Iron and lithium were recovered from the cathode material of spent lithium iron phosphate battery using choline chloride,ascorbic acid,and ethylene glycol as a ternary deep eutectic solvent.The effects of the molar ratio of choline chloride/ascorbic acid/ethylene glycol,liquid volume to solid mass ratio,reaction temperature and time on the leaching rate of iron and lithium were investigated.The leaching mechanism was discussed through kinetic analysis and SEM characterization.The results show that under the optimal leaching conditions of choline chloride/ascorbic acid/ethylene glycol molar ratio of 1∶1∶3,liquid volume to solid mass ratio of 0.1 mL/1 mg,reaction temperature of 80 ℃ and reaction time of 1 h,the leaching rates of lithium and iron can reach 96% and 98%,respectively.The leaching process is mainly controlled by chemical reactions.The method is efficient and environmentally friendly,and can recover iron and lithium from spent lithium iron phosphate batteries.

Address to the issue of high fluorine content in the flotation concentrate of a super-large Beryllianite-type uranium-beryllium co-associated ore in Xinjiang,the mineral and elemental composition,as well as the mineral dissemination characteristics were studied.Flotation process of "floating fluorite first and then beryllium" was adopted for flotation.Grinding fineness and flotation reagent system were optimized through systematic flotation condition tests. The results show that for the raw ore with a beryllium grade of 0.435% and a grinding finness of -325 mesh accounting for 93%,under the conditions of 1.5 kg/t for sodium silicate in roughing,2 kg/t for NaOH,700 g/t for oxidized paraffin soap in roughing,and 500 g/t for swept oxidized paraffin soap in scavenging,The technical indicators of flotation with beryllium grade of 3.36% and recovery rate of 81.99% are obtained. The process can achieve effective enrichment of beryllium minerals.

Preparation of alumina from fly ash by hydrochloric acid method is one of the processes with significant industrial application potential.Therefore,studying the ionic structure in acid leaching solution of fly ash is of great significance for iron removal process in the method.The ionic structure of the AlCl₃-FeCl₃-FeCl₂-HCl-H₂O system in hydrochloric acid leaching solution of fly ash at pH values of 1.0,1.5,and 2.0 was investigated by combining thermodynamic calculation,quantum chemical calculation,and Raman spectroscopy. The results show that at pH = 1.0,the main forms of Fe and Al complex ions in the system are [FeCl]⁺,[FeCl₂]⁺ and [AlCl]²⁺;when the pH rises to 1.5 and 2.0,[FeCl]⁺,[FeCl₂]⁺ and [AlCl]²⁺ transform into hydrolysis products such as [FeOH]⁺,[FeOH]²⁺ and [AlOH]²⁺ with hydroxyl ligands.The wave function analysis results indicate that at low pH,due to the high concentration of chloride ions,the chloride complexes are more stable.As the pH increases,the concentration of hydroxide ions increases,and the formation of high-coordination hydroxyl complexes becomes easier due to their higher metal-oxygen bond order and lower Gibbs free energy.

The recovery of valuable components manganese and lithium from retired lithium manganese oxide batteries by carbon-thermal reduction—acid leaching combined recovery process was studied.The mixed powder of lithium manganese oxide and graphite was roasted by carbon thermal reduction,and the roasted products were characterized by XRD,XRF,SEM,TG-DTA and other technologies.The results show that the best effect is achieved by roasting at 650 ℃ for 180 min,and the lithium manganese oxide in the roasted product is completely converted into manganese monoxide and lithium carbonate.The lithium carbonate in the sample powder can be extracted by water leaching,and the leaching rate of lithium carbonate is 86.15%.Manganese ions are extracted by acid leaching of sulfuric acid.Under the acid leaching conditions of acid leaching concentration of 3.5 mol/L,acid leaching temperature of 60 ℃,acid leaching time of 3 h,and liquid volume to solid mass ratio of 8/1,the highest leaching rate of manganese ions is 88%.The method can achieve the purpose of synchronous and efficient recovery of manganese and lithium from cathode materials,and has certain application value.

Secondary aluminum dross (SAD) is a hazardous waste generated during aluminum resource recycling,containing aluminum,alumina,aluminum nitride,fluorides,chlorides,and other components. It exhibits strong chemical reactivity and leaching toxicity,making its resource utilization and environmentally friendly recovery highly significant. The denitrification of SAD by alkaline roasting,the extraction of aluminum from the roasted residue via water leaching,and the defluorination of the leachate using CaCl₂ were studied.The phase transformation,elemental distribution,and microstructure of the roasted dross were analyzed by XRD and SEM-EDS.The results show that under optimal alkaline roasting conditions of m(NaOH)∶m(SAD)=1.1,roasting temperature of 800 ℃,and roasting time of 120 min,the nitrogen removal rate can reach 98.77%.Under the best water leaching conditions of leaching temperature of 70 ℃,liquid volume to solid mass ratio of 14∶1,and leaching time of 80 min,the aluminum leaching efficiency is 91.83%,with Al,AlN,and Al₂O₃ in the roasted residue being mostly converted into soluble NaAlO₂.For fluorine removal from the leachate,CaCl₂ was employed.The results indicate that under the conditions of n(Ca²⁺)∶n(F^-) = 0.7,reaction temperature of 50 ℃,and reaction time of 90 min,the defluorination rate can reach 94.87%. The fluorine removal residue primarily consists of CaF₂ and a small amount of unreacted CaCl₂,which can be used as a flux in metal smelting.The process achieves efficient aluminum extraction from SAD while removing nitrogen and fluorine,fulfilling the objectives of harmless treatment and resource recovery.

Extraction of copper from refractory copper oxide ore using a roasting—acid leaching process was investigated.The effects of roasting and leaching conditions on the copper leaching rate were examined. The results show that under the optimal conditions of -200 mesh grinding fineness of 70%,roasting temperature of 850 ℃,roasting time of 1 h,coal addition of 8%,liquid volume to solid mass ratio of 2/1,H₂SO₄ concentration of 15%,leaching temperature of 60 ℃ and leaching time of 3 h,the copper leaching rate can reache 91.03%.The process is demonstrated to be economically efficient for extracting copper from refractory copper oxide ore and is considered to have potential for broader application.

To address fiber shrinkage embrittlement and consequent mechanical degradation during surface modification of polyamidoxime (PAO) adsorbents,a "core-shell heterostructure stress transfer" strategy was proposed.A coaxial electrospinning technique was employed to fabricate PS@PAO nanofibers with a polystyrene (PS) flexible core and rigid PAO shell.Microstructural analysis results show that PS@PAO exhibits uniform core-shell architecture (≈200 nm diameter, ≈50 nm thickness) with a specific surface area of 6.22 m²/g,representing a 38% enhancement over pristine PAO fibers. Mechanical testing results demonstrate 13.8% and 30.1% improvements in tensile strength (0.66 MPa) and Young's modulus (34.84 MPa),respectively.Dynamic contact angle measurements show that favorable hydrophilicity with water contact angle decreasing from 30° to 21° within 1 s. When PS@PAO is used to adsorb uranium from seawater with pH of 8.0 and uranium mass concentration of 16 mg/L for 48 h,the adsorption capacity is 34.14 mg/g. Adsorption kinetics analysis results indicate compliance with the pseudo-second-order model,with chelation between uranyl ions ( \mathrm{U} {\mathrm{O}}_2^{2+}) and amidoxime groups identified as the dominant mechanism.Through comprehensive investigation of material architecture,uranium extraction performance,and adsorption mechanisms,this study can provide theoretical foundations and scalable fabrication guidance for developing high-stability marine uranium extraction materials.

In view of the problems of high energy consumption,high equipment requirements and low flexibility in recovering rhenium from processing waste by traditional pyrometallurgical processes,the electrochemical enhanced leaching—precipitation crystallization method was studied to recover high-purity KReO₄ crystals from rhenium secondary resources.The results show that when 22%~24% HNO₃ solution is used as the electrolyte,there is no obvious passivation during the electrolysis process,and the energy consumption is stable at about 3.0 kWh/kg.During the electrolysis,Re atoms at the hexagonal lattice sites on the anode surface lose electrons,combine with hydroxyl groups and transform through low-valent oxidation states of Re to bridge oxygen connected Re(Ⅱ),and finally enter the electrolyte in the form of \mathrm{R} \mathrm{e} {\mathrm{O}}_4^{-} after reacting with the acid.When potassium salt is used as the precipitant to recover Re elements in the electrolyte,under the conditions of crystallization temperature of 25 ℃,precipitant flow rate of 6 mL/min,stirring rate of 500 r/min and crystallization time of 30 min,the precipitated KReO₄ crystals are in the shape of polyhedral spindle,with good uniformity in particle size,high recovery rate and purity of 99.95%,which can meet the requirements for hydrogen reduction to prepare metallic rhenium.The method can effectively recover rhenium processing waste and has certain promotion value.

The determination of alkyl mercury in water by distillation—purge and trap/gas chromatography-cold atomic fluorescence spectrometry was studied. The detection limit,precision and accuracy of the method were determined,and the factors affecting the effect of distillation and the optimum test conditions were determined.The results show that the detection limit of methymercury is 0.003 1 ng/L and that of ethylmercury is 0.002 8 ng/L.The adding standard recovery rates of both are 99.4%~104%,and the relative standard deviations(RSD) are 1.02%~1.34%. The factors affecting distillation effect are hydrochloric acid and saturated copper sulfate adclition.For 40 mL of pure water,the optimal addition amounts of concentrated hydrochloric acid and saturated copper sulfate are 80 and 200 μL,respectively.When the addition amount of alkylmercury are 4.00,40.0 and 400 pg,the recovery rates are all in line with the quality control requirements. The recovery rate of alkyl mercury adding standard can be significantly improved after distillation treatment in actual lake water.

The removal of uranium bound to organic matter in real uranium-contaminated soil from a certain mining area was studied by using a combined oxidation washing process.The removal effects of uranium by two different new oxidation-washing systems(EDTA-H₂O₂ and SDS-H₂O₂)were compared.The effects of key parameters such as pH,liquid volume to solid mass ratio,oxidant concentration,and washing agent concentration on removal rate of uranium were investigated through single-factor experiments.The process conditions were optimized by response surface methodology,and the optimal conditions were determined.The results show that the removal rate of uranium by the EDTA-H₂O₂ system is 52.8% under the conditions of pH=4,liquid volume to solid mass ratio of 15/1,H₂O₂ concentration of 3%,and EDTA concentration of 100 mmol/L.After optimizing the process conditions by response surface methodology,the removal rate can be increased to 56.3%.The removal rate of uranium by the SDS- H₂O₂ system is 26.8% under the conditions of pH=4,liquid volume to solid mass ratio of 10/1,H₂O₂ concentration of 3%,and SDS concentration of 20 mmol/L.After optimizing the process conditions by response surface methodology,the removal rate can be increased to 29.5%.The removal effects of the two oxidation-washing systems are significantly better than those of single washing agents and single oxidants (EDTA 24.12%,SDS 0.66%,H₂O₂ 13.81%).The process can effectively break the complex of organic matter and uranium,significantly improve the remediation efficiency of real uranium-contaminated soil,and provide a feasible solution for uranium pollution control in mining areas.