The extraction and separation of heavy rare earths (HREs) by a mixed extraction system composed of N, N′-di(2-ethylhexyl)aminomethyl phosphonic acid mono-2-ethylhexyl ester (HEDEAP, H₂A₂), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (P507, H₂B₂) and n-heptane were investigated. The results show that the HEDEAP-P507 mixed system exhibits positive synergistic effects on HREs extraction. Under optimal conditions (HEDEAP molar fraction of 0.4, pH 2.0, phase ratio(V_o∶V_a) of 1∶1 and temperature of 25 ℃), the maximum synergistic coefficient for Lu(Ⅲ) extraction can reach 1.42. The separation factors for Y/Ho, Er/Y, Tm/Er, Yb/Tm and Lu/Yb are determined as 1.67, 1.76, 4.5, 1.67 and 2.11, respectively, surpassing those of the single P507 system. FT-IR analysis result reveals the participation of P—OH and P═O groups in coordination reactions. Slope analysis indicates the possible formation of REH₃A₂B₂Cl₂ as the synergistic complexes. The loading capacity of the mixed system containing 12 % HEDEAP and 18 % P507 for Lu(Ⅲ) is measured to be 32.4 g/L (calculated as Lu₂O₃). The HREs loaded in the mixed system is easy to be stripping. The Lu(Ⅲ) stripping rate is 80% with 1.0 mol/L HCl, and the stripping acidity required for the same stripping rate is much lower than of P507 system (4.0 mol/L). Compared to the sole P507 system, the HEDEAP-P507 mixed system significantly enhances extraction selectivity for HREs while reducing stripping acidity requirements, demonstrating substantial scientific significance and promising application potential for selective separation of HREs.

To enhance the resource utilization rate of fine-grained refractory gold ores, a combined process of flotation and leaching was studied for the extraction of gold from the Kamator gold ore in Kyrgyzstan (Au 3.07 g/t, Ag 20.40 g/t). The results show that a gold concentrate with a grade of 28.57 g/t can be obtained through closed-circuit flotation, with a gold yield and recovery rate of 8.05% and 72.47%, respectively, and the gold grade of the flotation tailings is 0.95 g/t. Under suitable conditions, the average gold leaching rate of the flotation tailings can reach 83.16%, with a relative gold recovery rate of 22.89% compared to the original ore, and the gold grade of the leaching residue is 0.16 g/t. By adopting the flotation-leaching process, the comprehensive gold recovery rate can reach 95.36%. This method can effectively recover gold from this type of ore.

During the biological leaching process, leaching microorganisms are relatively sensitive to environmental factors such as the initial pH and ore-pulp ratio. Taking a sandstone type uranium deposit in Inner Mongolia as the research object, by analyzing the pH, REDOX potential (Eh), iron ion concentration and uranium leaching rate of the leaching solution, the influence of the initial pH and ore-pulp ratio on the uranium leaching rate was discussed. The results show that when the initial pH is 1.4 and the ore-pulp ratio is 10%, the biological leaching effect of uranium is the best, and the uranium leaching rates reach 95.63% and 94.22%, respectively. An appropriate initial pH can reduce the formation of iron precipitation and maintain the activity of mixed Acidithiobacillus ferrous oxide (At.f) and Thiobacillus thiooxidans (T.t). The optimized ore-pulp ratio can enhance the mass transfer efficiency and promote leaching. The research can provide an important basis for optimizing the bioleaching process of sandstone-type uranium ores, and the research results can offer theoretical basis for the enhanced bioleaching of sandstone-type uranium ores in Inner Mongolia region.

Aiming at the three wastes problem existing in the traditional hydrometallurgical tungsten smelting process, based on the analysis of the complexation coordination characteristics of oxalic acid and tungstic acid, the selective extraction of tungsten from crude tungstic acid using oxalic acid was studied. To clarify the dissolution reaction kinetics mechanism of tungstic acid in oxalic acid, taking pure tungstic acid as the research object and oxalic acid solution as the leaching agent, the dissolution rules of tungstic acid under different temperatures, oxalic acid concentrations and stirring speeds were investigated. The dissolution kinetics of tungstic acid in oxalic acid solution was studied by the equal leaching rate method. The results show that the apparent activation energy of this reaction is 48.9 kJ/mol. Controlled by the chemical reaction, the reaction order of oxalic acid concentration is 1.103 5.

The synthesis of micrometer-sized Li_0.08La_0.64Nb₂O₆ anode material for lithium-ion batteries via a high-temperature solid-phase method was investigated and its structure and electrochemical properties were analyzed and discussed by X-ray powder diffraction (XRD) and cyclic voltammetry (CV). Structural characterization reveals that the material crystallizes in an orthorhombic system (space group Pmmm) and its ordered A-site defect layers, synergistically coupled with the rigid ［NbO₆］ octahedral framework, construct percolating lithium-ion transport channels. Electrochemical testing results demonstrate that at a current density of 0.05 A/g, the material delivers a discharge specific capacity of 355.57 mAh/g after 100 cycles, with a capacity retention rate of 94.4%. The capacity retention remains at 84.9% after 3 000 cycles at a high rate of 1 A/g. Analysis of the pseudocapacitive contribution indicates a pseudocapacitive contribution rate of 88% at a scan rate of 1 mV/s. The kinetic index b ranges from 0.771 to 0.895, confirming that its charge storage mechanism is predominantly surface-controlled pseudocapacitance. Galvanostatic intermittent titration technique (GITT) measurements yield a lithium-ion diffusion coefficient of 5.79×10^-11 cm²/s, indicating excellent ion transport capability. The research results can provide theoretical references for the development of A-site defective niobium-based perovskite materials and their application in lithium-ion batteries.

In the geological disposal of high-level radioactive waste, the mineral composition of surrounding rock and buffer materials is complex. Therefore, research is conducted from the perspective of rock composition to simplify research process of nuclide migration in geological media. The adsorption behavior of common minerals such as feldspar, illite and kaolinite on Se(Ⅳ) in granite, clay rock and bentonite was studied through batch experiments. The results show that under different conditions such as contact time, solution pH, ionic strength, initial mass concentration of Se(Ⅳ), solid mass to liquid volume ratio and temperature, the variation laws of the adsorption rates of Se(Ⅳ) by the three minerals are consistent, while the adsorption capacity of illite for Se(Ⅳ) is slightly higher than that of the other two minerals. The adsorption processes of Se(Ⅳ) by the three minerals all follow the pseudo-second-order kinetic model, which conforms to the Freundlich isotherm model, and the adsorption process is a spontaneous endothermic reaction. It is found through SEM, XRD and FT-IR characterization that there are no obvious changes in the three minerals before and after the adsorption of Se(Ⅳ).

In order to determine the solid phase distribution law of UO₂ particles during the gas-liquid-solid fluidization process, Fluidization behavior of nickel powder (simulating catalyst) and alumina (simulating UO₂ product) in a cold model experiment of a magnetic field-assisted gas-liquid-solid three-phase fluidized bed, with a focus on separation characteristics under magnetic field regulation were systematically investigated. The results show that in the absence of a magnetic field, the axial solid content distribution of alumina particles varies significantly with the gas flow rates (5-40 L/min). Under low gas flow rates (5-20 L/min), a high-concentration deposition zone is formed at the bottom of the bed, and the larger the particle size, the more obvious the deposition effect. Under medium and high gas flow rates (25-40 L/min), large bubbles break to enhance axial mixing, but the solid content at the top is still lower than that at the bottom. Nickel powder shows significant differences due to its high-density characteristics. Fine particles (200-300 mesh) require a gas flow rate of ≥15 L/min to achieve quasi-uniform dispersion, while coarse particles (100-200 mesh) remain deposited at the bottom of the bed even when the gas flow rate reaches 40 L/min. After the application of a magnetic field, nickel particles gradually accumulate in the lower part of the bed as the magnetic field intensity increases, forming magnetic agglomerated "apparent large particles" that are stably deposited near the gas distribution plate, while non-magnetic alumina floats up with the liquid flow. Under the same magnetic field the solid content ratio of nickel powder to alumina to increase from top to bottom, but the ratio drops rapidly with the strengthening of the magnetic field, indicating a significant aggregation effect of magnetic particles. The research results verified the dynamic separation efficiency of magnetic field-assisted fluidized beds for magnetic catalysts and non-magnetic products, clarified the key parameters of gas flow rate, magnetic field intensity and particle matching, and provided theoretical support for the design of continuous reactors in uranium chemical industry.

Adsorption and removal of iron from high-concentration sulfuric acid solution using sulfonated phosphonic acid resin and amino phosphonic acid resin was studied. The influence of sulfuric acid concentration on the adsorption of Fe²⁺ and Fe³⁺ by the two resins was investigated. The adsorption kinetics and adsorption isotherms of Fe³⁺ were analyzed. The effects of hydrochloric acid concentration and different additives on the elution of Fe³⁺ were explored. The structural characteristics of the resin before and after adsorption were analyzed by infrared spectroscopy comparison. The results show that the adsorption capacities of the two resins for Fe³⁺ in high-concentration sulfuric acid solution are 30 mg/g and 25 mg/g, respectively, and they hardly adsorb Fe²⁺. The adsorption processes of Fe³⁺ by the two resins conform to the pseudo-second-order kinetic model and the Langmuir isothermal adsorption model. The reactions are endothermic and mainly chemical adsorption, which belongs to monolayer adsorption. High-concentration hydrochloric acid can desorb Fe³⁺ loaded on two types of resins, and acidic solutions with thiourea or ascorbic acid as additives can also achieve complete desorption of Fe³⁺ in sulfonated phosphonic acid resins. The results of infrared spectroscopy analysis show that the sulfonic acid and phosphate groups of sulfonated phosphonic acid resin, as well as the amino and phosphate groups of amino phosphonic acid resin, all participate in the adsorption of Fe³⁺. The method has a good effect on iron removal and has certain application prospects.

The removing of fluorine from the new liquid of the zinc smelting system by chemical precipitation method using a new type of composite defluorination agent D-3 was studied. The effects of reaction temperature, reaction time, dosage of defluorination agent added and the initial pH of the new solution on the defluorination rate were investigated. The results show that the reaction time has the greatest influence on the defluorination rate, followed by the dosage of defluorination agent, then the reaction temperature, and the initial pH of the fluorine-containing new solution has the least influence. Based on the results of the single-factor test and combined with the actual production situation, the optimal fluoride removal conditions are determined as follows:the addition amount of D-3 defluorination agent is 40 times, the reaction temperature is 70 ℃, the reaction time is 1.0 h, and when the initial pH of the new fluorine-containing solution is approximately 5.0, the defluorination rate under the conditions is approximately 75%, and the residue rate is 12%. When the fluorine content in the new liquid exceeds 200 mg/L, the defluorination rate exceeds 75%, and the defluorination effect is better.

Extracting fluorine from aluminium electrolysis spent carbon anode by phase transformation roasting—water leaching process was studied. The effects of various factors during phase transformation roasting and water leaching on fluoride leaching rate were investigated. The results indicate that under the optimal conditions of alkali fusion temperature of 700 ℃, alkali fusion time of 2 h, alkali-to-material mass ratio of 1.25, insoluble cryolite is transformed into soluble sodium fluoride and sodium meta-aluminate phases. Under the optimal conditions of water leaching temperature of 65 ℃, liquid volume to solid mass ratio of 22/1, water leaching time of 2 h, the fluorine leaching rate achieve 95.86%. XRD analysis of the leached residue reveal that the remaining fluoride existed as calcium fluoride. The soluble fluorine mass concentration in the residue is 48 mg/L, which can meet the harmless requirements. The harmless and resourceful recovery of carbon residue can be achieved by converting the fluoride occurrence form through calcination and combining it with a one-step water leaching process. The method offers advantages such as a simple process flow, rapid reaction kinetics, high treatment efficiency, and promising industrial application prospects.

The hydrometallurgical process route of "alkaline conversion-acidic lead extraction-sulfuric acid lead separation" was studied for the separation and enrichment of lead from copper smelting slag. The principle of efficient transformation of lead in slag was mainly explored, and the effects of various factors in each process on the transformation, leaching and precipitation of lead were investigated. The optimal experimental conditions for each process were determined. The results show that by adding NaOH, the higher free alkalinity will cause PbSO₄ in the slag to enter the liquid phase in the form of plumbous acid, increasing lead loss and reducing recovery rate. In the acidic extraction stage, the reaction time and free acidity have a significant impact on the leaching rate. Under the conditions of free alkalinity of 15 g/L, liquid volume to solid mass ratio of 5/1, and temperature of 30 ℃, the alkaline transformation reaction is carried out for 3 h. Then, under the conditions of free acidity of 20 g/L, liquid volume to solid mass ratio of 5/1, and atemperature of 30 ℃, the slag are leached with nitric acid for 2 h. Finally, lead is precipitated with sulfuric acid under the conditions of a sulfuric acid coefficient of 0.8 to 1.0 and temperature of 30 ℃. The conversion rate and leaching rate of Pb in the slag can both reach over 95%. The process can efficiently separate and enrich lead from copper smelting slag, and the effect is good.

Three different types of deep eutectic solvents (DES) were prepared and used to modify Tieguanyin tea residue. The adsorption performance of the modified tea residue for methyl orange was investigated, and its thermodynamic adsorption behavior was explored. The results show that the adsorption effect of DES② modified tea residue composed of choline chloride/urea/malonic acid on methyl orange solution is better than that of DES① modified tea residue composed of sulfoxic acid/urea/choline chloride and DES③ modified tea residue composed of choline chloride/oxalic acid. The adsorption process of methyl orange by DES② modified tea residue is more in line with the Langmuir adsorption isothermal model. The adsorption process is endothermic, spontaneous and disordered.

To overcome the challenges of in-situ leaching uranium mining, such as limitations in real-time data analysis, lack of intelligent decision support, insufficient dynamic optimization capabilities, complexities in formulating real-time production strategies, and difficulties in full-lifecycle iterative optimization, a dynamic mining and intelligent management system for closed-loop in-situ leaching of uranium is proposed. The system’s fundamental concepts, key enabling technologies, structural components and operational framework are presented in detail. Based on the reactive transport model, the system focuses on dynamic data monitoring, data assimilation, and dynamic multi-objective production optimization, aiming to enhance the intelligent level and optimization management capabilities of in-situ leaching uranium mining. The construction and application of this system are expected to accelerate the digital and intelligent transformation of in-situ leaching uranium mining and provide a robust theoretical foundation support for the full life cycle development and management of uranium resources.

For the highly acidic extraction system of zirconium and hafnium, ceramic and PTFE baffles were selected and their hydrodynamic (dispersed phase holdup and droplet diameter) characteristics and mass transfer performance were compared and analyzed. The results show that the PTFE baffle, due to its strong hydrophobicity, is difficult to form droplets, but its holdup is significantly higher than that of the ceramic baffle. At low pulse intensities, the extraction efficiencies of the ceramic baffle and the PTFE baffle are comparable and increase with the increase of pulse intensity. When the pulse intensity increases to 10 mm/s, the ceramic baffle can achieve two theoretical stages of mass transfer, but the extraction rate of the PTFE baffle drops rapidly. By comparing the mass transfer performance of the baffles with that of the traditional Raschig ring packing, it is found that the extraction effect of the ceramic baffle is significantly higher than that of the Raschig ring packing, verifying the applicability of the baffle extraction column. Finally, a prediction model for the dispersed phase holdup, droplet diameter and mass transfer coefficient in the baffle extraction column was established. The research results can provide a theoretical basis for the design of zirconium and hafnium baffle extraction columns.

A layered optimization model of hydrometallurgy process based on deep learning is proposed. The model adopts hierarchical design, including process level optimization and process level optimization. At the process level, Transformer model is innovatively introduced to establish a nonlinear mapping model of material consumption and quality index, and optimize each process parameter with minimum material consumption as the goal. In the process layer, the innovative DDPG algorithm is introduced to adjust the operating variables and maximize the economic benefits of the whole process. In addition, generative adversarial network (GAN) is introduced to generate optimization samples to further improve the robustness of the optimization model. After the sodium cyanide and zinc powder additions are adjusted in real time by the Transformer optimization model, the gold production can be significantly increased and the material consumption cost can be significantly reduced. Compared with the benchmark test, the economic benefit increased by 15%-20%, the leaching rate and the replacement rate increased by 2%-4% respectively. The model is superior to the traditional deep learning method in terms of economic benefit, process stability and uncertainty adaptability, and can provide a new way for intelligent production in hydrometallurgical industry.

The precise determination of critical elements such as uranium and plutonium in spent nuclear fuel reprocessing workflows holds paramount significance for process optimization and safety assurance. Building upon international technological precedents, the LiF(200) doubly curved crystal optical element was optimized and selected, and the MWDXRF prototype for quantitative analysis of actinide elements was successfully developed. The results of the diffraction intensity and fluorescence characteristic experiments show that the instrument is feasible for the micro-trace-level analysis of actinide elements, and its detection limit for uranium determination is 18.97 μg/mL. The development of the device provides a new way for novel approaches to the simultaneous determination of trace/ultra-trace actinides in complex matrices.