Biometallurgy has drawn the attention of the academic community in recent years as an effective way to achieve in-situ resource utilization (ISRU) in future interstellar bases. However, the mechanism of interaction between Streptomyces and minerals is still unclear under the effect of microgravity. To investigate this issue, simulating the leaching of elements from minerals by Streptomyces sp. R76 under microgravity using clinostats was studied. The results show that the simulated microgravity environment significantly accelerated Streptomyces sp. R76's development, differentiation, and metabolic capacity, which is primarily manifested in the early development and differentiation of aerial hyphae and spores, as well as the increase in organic acid. Streptomyces sp. R76 can produce lactic acid and citric acid at concentrations of 8.6 and 0.17 mmol/L under simulated microgravity and 5.8 and 0.04 mmol/L under gravity, respectively. When Streptomyces sp. R76 is co-cultured with minerals, the leaching rate of rare earth elements under simulated microgravity is 3‰, the leaching rate of calcium is 0.11‰.The leaching rate of rare earth elements under gravity is only 0.33‰ and the leaching rate of calcium is 0.08‰.The lactic acid and citric acid produced by Streptomyces sp. R76 under microgravity conditions are important factors in promoting the leaching of calcium, silicon, and rare earth elements from minerals.

Preparation of a novel imidazole-based functional resin using polystyrene-divinylbenzene copolymer as the support by chloromethylation reaction and imidazole modification was studied. Adsorption properties and selectivity for uranium by the resin from acidic waste solution were systematically investigated. The results show that the equilibrium adsorption capacity of imidazole-based functional resin is 58 mg/g for uranium containing acidic solution with pH=5 and uranium mass concentration of 90 mg/L. Additionally, the resin has good tolerance to nitrate and chloride ions and high adsorption selectivity for uranium. When the mass concentrations of nitrate and chloride are 20 g/L and 5 g/L, respectively, the uranium adsorption capacity can also reach 57 mg/g. When the mass concentrations of uranium and interfering ions in the solution were both 90 mg/L, the adsorption capacity of imidazole-based functional resin for uranium can reach 44 mg/g, while the adsorption capacity of any single interfering ion (A1³⁺, Ca²⁺, Mg²⁺, Zn²⁺, Mn²⁺, K⁺, Na⁺) is less than 5.4 mg/g. Furthermore, 0.5 mol/L HNO₃ is used as desorption, the desorption rate is 99.83%.When the imidazole-based functional resin is used to adsorb the actual uranium-containing acid waste liquid from a mine, the adsorption capacity of uranium is 40.2 mg/g, which is superior to that of common 201×7 anion exchange resin.

Solvent extraction is one of the main methods for rare earth separation and purification, but emulsification often occurs in industrial production due to improper control of process conditions. In order to solve the problem, the extraction of rare earth with the surfactant Span 80 as the regulator, P507 as the extractant and kerosene as the diluent was studied. The effects of aqueous pH, stirring speed and water-oil phase ratio on the extraction rate of Er³⁺ and the mass concentration of oil in the raffinate were investigated, and the process parameters were optimized by response surface method. The optimization results show that under the optimal conditions of aqueous pH=3.5, stirring speed of 130 r/min and water-oil phase ratio of 4∶1 for 5 min, the extraction rate of Er³⁺ can reach 95.42%, and the oil concentration in the raffinate is only 1.68 mg/L. The predicted value is in good agreement with the experimental results. The addition of Span 80 can effectively prevent emulsification, and the regulation effect is obvious.

In order to reduce the content of impurities such as Cu, Fe, Zn and reduce the loss of Ni in crude nickel sulfate solution of copper electrolysis by-products, the process of selective precipitation of copper by Na₂S₂O₃—deep extraction of zinc removal iron—evaporation crystallization was studied for deep purification of the solution, and the key process parameters were optimized. The results show that the precipitation rate of Cu can reach 99.89% and the loss rate of Ni is only 1.22% using Na₂S₂O₃ as precipitator under the optimum conditions of Na₂S₂O₃ excess coefficient of 2.0, solution pH of 5.0, reaction temperature of 85 ℃ and reaction time of 2 h. Using P204 as extracant, the extraction rates of Zn and Fe can reach 99.87% and 99.98%, respectively, and the loss rate of Ni is 2.24% under the optimal conditions of pH=3.0, P204 volume fraction of 25%, saponification rate of 50%, V_O/V_A=1.5/1, extraction temperature of 25 ℃ and extraction time of 10 min. Electroplating grade nickel sulfate crystal products are obtained by evaporation and crystallization of the deeply purified nickel sulfate solution. The quality can meet the national standard GB/T 26524—2023 Class Ⅱ indicators, and can be used as high-quality raw materials for electroplating and other industrial uses.

To address the issue of low ion exchange adsorption performance of natural zeolite caused by the presence of impurities, which makes it ineffective in adsorbing ammonia nitrogen in wastewater, the modification of natural zeolite using inorganic acids, inorganic bases, and inorganic salts was studied. The effects of different initial ammonia nitrogen mass concentration, zeolite particle size, zeolite dosage and reaction time on ammonia nitrogen adsorption performance of natural zeolite were investigated. The adsorption effects of zeolite under different modification conditions on ammonia nitrogen were compared. The results indicate that the ammonia nitrogen adsorption rate of natural zeolite gradually decreases with the increase of zeolite particle size and initial ammonia nitrogen mass concentration, and gradually increases with the increase of zeolite dosage and reaction time. The ammonia nitrogen adsorption effect of zeolite modified by sodium chloride is significantly better than that of zeolite modified by inorganic acids and inorganic bases, as well as other inorganic salts. When the sodium chloride concentration is 0.8 mol/L, the ammonia nitrogen adsorption rate can reach 78.0%, which is 1.64 times that of natural zeolite.

The design and optimization of extraction mixing tank is one of the key factors affecting the extraction efficiency of rare earth. The mixing performance of semi-open curved-blade disc-type stirring impeller(semi-open BWY), semi-open straight-blade disc-type stirring impeller(semi-open BPY), closed curved-blade disc-type stirring impeller (closed BWY) and closed straight-blade disc-type stirring impeller(closed BPY) paddle in the mixing tank was studied by experiment and numerical simulation. The negative pressure, power, discharge flow rate and flow field distribution generated by the four types of impellers at different rotational speeds were investigated. Taking closed BPY as an example, the six parameters of blade diameter, blade width, blade arc length, inner ring diameter, suction port diameter of the mixing tank, and the height between the blade and the suction port were analyzed in detail. The correlation equations of negative pressure, power number, turbulent kinetic energy dissipation rate and displacement number were established. The results show that under the same power conditions, reducing the blade diameter, inner ring diameter, suction port diameter, height between the blade and the suction port and blade width, as well as increasing the blade arc length, can enhance the mixing suction capacity, but it can reduce the blade displacement.

In order to accurately simulate the variation process of gold leaching rate, a multistage leaching model was designed, and the reaction rate prediction model based on the Forward Neural Network (FNN) and Radial Basis Function (RBF) was constructed.The validity of the model was verified by numerical simulation and comparative test. The results show that the error between the predicted value and the actual value of the gold leaching rate is between 2.1% and 2.6%, which is effective and accurate.

In the production and processing of NdFeB,more than 30% of rare earth metals will be transferred to the waste, resulting in NdFeB waste can not be effectively used. With the rapid development of new energy automobile industry,the green recycling of NdfeB waste has become a research hotspot in this field. The current research status of hydrometallurgy for recycling NdFeB waste at home and abroad, including acid leaching,precipitation, solvent extraction, alkali decomposition, ionic liquid recovery, hydrolysis and microbial decomposition, are reviewed. At the same time, the technical difficulties facing the current research are pointed out. Finally, the main research direction of NdFeB waste recycling in the future is put forward, which provides valuable reference for the secondary utilization of rare earth resources.

The process of synergistic leaching of lithium from waste lithium iron phosphate (LFP) and lithium cobalt oxide (LCO) battery cathode materials was studied, and the feasibility was analyzed by thermodynamics. The influence of various factors on synergistic leaching was investigated,and the leaching slag was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that LFP and LCO can synergistically leach lithium in an acidic system without adding any oxidant or reducing agent. The leaching rates of Li, Co, Fe and P in the cathode materials of waste batteries are 99.99%, 99.99%, 48.00% and 43.77%, respectively, under the optimal leaching conditions of sulfuric acid concentration of 0.7 mol/L, leaching temperature of 40 ℃, leaching time of 60 min, n(LCO)∶ n(LFP)=0.5 and liquid volume to solid mass ratio of 10 mL/1 g. The method can realize the purpose of recovering valuable metals from complex battery cathode materials under low acid conditions, and has certain popularization and application value.

In the process of recovering rare earth from NdFeB waste and polishing powder waste, there are problems such as large reagent consumption and high processing cost. In view of the above problems, using the reducibility of the iron in the NdFeB waste, a combined process was studied to recover rare earth from two kinds of waste. The results show that when NdFeB waste is dissolved with 6 mol/L hydrochloric acid and oxalic acid 1.2 times the mass of rare earth is added into the acid solution, the iron precipitation rate is 7.87%, and the rare earth precipitation rate can reach 96.51%. Adding 6 mol/L hydrochloric acid to the precipitated liquid is used to reduce and leach rare earth from the polishing powder waste. Under the conditions of solid mass to liquid volume ratio of 3 g/6 mL between the polishing powder waste and the precipitated liquid, the product ratio of hydrochloric acid to the precipitated liquid of 7/6, reaction temperature of 60 ℃, and reaction time of 30 min, the average leaching rate of rare earth in the polishing powder waste can reach 82.41%. The dissolved rare earth is precipitated by oxalic acid and calcined, and the total amount of rare earth oxides obtained is 98.04%. The process can realize the joint recovery of rare earth in the two kinds of waste, reduce the cost of rare earth waste treatment,and has a certain popularization and application value.