thermodynamic analysis, artificial mineral experiments, and an evaluation of the digestion effect of natural diasporic bauxite were conducted. The results indicate that hydrogarnet shows a preferential reaction with anatase, and this preference becomes more pronounced as the silicon saturation coefficient increases. In contrast, quicklime participates in non-selective reactions with both anatase and desilication products (DSP). The preference of hydrogarnet for anatase significantly enhances the utilization efficiency of CaO in the high-temperature Bayer digestion process.

A clean and efficient process for the direct extraction of valuable metals from low-grade nickel sulfide ore through oxidative leaching with (NH₄)₂S₂O₈ under atmosphere pressure was proposed to address the growing demand for nickel and cobalt in the new energy industry. The effects of four key parameters on the metal leaching rates were systematically investigated. Characterization techniques, including XRD, SEM and EDS, were employed to analyze phase transformations during the leaching process. Under optimized conditions, approximately 96.5% of nickel, 95.5% of cobalt and 65.2% of copper were successfully extracted. The kinetics of the leaching process was explored to identify the controlling mechanisms of nickel, cobalt and copper dissolution, establishing activation energies and kinetic equations for each metal. The cleanliness and efficiency of this method were confirmed through comparisons with other extraction processes for nickel sulfide ore.

A collaborative optimization method for the sintering schedule of ternary cathode materials was proposed under microscopic coupling constraints. An oxygen vacancy concentration prediction model based on microscopic thermodynamics and a growth kinetics model based on neural networks were established. Then, optimization formulations were constructed in three stages to obtain an optimal sintering schedule that minimized energy consumption for different requirements. Simulations demonstrate that the models accurately predict the oxygen vacancy concentrations and grain size, with root mean square errors of approximately 5% and 3%, respectively. Furthermore, the optimized sintering schedule not only meets the required quality standards but also reduces sintering time by 12.31% and keeping temperature by 11.96%. This research provides new insights and methods for the preparation of ternary cathode materials.

The influence of thickness and annealing treatment on microstructure and soft magnetic properties of Fe−Si−B−Cu−Nb alloy (Finemet) thin films prepared by magnetron sputtering was systematically studied. As the thickness of the film increases, the coercivity decreases while the saturation magnetization increases, and then both reach a stable state. Following annealing at 773 and 873 K, nanocrystalline α-Fe precipitates within the thin film. The exchange coupling effect between nanocrystals and the amorphous matrix significantly enhances the soft magnetic properties of the thin film. Rapid-thermal process controls the heating rate to minimize grain size and optimize nanocrystal distribution, achieving lower coercivity and higher saturation magnetization without necessitating extra transition metals. Consequently, the Fe−Si−B−Nb−Cu thin film subjected to rapid-thermal process at 873 K for 30 min with a heating rate of 25 K/s exhibits low coercivity of 0.8 A/m and high saturation magnetization of 1.45 T.

A coupled three-dimensional cellular automata (CA) model has been used to predict the hydrogen porosity in an Al−Si alloy as a function of thermal boundary conditions. By quantifying the porosity distribution from simulations, a porosity defect database was established, representing a cooling rate ranging from 0.25 to 50 °C/s at an initial hydrogen content of 3.0×10⁻³ mL/g. Based on the database, four machine learning algorithms including support vector machine (SVM), random forest (RF), K-nearest neighbors (KNN), and gradient boosting machine (GBM) were trained and compared for each porosity characteristic to identify the optimal model. For the prediction of porosity percentage, the determination coefficient (R²) and the root mean square error (RMSE) on the test set reached 0.95 and 0.042, respectively. The predicted porosity distribution agreed well with experiments, indicating that the model can be used to map the porosity size in large casting components.

An initialization-improved equilibrium constant method was used for modelling the copper matte smelting process with flash technology. Initial molar amounts of species were calculated by distributing the amounts of given elements. The species containing the largest amount of one element was chosen to be the corresponding thermodynamic component. The equilibrium values were derived via the Newton−Raphson method and converted to industrial forecast values using the mechanical entrainment equations. The results indicate that the calculated equilibrium value for copper concentration in the slag is 0.32 wt.%, while the industrial forecast value is 1.03 wt.%, with the industrial value being 1.13 wt.%. The present model required only 31 outer loops to derive the approximate solution close to the equilibrium value. The iterative path during the computation is considerably reduced and the risk of non-convergence during the computation is decreased.

The leaching mechanism of gallium (Ga) and germanium (Ge) from zinc powder replacement residue (ZPRR) was investigated through ultrasonic-assisted sulfuric acid leaching. Characterization via XRD, SEM, XPS, and FT-IR revealed that ultrasonic treatment promotes the dehydration of H₄SiO₄ colloids, thereby reducing their adsorption capacities for Ga and Ge complexes. Additionally, ultrasound enhances the dissolution of CaS in H₂SO₄, increasing H₂S production, which aids in the reduction of Fe³⁺ and mitigates iron precipitate formation. Process parameters including ultrasonic power (0−450 W), temperature (100−120 °C), and leaching time (30−120 min) were systematically optimized, achieving optimal leaching efficiencies of Ga and Ge at 95.7% and 94.5%, respectively.

The leaching process and kinetic behavior of lepidolite in hydrochloric acid were explored systematically. The influence of leaching conditions on the leaching efficiency of valuable metals in lepidolite was investigated. Under optimized conditions, the leaching efficiencies of Li, K, Rb, Cs and Al are 92.02%, 93.31%, 88.59%, 86.75% and 81.07%, respectively. Kinetics research results show that the leaching process conforms to the shrinking core model that is under the mixed control of chemical reaction and diffusion through the solid product layer. In addition, the contribution of solid product layer diffusion to the leaching gradually expands as the temperature rises, but it is still significantly less than the contribution of chemical reaction. Cost saving in the neutralizing agent and leaching processes makes hydrochloric acid an economical leaching agent for lepidolite. Finally, the Li₂CO₃ product with a purity of 99.89% was synthesized from the hydrochloric acid leachate.

The effects of siderite, hematite, and goethite on pyrite reactions in sodium aluminate solution at high temperatures, based on the coexistence of pyrite and iron-bearing minerals in bauxite, were studied. The addition of siderite, goethite, and hematite increases the concentrations of S₂O₃²⁻, SO₃²⁻ and SO₄²⁻, enhancing sulfur removal during desilication. Siderite and hematite facilitate nearly 100% magnetite formation from pyrite, whereas goethite leads to the formation of both hematite and magnetite from pyrite through a multiphase transformation process. Iron-bearing minerals significantly increase the iron content in residues and enhance iron recovery from the red mud. Siderite, goethite, and hematite produce a porous surface in the form of erosive holes due to electrochemical corrosion, improving reaction efficiency of pyrite. Additionally, electrochemical corrosion promotes the pyrite reaction in accordance with the Kröger and Ziegler models, controlled by interfacial diffusion and chemical reactions in the presence of siderite, hematite and magnetite.

To achieve large-scale application of solvothermal method and settle structural collapse of polycrystalline ternary NCM cathode materials (LiNi_0.8Co_0.1Mn_0.1O₂, NCM811) during long charge and discharge cycling, single-crystalline NCM materials with high cycling stability were prepared by rapid ethanol−water solvothermal method. The morphology and electrochemical properties of NCM materials were characterized by X-ray diffractometry, cross-section scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical measurement. The results show that single-crystalline NCM synthesized with 60 min solvothermal time has the most excellent electrochemical performance. Its reversible capacity reaches 157.28 mA·h/g at 1C and retention rate achieves 55.06% after 200 cycles, which is much better than the polycrystalline NCM cathode material. Cross-section scanning electron microscopy results show that the single-crystalline NCM cathode material has no apparent cracks after 200 cycles.

A combination of rare earth (RE) alloying and plastic deformation was employed to improve the comprehensive properties of Mg−3Al−1Sn−0.5Ca−0.2Mn (ATXM) alloys. The results show that the rolled ATXM-0.1RE alloys exhibit remarkable simultaneous improvements in both mechanical strength and corrosion resistance. Specifically, the alloys with Sm, Ce, and Y additions demonstrate yield strengths of 238, 232, and 238 MPa, elongations of 18%, 17%, and 23%, and corrosion rates of approximately 3.4, 2.9, and 1.7 mm/a, respectively. Notably, the rolled ATXM-0.1Y alloy displays the optimal overall properties. The underlying mechanisms involve grain refinement (from ~50 μm to below 5 μm) and alterations in composition, dimension, and arrangement of secondary phases, which contribute to fine-grain strengthening and Orowan strengthening, thereby bolstering mechanical properties. Furthermore, these modifications mitigate the galvanic corrosion and strengthen the protective corrosion product film, resulting in a significantly improved corrosion resistance.

The melting and separation behavior of vanadium−titanium magnetite pellets directed at an efficient extraction of vanadium and titanium was systematically investigated. Applying FactSage simulations and experiments, the smelting separation of three pre-reduced pellets from different regions was analyzed. The simulations demonstrate that FeTi₂O₅ is converted to TiC at low temperatures, necessitating suppression of this step. Experiments under optimized conditions (1590−1690 °C, 20−25 min, 2% coke, basicity 0.4−0.6, and 3.0%−6.0% MgO) yield iron grade of 92.35%− 95.06%, titanium grade of 34.37%−39.89%, and vanadium grade of 0.56%−1.52%, with recoveries of 99.52%−99.60%, 94.08%−98.96%, and 92.63%−94.38% for iron, titanium and vanadium, respectively. The titanium in the slag, primarily in the form of anosovite, is suitable for sulfuric acid-based titanium white production. An increase in basicity, MgO content, and pellet metallization serves to improve vanadium recovery in melted iron but lowers the titanium grade in the slag. The overall process effectively utilizes vanadium and titanium resources under optimized conditions.

The dissimilar 2B06 and 7B04 Al alloy joints were prepared by refill friction stir spot welding (RFSSW), and the microstructural evolution and corrosion behavior of the joints were investigated. Based on microstructural analysis, the welded joints exhibit distinct microstructural zones, including the stir zone (SZ), thermomechanically affected zone (TMAZ), and heat-affected zone (HAZ). The grain size of each zone is in the order of HAZ > TMAZ > SZ. Notably, the TMAZ and HAZ contain significantly larger secondary-phase particles compared to the SZ, with particle size in the HAZ increasing at higher rotational speeds. Electrochemical tests indicate that corrosion susceptibility follows the sequence of HAZ > TMAZ > SZ > BM, with greater sensitivity observed at increased rotational speeds. Post-corrosion mechanical performance degradation primarily arises from crevice corrosion at joint overlaps, but not from the changes in the microstructure.

The volatilization characteristics and kinetic mechanisms of arsenic were investigated in the temperature range of 623−773 K and pressure ranges of 10−10000 Pa. The experimental results reveal that the evaporation rate increases with increasing temperature and decreasing pressure. Surface reaction control dominates at low pressures (<100 Pa), whereas diffusion control dominates at high pressures (>5000 Pa). The evaporation behavior is successfully described by an Arrhenius-type model for temperature dependence and Logistic model for pressure dependence. Key kinetic parameters, including the critical pressure, maximum evaporation rate and evaporation coefficient, were calculated. The evaporation coefficient varies between 0.010 and 0.223, and the critical pressures vary between 281 and 478 Pa with temperature.

Nanocrystalline Zn−3Cu−0.2Sr−xLi (x=0, 0.2, 0.4, wt.%) alloys were prepared via high-speed rolling to meet the urgent demand for high-performance alloys in the biomedical field. The high-speed rolling process generated numerous dislocations, providing sufficient driving force for recrystallization. The addition of Li promoted the formation of ε and β phases. These secondary phases provided abundant heterogeneous nucleation sites and a strong pinning effect, facilitating recrystallized grain nucleation while inhibiting its growth. The grain size of the alloy containing 0.4 wt.% Li was refined from 181.8 μm to 50 nm after rolling. The ultimate tensile strength, yield strength, and elongation of the rolled alloy containing 0.4 wt.% Li achieved 433.3 MPa, 389.2 MPa, and 15.2%, respectively. Compared to the as-cast Li-free alloy, 0.4Li alloy demonstrated a 173% increase in yield strength and a 591% improvement in elongation. Nanocrystalline strengthening was the dominant mechanism, contributing 70.4% to the total yield strength of the rolled Zn−3Cu−0.2Sr−0.4Li alloy.

The suspension stage of copper flash smelting was examined by roasting a high arsenic copper smelting feed mixture at 500−900 °C for 0−20 s in nitrogen and air atmospheres. The enrichment of copper, lead, zinc, arsenic, and sulfur in the quenched calcine was determined via chemical analyses. Pyrite and chalcopyrite were the main minerals in the feed mixture, and about 55 wt.% of arsenic was in tennantite. The stability of the feed and the formation of S₂ and SO₂ during roasting were surveyed by thermal analysis combined with mass spectrometry. Selected pure impurity sulfides were studied for reference purposes. Results indicated that arsenic was released more easily in inert atmosphere compared to air, in which oxidation products of sulfides captured the released gaseous arsenic. Kinetics analyses showed that the third-order chemical reaction and three-dimensional diffusion models were found as the most suitable mechanism functions of arsenic volatilization in inert and air atmospheres, respectively.

Mg−6Zn−0.6Zr alloys with varying Ca contents (0, 0.6, 1.2, 1.8 wt.%) were prepared by gravity casting and hot extrusion. The effect of Ca content on the microstructure, mechanical properties, and ignition resistance of Mg−6Zn−0.6Zr alloy was investigated. The results show that Ca addition promotes Ca₂Mg₆Zn₃ phase formation while inhibiting MgZn₂ precipitation in as-cast alloys. After homogenization, the MgZn₂ phases are nearly dissolved, while numerous Ca₂Mg₆Zn₃ phases remain. During extrusion, the Ca₂Mg₆Zn₃ phases fragment, and MgZn₂ nanoparticles precipitate in the matrix. The combination of fine grains and high-density precipitates significantly enhances the strength of the Ca-containing alloys. The Mg−6Zn−0.6Zr−1.2Ca alloy exhibits the best overall mechanical properties, with ultimate tensile strength of 380.1 MPa, yield strength of 360.1 MPa, and elongation of 10.4%. Additionally, the ignition point increases from 556 to 824 °C with rising Ca content due to the formation of a dense CaO−MgO oxide layer.

The effects and underlying mechanisms of aging treatment on the microstructure and properties of Cu−0.3Be−2.0Ni and Cu−0.3Be−2.0Ni−0.2Al alloys (subjected to solid solution treatment followed by 70% cold rolling) were investigated. Results showed that the Cu−0.3Be−2.0Ni alloy mainly precipitated the Ni−Be phase, while the Cu−0.3Be−2.0Ni−0.2Al alloy exhibited co-precipitation of both Ni−Be and Ni₃Al phases. The combined strengthening from nanoscale Ni₃Al and Be−Ni phases significantly increased the strength of the Cu−0.3Be−2.0Ni−0.2Al alloy compared to the Cu−0.3Be−2.0Ni alloy. Thermo-mechanical treatment improved both the hardness and electrical conductivity of the alloys. Compared with conventional aging, the Cu−0.3Be−2.0Ni−0.2Al alloy showed a 13% increase in hardness and a 6.8% increase in electrical conductivity, while the Cu−0.3Be−2.0Ni alloy exhibited a 6% hardness increase with slight conductivity improvement.

The flow characteristics and deformation mechanism of Al−Mg−Si alloy were studied at various temperatures (77−298 K) and strain rates (900−7000 s⁻¹) using the Hopkinson pressure bar method, electron backscattered diffraction (EBSD), and transmission electron microscopy (TEM). The results showed that increasing the strain rate and decreasing the deformation temperature significantly enhanced the work hardening ability of Al−Mg−Si alloy, thereby markedly improving the plasticity. A dislocation density-based constitutive model for the Al−Mg−Si alloy was established, incorporating dislocation accumulation and dynamic recovery mechanisms, which accurately described the flow behaviors under different conditions. Microstructural observation revealed that the combination of cryogenic temperature and high strain rate significantly suppressed dislocation cross-slip, which led to the formation of numerous slip bands. As strain accumulated, these slip bands interacted and facilitated recrystallization, thereby obviously accelerating the grain refinement process.

The recovery of metallic values from spent cathode active powders in lithium-ion battery was investigated in a deep eutectic solvent (DES) based on choline chloride (ChCl) and ethylene glycol (EG). The recovery yields of Li, Co, Mn and Ni metals were 97.2%, 99.2%, 97.6% and 100%, respectively, in the leaching process carried out at 180 °C, under 375 r/min magnetic stirring speed and at 10 g/L pulp density for 24 h using CC꞉EG 1꞉2 as solvent. Leaching yields very close to these results were also obtained after 12 h leaching using 200 W ultrasonic support (US) instead of magnetic stirring under the same conditions. 2 mol/L Na₂CO₃ was used for co-precipitation of metals from metal loaded solutions. The precipitation efficiencies for Li, Co, Mn and Ni after co-precipitation at pH (11.6±0.05), 40 °C for 3 h are 85.7%, 95.8%, 99.8% and 89.9%, respectively. Furthermore, multiple utilization of DES was investigated, and three cycles were completed without loss of yield in both extraction and stripping stages. The precipitation product was calcined and characterized by XRD and SEM techniques.

The Furong pluton, located in central Hunan, China, hosts numerous tungsten veins within and around the granite, which are of great economic significance. However, its petrogenesis and related mineralization are poorly constrained. In this study, we used U−Pb dating, petrological and geochemical methods to ascertain the emplacement time, classification of granitic rock, nature of the source rocks, formation mechanism, and its geodynamic implications for the Furong pluton. It is shown that the granite is precisely determined to be formed at ~210 Ma, and belongs to the moderately-fractionated S-type granite. Combined with regional tectonic setting, it is concluded that the pluton was formed due to crust extension and thinning followed by plate collision and compression in South China. It is also revealed that tungsten mineralization and Indosinian granites exhibit a close temporal, spatial and genetic relationships, and further exploration of tungsten deposits within and around the granite in central Hunan, even in South China, is urgently needed.

The effects of combined microwave and hydrogen peroxide (H₂O₂) oxidation on the flotation separation of molybdenite and chalcopyrite, as well as the underlying mechanism were investigated via microflotation, zeta potential, contact angle, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses. The microflotation experiments showed that the effective inhibition of chalcopyrite can be obtained through combined oxidation pretreatments with low microwave power and H₂O₂ consumption. The zeta potential, contact angle and XPS analyses indicated that the surface hydrophobicity of molybdenite changed minimally after different treatments, whereas significant amounts of hydrophilic oxidation species were formed on the surface of chalcopyrite, thus decreasing its surface hydrophobicity and floatability. Moreover, the SEM and AFM analyses indicated that more uniform oxidative products were formed on the chalcopyrite surface, further significantly increasing the surface roughness.

The hydrogen reduction kinetics of tungsten trioxide (WO₃) was investigated via non-isothermal thermogravimetric analysis. Under the local gas–solid reduction conditions, the particle morphology of tungsten powders was found to be consistent with that of raw material WO₃. The removal of oxygen from tungsten oxide during hydrogen reduction led to the formation of porous structures between the reduced particles, which were obviously different from the polyhedral single-crystal configuration of tungsten powders obtained via chemical vapor deposition. Moreover, the two-stage hydrogen reduction mechanisms of WO₃ under the local gas–solid reduction conditions can be described using the composite autocatalytic function. The activation energies of the first and second stages of the hydrogen reduction of WO₃ were determined to be 121 and 135 kJ/mol, respectively.

The microstructural evolution of Cu−19Ni−6Cr−7Mn alloy during aging treatment was investigated. After aging for 120 min at 500 °C, the alloy exhibited excellent mechanical properties, including a tensile strength of 978 MPa and an elastic modulus of 145.8 GPa. After aging for 240 min at 500 °C, the elastic modulus of the alloy reached 149.5 GPa, which was among the highest values reported for Cu alloys. It was worth mentioning that the tensile strength increased rapidly from 740 to 934 MPa after aging for 5 min at 500 °C, which was close to the maximum tensile strength (978 MPa). Analysis of the underlying strengthening mechanisms and phase transformation behavior revealed that the Cu−19Ni−6Cr−7Mn alloy underwent spinodal decomposition and DO₂₂ ordering during the first 5 min of aging at 500 °C, and L1₂ ordered phases and bcc-Cr precipitates appeared. Therefore, the enhanced mechanical properties of the Cu−19Ni−6Cr−7Mn alloy can be attributed to the stress field generated by spinodal decomposition and the presence of nanoscale ordered phase and Cr precipitates.

Eco-friendly thiosulfate is a promising alternative to the high-toxic cyanide for gold extraction with copper− ammonia catalytic system being the most popular. However, the copper−ammonia catalysis causes the issues of high thiosulfate consumption, complex gold recovery process and ammonia pollution. An effective strategy to tackle these issues is to improve or replace the copper−ammonia system with a novel catalytic system (NCS). Various NCSs are classified and their current status and future prospectives are reviewed. The critical constituent factors of NCSs are summarized. The noteworthy developing trends of potential NCSs are also discussed. Furthermore, besides resin adsorption, other recovery methods such as solvent extraction deserve more attention to achieve selective gold recovery. Crucial insights into developing suitable NCSs to solve the existing challenges in the current thiosulfate leaching technology once and for all are offered, thus promoting its large-scale industrial application.

A CFD-based numerical model was employed to quantitatively analyze the flow characteristics of double-side-blown gas−liquid flow. Key parameters were extracted, and Spearman correlation analysis was used to quantify the relationships among bubble behavior, circulating flow, and liquid oscillations. The results show that periodic bubble behavior under steady injection drives the circulating flow of the liquid on both sides. The asynchronism of bubble behavior on both sides results in the alternation of circulating intensity, which significantly enhances gas−liquid mixing efficiency at certain liquid levels of 200 and 220 mm. Flow patterns of the double-side-blown process are classified into weak circulation, strong−weak alternating circulation, and strong circulation modes based on the influence of circulating flows on the penetration depth. The penetration depth in the strong−weak alternating circulation mode is generally greater than that in the single-side-blown process. The imbalance of circulating intensities on both sides primarily leads to the stable fluctuation in the injecting direction, which reveals the appearance of periodic oscillations in the molten bath. The effect of control parameters such as liquid level and gas flow rate on the liquid oscillations were discussed.