A porous wollastonite ceramic with high porosity and low density has been successfully fabricated at low temperature with silicate tailings and electrolytic manganese slag (MS) as primary raw materials in this study. The influences of calcination temperature, SiC, and MS addition amounts on porosity, water adsorption, pore size distribution, bulk density, and bending strength were systematically studied. The results showed that 0.4 wt

The flotation recovery of malachite from complex polymetallic ores is often severely depressed by high concentrations of Mg2+ in recycled water; however, the underlying mechanism and effective mitigation strategy remain unclear. In this study, microflotation experiments combined with surface characterization and spectroscopic analyses were conducted to elucidate the inhibitory role of Mg2+ in malachite sulfidization flotation and to evaluate the performance of a mixed-collector system. The results showed that in the sodium hydrosulfide (NaHS)-potassium butyl xanthate/potassium amyl xanthate (PBX/PAX) system, increasing the Mg2+ concentration from 0 to 100 mmol/L decreased malachite recovery by 37.13%. In contrast, the addition of benzohydroxamic acid (BHA) to the PBX/PAX system markedly improved flotation recovery under high-Mg2+ conditions. Scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), zeta-potential, X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed that Mg2+ promoted the formation of a heterogeneous Mg(OH)2-Cu-S composite deposit layer on the malachite surface, which blocked active Cu sites and suppressed the formation of the Cu-S sulfidized film. Contact-angle and adsorption results further showed that the synergistic interaction between BHA and PBX/PAX accelerated and enhanced collector adsorption, leading to a more stable hydrophobic surface. Fourier transform infrared (FTIR) spectra indicated that xanthates chemisorbed on Cu-S sites through Cu-S-C bond formation, whereas BHA coordinated with surface Cu2+ via Cu-O/N chelation. Their cooperative adsorption resulted in the formation of a Cu-S/Cu-O/N composite interfacial layer, which effectively alleviated Mg2+-induced surface passivation. These findings demonstrated that the mixed-collector system restored the hydrophobicity and flotation performance of malachite in high-Mg2+ water through synergistic interfacial reconstruction.

The leverage of cGAS-STING pathway activation via either chemotherapy, photodynamic therapy (PDT), or pyroptosis for sufficient induction of tumor immunogenicity and antitumor immune responses represents a promising strategy of tumor immunotherapy for overcoming the immunosuppressive tumor microenvironment and provoking long-lasting systemic immune responses. However, the reported strategies for maximized cGAS-STING activation via synergy of these different treatment modalities, to our knowledge, have been generally suffered from several key limitations, including low loading capacity of active pharmaceutical ingredients (API), uncontrolled drug release kinetics, and potential excipient-related toxicity. We report herein a full-API-based nanoplatform, DIM@M constructed entirely from Food and Drug Administration (FDA)-approved doxorubicin (DOX) and indocyanine green (ICG), human essential manganese ions, and tumor-derived cell membranes, without the use of any organic solvents, to potentiate immunotherapy of triple-negative breast cancer (TNBC). Specifically, DIM@M enhances not only innate immune responses via the Mn2+/DOX-driven cGAS-STING activation but also adaptive immunity through ICG-endowed photoactivation of caspase-1/gasdermin D-dependent pyroptosis. This coordinated cGAS-STING activation leads to a synergistic immunologic circuit for pronounced inhibition of both primary and distant 4 T1 tumors, with a high primary tumor growth inhibition rate of 99.9%, and significantly suppressed distant tumor progression by promoting dendritic cell maturation, M1 macrophage polarization, cytotoxic T lymphocyte infiltration, and memory T cell generation. Overall, this study presents a rational design for the multidimensional cGAS-STING activation via chemotherapy, PDT and pyroptosis, holding great translational promises for boosting cancer immunotherapy in clinical settings.

Effective recovery and recycling of the annually increased lithium iron phosphate battery waste aligns well with the global decarbonization goals, which is of great significance for resource security, environmental protection, and circular economy. At present, much efforts have been devoted for recycling lithium element in spent LiFePO4 cathode materials, while rarely focus on recovering the residual phosphate iron slag. Herein, we propose a novel sodium salt roasting-water leaching procedure to efficiently exploit the phosphorus (P) and iron (Fe) resources, in which the abundant P was extracted selectively and transformed into valuable Na3PO4 & sdot;12H2O. Thermodynamic calculations reveal that the interaction of NaOH and phosphorus iron slag at high temperature endows the transformation of FePO4 to into soluble Na3PO4, and the remaining Fe is collected as Fe3O4. Under the optimal working conditions, the leaching rate of P reached 94.11 %, while less than 1 % for Fe, Al, and Cu. Through subsequent separation and evaporation processes, high purity Na3PO4 & sdot;12H2O and Fe3O4 products can be obtained. This work offers a fresh and sustainable approach for the recovery of P and Fe resources in phosphate iron slag.

This study proposes a novel strategy to transform the inherently nonselective enhancement of micro-nano bubbles (MNBs) into highly selective flotation separation by modulating mineral surface roughness through targeted acid/alkali pretreatment. To address the challenging separation of lepidolite and albite, two minerals with similar surface properties, this approach exploits differential surface dissolution behaviors to regulate MNBs attachment efficiency. Micro-flotation tests, scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), and adsorption measurements were performed to systematically investigate the effects and mechanisms of acid/alkali pretreatment on the surface properties of the two minerals and their MNBs attachment behaviors. The results show that the introduction of MNBs alone enhances the flotation recovery of both lepidolite and albite but does not improve separation selectivity (recovery difference: 8.27% for micro-nano bubbles flotation vs. 6.72% for deionized water flotation). In contrast, acid/alkali pretreatment differentially alters surface roughness to enhance or inhibit MNBs attachment, greatly amplifying the flotation contrast: HCl pretreatment makes albite recovery 14.90% higher than lepidolite, while NaOH pretreatment makes lepidolite recovery 14.52% higher than albite. HCl pretreatment smoothens the lepidolite surface while roughening albite, whereas NaOH pretreatment roughens lepidolite and smoothens albite. Analyses of surface morphology and adsorption behavior further confirm that acid/alkali pretreatment optimizes MNBs attachment efficiency by regulating surface roughness, thereby intensifying the flotation separation performance.

Ion-adsorption rare earth ores (IRE-ores) are the primary source for heavy rare earth elements (HREEs). Conventional leaching with ammonium sulfate generates substantial secondary pollution and is increasingly restricted due to environmental concerns. This study investigates an environmentally friendly bio-chemical leaching approach using metabolite-based lixiviants produced by fungi (Penicillium sp. and Aspergillus ochraceus) isolated from mining areas biocrust. The effects of leaching parameters (fermentation time, reaction pH and solid-liquid ratio) and the underlying mechanisms were systematically examined. Optimal leaching conditions were obtained at pH 4.5 and a solid-liquid ratio of 1:4. A composite lixiviant, formulated by mixing acidified metabolites with 2% ammonium sulfate (5:4 volumetric ratio), achieved a maximum REEs recovery of 94.1%, while reducing chemical consumption by more than 50% compared with conventional leaching. Mechanistic analyses indicated that organic acids, siderophores, and polyamines facilitated REEs solubilization primarily through ion exchange and complexation reactions. Targeted experiments identified polyamines as the dominant contributors, with spermine and spermidine (10 mM) achieving leaching efficiencies of 76.3% and 80.9%, respectively. Sequential extraction of leach residues demonstrated a metabolite-induced redistribution of REEs from ion-exchangeable fractions to carbonate- and Fe/Mn oxide-bound phases, accompanied by preferential mobilization of HREEs including Y, Dy, and Gd. These findings highlight the synergistic role of fungal metabolites in achieving comparable REEs recovery with enhanced selectivity and reduced environmental impact, offering a sustainable alternative for rare earth leaching. This study provides a mechanistic basis and practical framework for incorporating microbial metabolites into rare earth leaching, offering a sustainable route toward green hydrometallurgical recovery of strategic mineral resources.

The adsorption of rare earth ions (RE3+) from rare earth ore leachate using ion-imprinted polymers has emerged as an efficient and sustainable strategy. In this study, a "microbead immobilized bacteria (SBC) and ionimprinted polymer (FECY)" interaction system was established. Under optimized process parameters, SBC + FECY was found to exhibit significantly higher adsorption efficiency for yttrium(III) (Y3+) than either adsorbent alone. Addition-sequence experiments demonstrated that SBC likely enhances the adsorption performance of FECY indirectly by regulating ionic concentrations in solution. The characterization results further indicate that SBC and FECY possess a mesoporous structure, which effectively increases the contact area between RE3+ and the adsorbent, thereby conferring excellent adsorption capacity. Based on selective adsorption experiments and characterization data, it was demonstrated that SBC enhances the highly selective adsorption of Y3+ by FECY through ion-imprinted sites, modulating the ionic environment. The quantum theoretical calculations were performed to optimize the composite structure of FECY and Y3+, thereby providing a comprehensive illustration of the adsorption behavior of FECY toward Y3+. Furthermore, transcriptomic analysis revealed that bacteria can sense external environmental changes and modulate the ionic environment at the gene-expression level, thereby influencing their response to ionic stress and their adsorption capacity for impurity ions. After five adsorption cycles, both SBC and FECY exhibited excellent reusability. This study presents a novel strategy for the green and highly selective adsorption of target RE3+ from complex rare earth leachates.

ABSTRACT In biological systems, certain fundamental biomacromolecules, such as proteins and DNA, fulfill specific biological functions via structural changes triggered by stimuli. Herein, we report the synthesis of two allosteric regulation metal−organic octahedra ( S1 and S2 ) with tailored cavities/windows. Both cages exhibit distinct aggregation‐induced emission (AIE) colors and quantum yields. Single‐crystal x‐ray diffraction reveals that S2 , featuring longer arms, adopts a denser π‐stacking arrangement, rationalizing its superior emissive properties. The kinetically driven multicomponent heteroleptic octahedral mixtures formed under ambient temperature assembly conditions transformed into self‐sorted S1 and S2 upon heating. The addition of competitive building blocks enabled the transformation from S1 to S2 . Notably, 365 nm light irradiation induces planarization of the COT units, driving a rapid structural transformation from three‐dimensional (3D) octahedra to two‐dimensional (2D) metal–organic nanosheets ( NS‐1 and NS‐2 ) within minutes. This work provides a novel approach for designing responsive systems and demonstrates broad potential applications in areas such as optoelectronics, targeted delivery, and smart materials.

Acid mine drainage (AMD) generated from pyritic waste-rock piles is a persistent environmental challenge. Although sulfate-reducing bacteria (SRB) have shown potential for AMD remediation, the lack of cost-effective carbon sources remains an important constraint on their large-scale application. In this study, an integrated system consisting primarily of municipal sludge, forest soil and SRB-containing microbial inoculum was further evaluated at pilot scale for the passivation of pyritic waste rock. In the amended cell, leachate pH increased from approximately 3 to ≥6.8, while dissolved Fe decreased to ∼0.01 mg L⁻¹ and sulfate concentrations stabilized at 15–100 mg L⁻¹. Mineralogical and surface analyses showed a significant reduction in sulfate-bearing secondary minerals, enrichment of reduced Fe and S species, and the development of carbon-rich surface coatings on pyrite-bearing materials. Microbial community analysis further revealed increased microbial diversity and a marked shift from communities enriched in Fe/S-oxidizing taxa, including Acidiferrobacter, Leptospirillum, and Sulfobacillus, toward communities containing higher abundances of taxa previously associated with anaerobic Fe-S transformations, including Desulfitobacterium, Desulfosporosinus, and Proteiniclasticum, together with increased microbial network connectivity. These coupled changes were consistent with the establishment of a more reducing and passivating geochemical environment, which effectively suppressed acid generation and Fe and sulfate release. Follow-up observations at 90 and 180 days further showed that circumneutral pH and relatively low Fe and sulfate concentrations were maintained during the monitoring period. Overall, this approach provides promising pilot-scale evidence for the source-oriented management of pyrite-rich mine wastes and the beneficial reuse of municipal sludge as a carbon-rich amendment.

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 (Delta G=-519.429 kJ/mol at 50 degrees C), leading to inefficient copper utilization.

Traditional inorganic leaching agents leave residues in ore bodies during the extraction of ion-adsorbed rare earth ore (IAREO), causing environmental pollution. As a typical organic acid, citric acid (CA) not only exhibits excellent leaching capabilities for rare earth elements (REEs) but also can be degraded by soil microorganisms, making them more environmentally friendly. This study introduced CA into the leaching process of IAREO, improving the REEs leaching process. Column leaching experiments were conducted to investigate the mass transfer and solution seepage patterns of REEs. The results demonstrate that the CA-MgSO4 composite leaching agent achieves significantly higher REEs leaching efficiency than the single magnesium sulfate (MgSO4) leaching agent while significantly reducing the use of MgSO4. The REEs leaching efficiency reaches 77.95% in the CA-MgSO4 system (0.02 mol/L CA + 0.005 mol/L MgSO4), comparing the 77.52% in the single MgSO4 leaching system (0.2 mol/L MgSO4). The composite leaching agent reduces the use of MgSO4 (from 0.2 to 0.005 mol/L) while ensuring excellent REEs leaching efficiency. Visual Minteq calculation results indicate that CA forms RE-citrate complexes with REEs in the solution, reducing the activation energy of ion exchange reactions, thereby promoting the leaching of REEs. The rare earth content in each phase of the tailings further confirms that CA in composite leaching agents promotes the leaching of REEs in the ion-exchangeable phase, colloidal sediment phase, and mineral phase. In the IAREO leaching process, ion exchange reactions are the primary factor influencing ore body permeability. The addition of CA accelerates the progression of ion exchange reactions, thereby causing more pronounced changes in the solution permeability coefficient and reducing ore body permeability. Additionally, increasing temperature or hydraulic gradient accelerates the diffusion of the leaching agent within the ore body, which can lead to a decrease in the leaching efficiency of REEs. This study provides new insights for green and efficient rare earth mining technology.

The extraction of ion-adsorption rare earth (IARE) ores is a research focus due to its valuable heavy rare earth elements (REEs). One of the most common extraction methods is in-situ leaching using (NH4)2SO4, for which a concentration of approximately 2.0 90 % is required in practice. However, this results in significant ammonia nitrogen pollution of the environment. This study focuses on reducing consumption of this leaching agent. We selected citric acid, a readily available, naturally biodegradable, bio-based organic acid, and blended it with (NH4)2SO4 to leach IARE ores. Experiments involving column leaching and barrel leaching show that using a (NH4)2SO4-citric acid leaching agent improves REEs leaching efficiency by 20-40 %, compared to using pure (NH4)2SO4 alone. From a mechanistic perspective, experimental evidence demonstrates that citric acid promotes the leaching of REEs from IARE ores through three mechanisms. Firstly, the protons in citric acid weaken the double electric layer of the IARE ores, thereby facilitating the mass transfer of NH4+ and RE3+ ions. Secondly, citric acid reduces and decomposes iron colloidal oxide, releasing the REEs it contains. Finally, citric acid forms complexes with RE3+ ions, neutralizing their charge and reducing the probability of REEs being re-adsorbed onto the clay surface. This work paves the way for the further industrial application of organic matter in the leaching of IARE ores, and provides a new approach on the clean and efficient extraction of IARE ores.

Efficient separation of Cu-Mo sulfide minerals from moraine materials remains a major challenge for low-grade, high-moraine Cu-Mo ores. Fine-grained muscovite induces severe slime coating and gangue entrainment, thereby markedly reducing flotation selectivity. In this work, a biodegradable polymer depressant, polyaspartic acid (PASP), was employed to regulate Cu-Mo sulfide flotation under muscovite interference conditions. Microflotation tests, particle size distribution analysis, zeta potential measurements, SEM-EDS observations, contact angle measurements, and XPS analyses were conducted to clarify the dispersion behavior, slime-coating mechanism, and selective adsorption characteristics of PASP. The results demonstrated that PASP selectively depressed muscovite at relatively low dosages while exerting negligible influence on the floatability of chalcopyrite and molybdenite. Notably, at a dosage of 15 mg/L, PASP reduced muscovite recovery by 43.07% and 31.23% more effectively than sodium silicate and sodium hexametaphosphate, respectively, demonstrating superior selective depression efficiency under moraine interference conditions. Particle size distribution and zeta potential analyses confirmed that PASP effectively weakened heterocoagulation and electrostatic attraction between muscovite and sulfide minerals, thereby suppressing slime coating and improving slurry dispersion stability. SEM-EDS and contact angle analyses further revealed that PASP significantly reduced muscovite deposition on sulfide mineral surfaces while maintaining the hydrophobicity of chalcopyrite and molybdenite. High-resolution XPS analysis further indicated that PASP adsorbed onto muscovite mainly through coordination between carboxylate groups and surface Al-OH sites, forming a stable hydrophilic adsorption layer. Overall, PASP provides a low-dosage, highly selective, and biodegradable depressant strategy for mitigating muscovite-induced slime coating and improving the flotation separation of Cu-Mo sulfide ores under moraine interference conditions.

To explore the mechanism of chalcopyrite bio-oxidation in acid mine drainage (AMD), a two-factor, three-level chalcopyrite bio-oxidation experiment was designed to assess the effects of visible light and pyrrhotite, which are common environmental factors that influence AMD. Bio-oxidation results, mineral surface morphology, mineralogical phase, elemental composition and electrochemical analyses revealed that visible light and pyrrhotite promoted chalcopyrite bio-oxidation, facilitating enhanced copper release and iron/sulphur oxidation and dissolution. The results demonstrated that visible light contributed to maintaining suitable oxidation–reduction potential and eliminating passivator S0. Meanwhile, pyrrhotite enhanced mineral redox activity of chalcopyrite and photoelectron transfer, thus promoting chalcopyrite leaching. In addition, a considerably enhanced interaction between Acidithiobacillus ferrooxidans and chalcopyrite facilitated ferrous iron oxidation, iron/copper release and sulphuric acid generation.

The fragility of the global rare earth supply chain and the urgent demand for sustainable exploitation have driven intensive research into green and high-efficiency extraction technologies. Bioleaching technology, distinguished by its environmental compatibility and resource adaptability, has emerged as a transformative alternative to conventional chemical leaching methods. This study focuses on the multiphase utilization of ion-adsorption rare earth ores by leveraging Penicillium sp. fermentation broth to promote MgSO4-mediated leaching through a biologically enhanced chemical process. The objectives were to elucidate the rare earth leaching mechanisms under bio-promoted chemical processes and to optimize strain cultivation and leaching parameters. Untargeted metabolomics was applied to delineate dynamic changes in differential metabolites before and after leaching, while Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were utilized to clarify metabolite-mineral interfacial interactions. The results demonstrated that the composite system achieved a rare earth recovery rate of 93.79 % under optimal conditions (liquid-to-solid ratio of 4:1, 6-hour leaching), significantly outperforming conventional chemical leaching. Metabolomic analysis revealed a multifunctional interaction network involving organic acid-mediated proton attack, lipid molecule-driven interfacial modification, and benzenoid compound-regulated redox balance. This study demonstrates that the fermentation broth of Penicillium sp. significantly enhances MgSO4-mediated leaching efficiency of ion-adsorption rare earth ores, thereby offering a sustainable pathway to address resource and environmental challenges in rare earth industries.

This study aims to clarify the influence mechanism of air-water-mineral three-phase flow behavior on separation efficiency in a graphite flotation column, addressing the issues of over-breaking of coarse graphite flakes and low recovery of fine particles caused by mismatched flow fields and operating parameters in traditional flotation columns. Using CFD numerical simulations based on the Eulerian multiphase flow model, the standard k-epsilon turbulence model, and scalable wall functions, the effects of feed velocity (0.8-2.4 m/s) and aeration velocity (1-5 m/s) on the flow field structure, gas holdup distribution, and weighted average bubble-particle collision probability inside the column were systematically analyzed. Key quantitative results show that under the synergistic condition of a feed velocity of 2 m/s and an aeration velocity of 3 m/s, an internal circulation flow field conducive to particle retention is formed. Under these conditions, the gas holdup in the collection zone reaches an optimal range (0.26-0.27), and the weighted average collision probability increases by approximately 22% compared to the baseline condition. Aeration velocity shows a significant positive correlation with gas holdup in the collection zone (similar to 0.235 at 1 m/s, rising to similar to 0.285 at 5 m/s). While an increase in feed velocity reduces the overall gas volume fraction, it enhances turbulence and promotes uniform bubble dispersion through the spatial distribution of regions with high collision probability from the upper part to the upper-middle part of the column and improves the uniformity of distribution. The novelty of this study lies in being the first to quantitatively reveal, through CFD simulation, the coupled regulatory effects of feed velocity and aeration velocity on the stratified flow field structure and mineralization probability in a flotation column and to identify the key optimization threshold of "2 m/s feed velocity". The practical significance is that it provides a clear theoretical basis and operational window for energy saving, consumption reduction, and process intensification in industrial flotation columns. It offers directly applicable parameter optimization strategies for the efficient recovery of fine-flake graphite and the protection of coarse flakes.

To mitigate ammonium pollution and soil acidification associated with traditional (NH4)2SO4 leaching of ionic rare earth ores, a synergistic approach utilizing low-concentration (NH4)2SO4 and acetic acid (HAc) was proposed to enhance ion exchange efficiency while minimizing ammonium consumption. Leaching efficiency and ammonium consumption were evaluated through comparative leaching experiments. Under optimized co-leaching conditions (pH 4-5, 30 degrees C, and 1 h), rare earth elements (REEs) leaching efficiency of 88.92% was achieved. This represents a 13.36% increase over single (NH4)2SO4 leaching (0.02 mol/L). Compared to the conventional single (NH4)2SO4 system (requiring 0.03 mol/L for 90% efficiency), ammonium consumption was reduced by 33.3%. Characterization revealed enhanced surface roughness and significantly increased negative charge on the ore in the synergistic system, facilitating RE3+ exchange. This study provides a sustainable leaching approach, reducing the environmental impact of traditional REE extraction through the rational use of inorganic lixiviants.

Ion-adsorption rare earth (IARE) ores constitute over 90% of global heavy rare earth element (REEs) reserves. However, the process of extracting this substance confronts with persistent metallurgy challenges, including elevated levels of ammonium input, protracted leaching cycles, inadequate impurity control, and recurrent slope instability. In recent years, an increasing number of scholars shift attention to the innovative research and application of leaching agents and methods within in-situ leaching processes, achieving significant advancements. The innovations in this area need systematically summering. In this work, we evaluate the mineral characteristics and extraction process of IARE ores from the root. The following key innovations in leaching agents are discussed: firstly, the reduction of ammonium salt inputs; secondly, the suppression of impurity leaching; thirdly, the enhancement of the leaching efficiency of non-ionic state REEs; fourthly, the strengthening of leaching solution permeability; and fifthly, the inhibition of clay expansion. Furthermore, the potential of non-mainstream novel leaching methods, including biological leaching and exogenous field-enhanced leaching techniques, is discussed. The purpose of this review is to provide guidance on the green, sustainable, and efficient extraction of IARE ores.

This study evaluated the ecological toxicity of bioleachate produced by Sulfobacillus thermosulfidooxidans on the model microorganism Escherichia coli and the model plant Arabidopsis thaliana. The results demonstrated that the low pH and microbial metabolites in the leaching liquor significantly inhibited E. coli growth. Transcriptomic analysis revealed that E. coli adapted to stress by regulating genes such as waaH and glpD. In plant experiments, the leaching liquor markedly suppressed seed germination and seedling growth in A. thaliana, particularly root development, with S0 or FeS2 as substrates causing cotyledon developmental defects. Oxidative stress was identified as a potential key mechanism underlying growth inhibition. Notably, lithium accumulation in shoot tissues was dose-dependent and higher than in roots, indicating a potential risk of trophic transfer. This study evaluated the ecological toxicity of bioleachate, identifying key risk factors such as low pH and lithium accumulation. It thereby provides important scientific evidence for the clean production of biometallurgy processes, the ecological safety management of leaching effluents, and the full-chain environmental regulation of lithium resource development.

Urea electrolysis represents a promising low-energy route to sustainable hydrogen production by replacing the anodic oxygen evolution reaction with the urea oxidation reaction (UOR). However, its practical application is limited by sluggish reaction kinetics and insufficient catalyst stability. Herein, we develop a nitrogen-doped nickel phosphide electrocatalyst (N-Ni2P) and demonstrate its multiscale regulatory role in electronic structure, phase transition behavior, and interfacial properties. Combining in situ spectroscopy, operando mass spectrometry, and theoretical modeling, we elucidate that nitrogen doping triggers asymmetric charge redistribution and elevates the Ni electrophilicity, which synergistically lowers the energy barrier for electrochemical reconstruction into gamma-NiOOH and facilitates interfacial charge transfer. These effects collectively promote the adsorption of key intermediates, improve redox reversibility, and reconstruct the electric double layer, ultimately steering the reaction pathway toward selective urea oxidation. As a result, the N-Ni2P catalyst exhibits a low UOR overpotential of 1.347 V at 100 mA cm-2 and achieves 61.9 % urea degradation within 1 h. When configured in a solar-driven urea-assisted water splitting system, it enables stable hydrogen production at 1.604 V. This work offers valuable insights into the electronic and phase engineering of robust electrocatalysts for sustainable energy conversion.