The composition, preparation methods, and mass transfer mechanisms of ELM (emulsion liquid membrane), SLM (supported liquid membrane), and PIM (polymeric inclusion membrane), and the research progress of these three types of membranes in hydrometallurgy in recent 5 years are reviewed. Additionally, the advantages and disadvantages of the three membranes in hydrometallurgy were summarized, and the solution to the problems such as ELM films exhibited instability and difficulties with emulsion breaking, SLM membranes tended to be unstable with the membrane phase is lost to the water phase and PIM demonstrated lower mass transfer efficiency requiring longer time to reach equilibrium are proposed. Finally, the future development direction for the three membranes in the field of hydrometallurgy are prospected, providing a crucial foundation for further promoting the application of membrane extraction technology in hydrometallurgy and expediting the industrial production of membrane extraction technology.

A large amount of waste electrolysis is produced in the zinc electrolysis process. Waste electrolyte is acidic and contains many metal ions, such as direct discharge of serious pollution to the environment. Using waste electrolyte and concentrated sulfuric acid as leaching medium, the comprehensive recovery of gold, silver and zinc from wet zinc smelting slag by acid leaching and flotation process was studied. Taking the leaching slag(old slag) produced by conventional leaching process as the main object of study, the effects of pulp stirring speed, waste electrolyte dosage, sulfuric acid addition amount and acid leaching temperature on the flotation indexes of gold and silver were investigated. The results show that using the acid leaching and flotation process, the closed-circuit test of old slag finally obtains the concentrate with gold grade of 10.16 g/t, gold recovery of 78.63%, silver grade of 1 039.64 g/t, silver recovery of 74.72%, zinc grade of 40.64%, zinc recovery of 21.86%, the recovery of zinc in acid leaching solution is 60.15%. The validation test is carried out using the leaching slag (new slag) produced by hot acid leaching process and the fresh slag pulp produced by the leaching process, and a good closed-circuit test index is obtained. The method can realize the recycling of the waste electrolyte and make the valuable metals in the slag be recovered efficiently and comprehensively.

In order to realize resource utilization of solid waste and effective control of nitrogen oxides in low-temperature flue gas, the preparation of high efficiency manganese and zeolite NH₃-SCR catalysts from low-grade manganese tailings was studied. The initial concentration of nitric acid, liquid volume to solid mass ratio, leaching temperature and leaching time were optimized by single factor method and response surface method. The catalytic performance of the catalyst prepared by the leaching products was tested. The results show that under the optimum conditions, the manganese leaching rate reaches 98%. The catalyst has excellent denitrification performance in the temperature range of 200~350 ℃, and the conversion rate of NO reaches 98%. By optimizing the leaching process parameters, the high efficiency utilization of low-grade manganese tailings can be realized, and the catalyst with remarkable denitrification effect can be prepared, which has broad prospects in industrial application.

In order to maximize the extraction efficiency of zinc and germanium from high-silicon and low-germanium zinc oxide dust(ZOD), the ultrasonic enhanced leaching process assisted by sodium dodecyl sulfate (C₁₂H₂₅SO₃Na) was constructed and optimized by response surface method(RSM),and the accurate prediction model of zinc and germanium leaching rate was established. The results show that on the basis of single factor test, the optimal leaching conditions determined by RSM are leaching temperature of 70 ℃, liquid volume to solid mass ratio of 8 mL/1 g and initial acid mass concentration of 160 g/L. The leaching rates of zinc and germanium can reach 96.94% and 85.41%, respectively. C₁₂H₂₅SO₃Na plays a key role as a silica gel inhibitor in the leaching process, effectively preventing the polymerization of silicon ions into silica gel, and this effect is more significant under the combined ultrasonic treatment, reflecting the synergistic benefit between temperature, ultrasound and C₁₂H₂₅SO₃Na.The research results provide an efficient recovery strategy for the resource utilization of high-silicon and low-germanium zinc oxide dust, and provide an important technical reference for the recovery of other high silicon waste.

In view of the problems of low impurity removal rate and low grade of germanium concentrate in the washing process of tannin germanium residue, the As, Zn and Fe impurities in tannin germanium residue were effectively removed by washing with dilute sulfuric acid solution. The effects of sulfuric acid mass concentration, washing temperature and washing time, liquid volume to solid mass ratio on the removal rate of As, Zn and Fe impurities and Ge loss rate were investigated. The results show that under the conditions of sulfuric acid mass concentration of 60 g/L, liquid volume to solid mass ratio of 5 mL/1 g, washing temperature of 60 ℃,first washing time of 120 min, second washing and third washing time of 60 min, the cumulative removal rates of As, Zn and Fe can reach over 88%, 97% and 95%, respectively. Ge cumulative loss rate is less than 1.50%. The Ge and As grades of germanium concentrate prepared by three-stage countercurrent pickling and oxidation roasting process are 34.45% and 0.54%, respectively, which meet the tertiary standard of germanium concentrate.

The cathode material of spent ternary lithium-ion battery is rich in valuable metals such as Li, Ni, Co and Mn, and efficient separation and recovery of these metals is crucial for environmental protection. The principles, conditions and effects of chemical precipitation, solvent extraction and electrochemical deposition for the separation of dissolved Li, Ni, Co and Mn are evaluated and analyzed. According to the failure mechanism of NCM cathode material, the development status, advantages and disadvantages of direct regeneration strategy of solid-state sintering, hydrothermal method and lithium based eutectic molten salt method, and indirect regeneration strategy of coprecipitation method, sol-gel method and electrochemical method are systematically reviewed. The challenges faced in the separation of valuable metals such as lithium, nickel, cobalt and manganese and the recycling of electrode materials are summarized, and the improvement direction is put forward to provide important guidance for the efficient recycling of valuable metals in the cathode materials of spent ternary lithium-ion batteries.

The synthesis of a polyethylene imine-functionalized biochar aerogels (LSBC-CTS/PEI) using lotus seed powder, chitosan and polyethylene imine as materials, and used for adsorption of U(Ⅵ) in wastewater was studied. The results show that LSBC-CTS/PEI exhibit a looser structure with interconnections, and contains very rich amine-based functional groups, which can provide more adsorption sites for U(Ⅵ) coordination. The selective adsorption of U(Ⅵ) by LSBC-CTS/PEI is greatly affected by pH. The adsorption is mainly composed of single-layer chemisorption, which belongs to a spontaneous endothermic process, and is more suitable for description by quasi-second-order kinetics and Langmuir isothermal adsorption model. The selectivity of LSBC-CTS/PEI to uranium is 84.91%, and the maximum adsorption capacity is 533.89 mg/g. The adsorption material has high adsorption capacity of uranium, good selectivity, and convenient separation of solid and liquid, so it has the certain value of application.

The microwave-ultrasonic assisted leaching of V and Mo in spent petrochemical catalyst with sodium hydroxide was studied. The effects of various factors on the leaching were investigated. The kinetics of the leaching process was analyzed. The results show that under the conditions of no mechanical agitation, solid mass to liquid volume ratio of 0.20 g/1 mL, leaching temperature of 90 ℃, sodium hydroxide concentration of 2.0 mol/L, microwave power of 600 W, ultrasonic power of 300 W, and leaching time of 30 min, the leaching rates of V and Mo in the waste catalyst can reach 95.66% and 96.28%, respectively. The apparent activation energy of microwave-ultrasonic assisted leaching is 18.80 kJ/mol, which is significantly lower than that of atmospheric leaching. This is related to the fracture of chemical bonds caused by the high temperature and high pressure, which is achieved by the selective heating characteristics of microwave and the cavitation of ultrasonic.

As a new heating and material processing technology, microwave technology has been paid more and more attention in the field of rare earth application. This paper introduces the mechanism and characteristics of microwave heating, summarizes the research and application status of microwave heating technology in rare earth hydrometallurgy and rare earth material preparation, and points out the main problems and the development directions of in the future.

Uranium is a widely distributed radioactive heavy metal on Earth, and its geochemical cycling is regulated by various microorganisms. This paper critically reviews the roles of microbes in the transformation of uranium species, including reductive immobilization, non-reductive immobilization, oxidative migration, and non-oxidative migration. By exploring the interaction between uranium and microorganisms in natural environments, a profound understanding of uranium migration, transformation, and enrichment mechanisms is achieved, thereby providing guiding insights for the exploration of uranium resources, the safe disposal of radioactive uranium-containing waste, and the remediation of heavy metal uranium pollution.