Compared with the traditional CO2-Enhanced Coalbed Methane Recovery (CO2-ECBM) technology, hot flue gas enhanced deep coalbed methane (CBM) recovery not only improves gas production rates but also effectively reduces the costs associated with carbon capture, which holds significant implications for large-scale carbon emission reduction. However, the microscopic mechanism of competitive adsorption of multicomponent gases under the constraint of semi-closed pores in deep hard-to-extract coal seams remains unclear. Daliuta bituminous coal was selected, and the coal molecular structure was determined combining elemental analysis, 13C nuclear magnetic resonance (13C NMR), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Meanwhile, the coal pore structure was characterized via N2/CO2 adsorption. Based on these characterizations, a single-pore unit model compacted from real coal macromolecules(neck diameter 4 nm, cavity diameter 10 nm)was constructed. Subsequently, molecular simulations of in-situ methane adsorption and diffusion, as well as competitive adsorption of multicomponent in hot flue gas, were performed. The findings reveal that within the temperature range of 303.15–423.15 K, the CH4 isothermal adsorption isotherm of ink-bottle pores exhibits an inflection point of neck saturated adsorption at 0.18 mmol/g. When the coal seam depth increases from 500 m to 2000 m, the CH4 diffusion coefficient decreases from 4.29 × 10-8 m2/s to 4.05 × 10-8 m2/s, and methane migration is restricted under high pressure and high load conditions. The interaction energies between coal molecule and SO2, NO2, H2O(g), CO2, CH4, and N2 are −13.26, −9.89, −8.47, −8.23, −3.74, and −3.33 kcal/mol respectively. Among these, the strongly adsorbing gases exhibit interaction energies that are 2.2 to 3.5 times those of CH4. Based on the comprehensive analysis of binary and multicomponent simulation results, the competitive adsorption relationship between flue gas components and methane in ink-bottle pore unit is determined as NO2 > SO2 > H2O(g)> CO2 > CH4 > N2. At low pressures (0–3 MPa), CO2 adsorption dominates; at high pressures (3–5 MPa), N2 takes over from CO2 and becomes the primary gas that inhibits CH4 adsorption. The present study can provide theoretical guidance for coalbed methane (CBM) extraction in deep coal seams with semi-closed pores.

The increasing prevalence of antibiotic resistance has necessitated the development of novel antimicrobial strategies. Tin disulfide (SnS2), a semiconductor nanomaterial with unique physicochemical properties, has emerged as a promising candidate for combating bacterial infections. In this study, we synthesized SnS2 nanoflowers with narrow band gaps using the hydrothermal method and developed Cu@SnS2 nanoflowers through the doping of copper ions. The Cu@SnS2 nanoflowers exhibited excellent catalytic performance. Under ultrasound (US) radiation, they can generate a substantial amount of reactive oxygen species (ROS) and demonstrate a high inhibition rate against E. coli and S. aureus. The antibacterial mechanism is attributed to the generation of ROS, and the disruption of bacterial cell membranes. Additionally, cytotoxicity assays revealed low toxicity toward mammalian cells, indicating the potential of Cu@SnS2 nanoflowers as safe and effective antimicrobial agents. In vivo experiments further indicated that Cu@SnS2 nanoflowers could effectively expedite the healing of bacterially infected wounds. The wound healing rate reached 91.7 % within nine days. Consequently, as a novel acoustic catalytic material, SnS2 present a viable strategy to surmount the limitations of conventional treatments for bacterial wound infections.

Barite, as an irreplaceable strategic mineral resource, possesses a wide array of industrial applications. Carbonate-type barite is a typical representative among barite deposits. However, the traditional industrial collector sodium oleate (NaOL) exhibits insufficient collection capacity for barite. To address above issue, this work selected the novel sodium N-lauroylsarcosine (NaNL) as an efficient collector for barite in acidified sodium silicate (ASS) system. Flotation tests of real ore indicated that when 300 g/t NaOL was used as the collector, the grade and recovery of BaSO4 in the flotation concentrate were 94.56% and 18.14%, respectively. In contrast, when NaNL (100 g/t) was utilized as the collector, the grade and recovery of BaSO4 in the flotation concentrate could reach 94.07% and 58.06%, respectively. NaNL exhibited superior collecting ability for barite compared to NaOL in the ASS system. The adsorption density measurements demonstrated that the adsorption of ASS onto the calcite surface could significantly prevent the further adsorption of NaNL onto the calcite surface, resulting in greater adsorption of NaNL on barite than on calcite. Density functional theory (DFT) calculations revealed that, NaNL could relatively easily replace the ASS adsorbed on barite, and difficultly replace ASS adsorbed on calcite, thereby achieving selective separation of barite from calcite. Hence, low-dosage NaNL possesses significant potential for industrial application in barite flotation

The Discrete Element Method (DEM) is widely applied to analyze the mechanical behavior and breakage characteristics of ores and rock-like materials. The accuracy of DEM simulations, however, depends critically on the proper calibration of model parameters. In this study, a systematic calibration framework for copper ore was developed by combining laboratory testing, numerical simulations, and a response surface methodology based on the angle of repose (AoR). The calibrated parameter set includes both the fundamental physical properties required for the DEM contact model and the key parameters used in constructing Bonded-Particle Models (BPM) and Particle Replacement Models (PRM). Validation through uniaxial compression and single-particle impact tests confirms that the calibrated parameters accurately captured the material’s strength and fragmentation behavior. The results indicated that the proposed calibration approach yields consistent parameters and is suitable for modeling copper ore comminution. This framework provides a practical reference for subsequent research and engineering applications in mineral processing.

Rising global production of electrolytic aluminum has increased the need for safe management of waste barrier material. The proper disposal and resource utilization of waste barrier material from aluminum electrolysis cells has become a pressing issue. Nitric acid leaching was applied to recover lithium, aluminum, and sodium from waste barrier material originating from aluminum electrolysis cells. The effects of nitric acid concentration, liquid-to-solid ratio, reaction temperature, and duration on the leaching efficiency of these elements were systematically investigated. Microstructural and mineralogical changes during leaching were examined by scanning electron microscopy (SEM), X‑ray diffraction (XRD), Fourier‑transform infrared spectroscopy (FTIR), and particle‑size analysis. The results indicated that under optimal conditions of 90°C leaching temperature, 1.5 h reaction time, 0.9 M HNO3, and a liquid-to-solid ratio of 20:1, extraction rates of 96.6

Driven by the demand for greener and cost-effective solutions for lithium-ion battery recycling, direct regeneration of cathode materials from spent batteries has gained significant attention. To address the growing requirements for higher operating voltage and energy density in energy storage systems, LiMnxFe1-xPO4 (LMFP) has emerged as a promising cathode material for next-generation batteries due to its superior electrochemical performance compared to conventional LiFePO4 (LFP). Herein, we propose a novel upcycling strategy that transforms LFP into high-performance LMFP through a facile high-temperature solid-state synthesis method. The regenerated LMFP cathode exhibits reduced particle size, well-defined crystallinity, and exceptional electrochemical properties, delivering a specific capacity of 144.7 mAh g-1 at 0.5C, a rate capability of 120.5 mAh g-1 at 5.0C, and 91.1% capacity retention after 500 cycles at 1.0C. The underlying phase transformation and Mn activation mechanisms during high-temperature calcination were systematically investigated, revealing critical insights into the structural evolution from LFP to LMFP. This work provides fundamental insights into the design of efficient upcycling strategies for transitioning low-voltage cathodes to advanced high-energy-density materials, offering both environmental and technological benefits for sustainable energy storage.

This study aims to achieve the efficient and green extraction of isomorphically hosted vanadium from stone coal. To this end, a novel barite calcining-sulfuric acid leaching process was systematically investigated, and its intrinsic synergistic mechanism of activation-fixation-selective dissociation was elucidated. Through the optimization of calcining and leaching parameters, the optimal conditions were determined: calcining at 950 degrees C for 8 h with a 10 % barite dosage, followed by leaching with 2 % sulfuric acid at a liquid-to-solid ratio of 25 mL/g and 90 degrees C for 15 min. Under these conditions, a high vanadium leaching efficiency of 89.9 % (approaching 90 %) was achieved, accompanied by exceptionally fast leaching kinetics. Mechanistic investigations reveal that the calcining process hinges on the oxidation of inert V(III) to V(V) and its subsequent in-situ reaction with an active barium source derived from barite, leading to the targeted fixation into acid-soluble barium vanadate. During leaching, H+ and SO4 2- exhibit a synergistic effect: H+ dissolves the barium vanadate, releasing vanadium as VO2+ into the solution, while SO4 2- simultaneously precipitates Ba2+, regenerating barite within the residue. This coupled "acid dissolution-precipitation" mechanism not only provides a powerful thermodynamic driving force due to the extremely low solubility of BaSO4, ensuring a rapid and complete reaction but also enables the internal recycling of the barium agent and prevents the generation of additional solid waste at the source. This process simultaneously overcomes the trade-offs among efficiency, environmental impact, and cost-effectiveness inherent in conventional methods, offering a highly promising and clean alternative for vanadium extraction from stone coal.

Tailoring the as-cast microstructure of Ti-6Al-4V alloy into a refined, uniform structure through thermomechanical processing (TMP) is critical for optimizing its mechanical properties. Despite the well-established industrial effectiveness of sequential deformation from the single-phase β field to the dual-phase α + β field, the microstructural heredity between consecutive deformation passes remains poorly understood. This study investigates the microstructural evolution and inheritance of as-cast Ti-6Al-4V alloy subjected to hot deformation under different alternative phase field routes and strain rates. The results show that deformation across different phase fields promotes flow softening through the synergistic effects of β grains dynamic recrystallization (DRX) and lamellar α dynamic spheroidization (DS). At low strain rate (0.001 s−1), the inherited fine β grains and lamellar α from single-phase β field deformation accelerate lamellar α DS during subsequent dual-phase α + β field deformation. Concurrently, dual phase α + β field deformation enhances DRX of β grains by promoting the DS of GBα, ultimately leading to homogeneous DS of both grain boundary α (GBα) and intragranular lamellar α. At a high strain rate (0.1 s−1), GBα spheroidizes rapidly, while intragranular lamellar α evolves mainly through bending and fusion. This work provides a scientific basis for designing TMP routes to achieve controlled microstructures.

As a hazardous waste, tungsten slag contains residual critical strategic metals such as W and Mo, which hold significant recovery value. In this study, a roasting-water leaching method with composite additive has been developed to achieve the efficient recovery of W and Mo. Adding 5% NaCl, 5% Na2CO3, and 15% SiO2 to tungsten slag, followed by roasting at 850 ℃ for 1 h. Subsequently, the roasted product undergoes stirred water leaching for 15 min under the conditions of a liquid-to-solid (L/S) ratio of 2:1, a temperature of 25 ℃, and a stirring speed of 300 rpm. Ultimately, the recoveries of W and Mo reach 93.41% and 96.73%, respectively. Additionally, combined with reaction thermodynamic calculations, and characterization methods such as XRD and SEM-EDS, the reaction mechanism during the roasting-water leaching process was analyzed, and the mechanism of the soluble transformation of tungsten during roasting was discussed in detail. The results suggest that in the overall system, CaWO4 reacts with Na+, releasing Ca2+ and WO42-. Meanwhile, SiO2 effectively immobilizes Ca2+ to form more stable Ca2SiO4 or Ca4Si2O7F2. Molybdenite is oxidized at high temperature to form Na2MoO4, achieving the soluble phase transformation of tungsten and molybdenum minerals in the tungsten slag, which facilitates subsequent recovery by water leaching. This study offers new insights into the efficient recovery of W and Mo from tungsten slag.

The collective enrichment of scheelite, wolframite, and cassiterite remains a significant challenge. This study investigates the distinct flotation behaviors of these minerals under Pb-BHA (lead complex of benzohydroxamic acid) through single-mineral flotation experiments. Quantum chemical analysis provides initial insights into the difference in their flotation rates based on their crystal structures. An asynchronous flotation process was designed to replace the synchronous process. And a new collector, Pb-MBHA (lead complex of P-methylbenzohydroxamic acid), was developed to enhance mineral recovery. The new process leverages the differential flotation kinetics of the three W-Sn minerals through the transition from a single- to dual-process, and employs stage-tailored pH conditions and flotation reagents to produce distinct concentrates. The new process and collector, implemented in a 1500 t/d concentrator, significantly increased the recovery rates of tungsten and tin. The recovery rate of WO3 increased from 70 % to 78 %, while the recovery rate of Sn increased from 9 % to 22 %, generating an additional profit of $18,661.67/d. this research provides a very meaningful new approach to the comprehensive recovery of W-Sn minerals in complex W-Sn deposits

The effects of jet velocity, agitation speed, and air supplement flow rate on bubble size distribution were systematically investigated in a novel jet-mechanical agitation (JMA) flotation column. The results show that increasing jet velocity effectively reduces the maximum bubble size dmax from 4.74 mm to 4.24 mm while the Sauter mean diameter d32 remains around 2.00 mm, indicating a limited effect on the overall bubble size distribution. Shear-driven breakup and swirling-induced coalescence counterbalance each other under different agitation speeds, keeping d32 near 1.90 mm while the C value declines from 0.43 to 0.38, indicating reduced uniformity at excessive speeds. The air supplement flow rate exerts a stronger influence than jet velocity or agitation speed, raising d32 markedly from 0.44 mm to 2.61 mm while simultaneously increasing the proportions of both -0.10 mm and + 1.00 mm bubbles. An empirical d32 model (with coefficients k = 0.583, alpha = -0.30, beta = 0.019, eta = 3.22, gamma = 0.56) was developed, achieving a training error of 4.20% and a LOOCV error of 5.10%, confirming its reliability for predicting bubble size within the investigated range. This study quantifies the individual effects of operational parameters on bubble size, providing an experimental basis for the directional regulation of bubble size distribution and for subsequent flotation research in the JMA flotation column.

Efficient separation of galena (PbS) from pyrite (FeS2) remains a significant challenge in mineral processing. Traditionally, lime (CaO) has been used as a depressant to separate pyrite from galena in flotation processes. However, excessive lime use poses a serious threat to equipment, the environment, and worker safety. This paper proposes a method for separating pyrite from galena by surface modification of pyrite using green oxidant potassium ferrate (PF) under alkali-free conditions, followed by selective adsorption with dextrin. Single-mineral flotation tests show that using 40 mg/L PF and 20 mg/L dextrin yields an 80.5 % recovery difference between galena and pyrite. In mixed-mineral flotation tests, a lead concentrate with 71.82 % Pb grade and 88.07 % Pb recovery was obtained. PF's strong oxidation deactivates the xanthate pre-adsorbed on the pyrite surface. Additionally, combining PF with dextrin allows iron ions from PF to provide new sites on the pyrite surface, enhancing dextrin adsorption.

The strategic significance of fluorite as a critical source for the fluorine industry has received attention, and flotation separation is the most common technique for enriching fluorite. The efficient flotation separation remains challenging due to the ubiquitous coexistence of calcite and barite with similar surface physicochemical properties. The lack of intrinsically selective collectors severely limits fluorite recovery and separation efficiency. Herein, we report a novel ether-functionalized hydroxamic acid collector, benzyloxyacetyl hydroxamic acid (BOHA), rationally designed by introducing an ether linkage (C-O-C) into benzohydroxamic acid (BHA) to enhance selective interfacial interactions with fluorite. Flotation separation results revealed that BOHA maintained >90% fluorite recovery and exhibited a large flotation recovery gap (Delta R) of similar to 70% relative to calcite and barite at optimal conditions, demonstrating improved floatability and selectivity compared with the traditional collectors. Combined with the spectroscopic analysis and theoretical simulation, it was revealed that the high selectivity and adsorption strength of BOHA toward fluorite stems from a synergistic adsorption mechanism, in which the ether oxygen and hydroxamic acid group cooperatively coordinate with surface Ca2+ to form CaO bonds and a stable bidentate five-membered chelation structure. In addition, the strong cation-pi interactions between the benzene ring of BOHA and the fluorite surface further enhanced the adsorption strength of BOHA based on the DFT calculations. This work establishes a molecular-level design strategy for high-performance fluorite collectors by integrating specific chemical bonding and non-covalent interactions, which offers fundamental insights and practical guidance for the selective separation of fluorite and other calcium-bearing mineral systems.

Apatite is a key raw material for high-purity phosphoric acid production, yet its separation from siliceous (quartz and K-feldspar) and carbonate (dolomite) gangue in China’s phosphate ores remains challenging. To address this issue, a novel amino-acid-based collector, 3-(dodecylamino)butanoic acid (DABA), was synthesized and its separation mechanism in apatite flotation was systematically investigated. Flotation experiments show that at pH 6, DABA efficiently removes siliceous gangue by reverse flotation whereas at pH 10, the combined use of DABA and pectin depressant enables effective direct flotation of apatite. Mechanistic analysis reveals that DABA selectivity originates from pH-dependent adsorption. Under weakly alkaline conditions, anionic DABA forms strong chemical bonds with surface Ca2+ ions on apatite, while pectin selectively inhibits its adsorption on dolomite. Under weakly acidic conditions, cationic DABA preferentially adsorbs onto siliceous gangue via electrostatic interaction and chemical bonding with Si/Al species. These findings highlight DABA as a versatile collector suitable for multiple flotation schemes, offering a green and efficient approach to the beneficiation of complex phosphate ores.

Beryllium (Be) in industrial solid wastes is highly mobile and highly toxic, making its long-term stabilization challenging and remobilization under changing environmental conditions likely. Inspired by natural mineralization processes, this study proposes an artificial mineralization strategy for Be immobilization based on aluminate-induced structural reconstruction. The stabilization performances of sodium aluminate, dicalcium silicate, and sodium silicate toward Be2+ were systematically compared, with sodium aluminate exhibiting the highest removal efficiency and stabilization capacity. Multiscale characterizations (XRD, TEM, XPS, and EELS) reveal that sodium aluminate undergoes hydrolysis to form an amorphous aluminum oxyhydroxide precursor dominated by an Al-O-(OH) framework, followed by progressive structural evolution and local ordering during long-term curing. No directly detectable well-crystallized Be-bearing phases were observed under the current characterization conditions. Instead, Be species are more likely present in highly dispersed or framework-associated states within the evolving aluminum oxyhydroxide matrix. In practical Be-containing lithium slag systems, over 99% Be immobilization is achieved, with negligible Be release observed over 120 days of curing. Our work demonstrates the potential feasibility of mineralization-assisted stabilization for highly toxic metals through coupled structural evolution and framework-associated immobilization processes, providing a theoretical basis and technical support for the geochemical stabilization of Be in complex solid waste systems.

For a long time, it has been quite difficult to effectively carry out flotation separation of magnesite and calcite owing to the fact that their physicochemical properties are essentially very similar. However, the primary interfacial mechanisms causing this similar flotation behavior are unknown, impeding predictions of site distribution in the carbonate mineral-collector system. In this study, a multiscale surface complexation modeling (SCM) combining dissolution kinetic, adsorption isotherm, and spectral characterization data was developed. The results demonstrate that magnesite and calcite followed a three-zone dissolution pattern, which was jointly controlled by proton and surface complexation reactions. The release of Mg2+ and Ca2+ ions from the crystal lattice regulated the evolution of surface sites and surface wettability. According to the SCM, the surface densities, protonation constants and species distributions of the magnesite and calcite were very similar. The control of sodium oleate (NaOL) adsorption was via dissolved-ion bridging bidentate-binuclear coordination mechanism operating on -MeOL and -CO3MeOL sites. Calcite demonstrated a marginally higher intrinsic binding affinity than that of magnesite, however, its offset by multisite interactions led to similar adsorption capacities and floatability. XPS and SEM-EDS evidence confirmed the formation of multisite complexes, which were also predicted by the SCM. These findings offer molecular insights into the differing adsorption behavior of NaOL, which enhances our understanding of the reactivity at the flotation interface of carbonate minerals. They could also provide a theoretical basis for controlling and predicting the flotation behavior of carbonate minerals.

This paper investigated the performance of Cr-reducing microflora coupled with Fe-Mn modified composite for the removal of hexavalent chromium (Cr(VI)) under varying nutritional conditions. Two composites (Py1Rh1 and MaRh@Ch-500) were synthesized from Fe-Mn based minerals under specific conditions. In low-nutrient conditions, the Flora+Py1Rh1 and Flora+MaRh@Ch-500 showed low removal rates of only 18.63% and 17.70% at 144 h, respectively, whereas the Flora-only achieved a higher removal efficiency. In sharp contrast, in complete nutrient conditions, the Flora+Py1Rh1 exhibited a high removal rate of 93.94% at 48 h, whereas the Flor-a+MaRh@Ch-500 achieved an even higher removal efficiency of 94.19% within 24 h. At the 125th hour, 3 mL of 1000 mg/L Cr(VI) was added to the Flora+Py1Rh1 and Flora+MaRh@Ch-500 group, and Cr(VI) was almost completely removed within the next 19 h. The above results indicate that complete nutrient supplementation significantly accelerated microbial-mediated Cr(VI) reduction. SEM analysis revealed that under complete nutrient conditions, both the growth and reproduction of microorganisms are promoted. Microbial community analysis revealed that the Fe-Mn-based composite and complete nutrients significantly changed the dominant bacterial genus composition compared to the control group, with a notable enrichment of three specific genera: Paraclostridium, Comamonas, and Clostridium_sensu_stricto_13, which are presumed to play a crucial role in Cr(VI) removal. PICRUSt-based functional prediction revealed that key metabolic pathways, including amino acid metabolism, carbohydrate metabolism, and membrane transport functions. These results highlight the potential of Cr-reducing microflora coupled with Fe-Mn modified composite under nutrient-sufficient conditions as an efficient strategy for remediating Cr(VI) in contaminated wastewater.

Mineral flotation is essential for efficient resource utilization, with grinding as a key pretreatment affecting mineral surface structure and flotation performance. Hematite, a crucial iron ore in steel production and environmental remediation, shows complex surface responses to grinding. However, the link between grinding conditions and surface defect formation is not fully understood. This study integrates SEM, EDS, XRD, EPR, and DFT to examine the multiscale effects of grinding on hematite. Results show that grinding conditions affect particle aggregation, surface topography, and elemental composition. EPR analysis reveals increased Fe-vacancy concentrations, particularly under wet-type ball milling. DFT calculations show significant differences in surface energy and defect formation energy across different crystal planes, with the (012) plane having the lowest surface energy. The study also finds that the formation of Fe-vacancy defects on the (012), (104), and (110) planes is more difficult than that of oxygen vacancies. Additionally, electron accumulation and depletion occur around Fe atoms near oxygen vacancies. These findings clarify the relationship between grinding conditions and surface defects, offering insights for designing selective flotation reagents and optimizing pretreatment strategies.