Recovering and reusing ruthenium from platinum group metal waste has great influence on sustainable development, resource conservation and environmental protection. Ruthenium waste generally includes ruthenium-containing waste catalysts, ruthenium-containing alloy materials, ruthenium-containing nuclear waste and other ruthenium-containing waste. The comprehensive recovery and treatment methods of different ruthenium wastes are summarized. The processes of transforming soluble salts by oxidative distillation, melting-reduction-oxidation, melting-oxidation-distillation, microwave leaching-cloud point extraction, distillation-melting-reduction, melting-reduction-oxidation, ion exchange, oxidation volatilization, electrolysis, biosorption and physical adsorption are introduced respectively. The advantages and disadvantages of existing ruthenium waste recovery technologies are summarized. And the development direction of ruthenium waste recovery technology in the future is prospected.

Leaching of vanadium from stone coal vanadium ore by blank roasting—acid leaching process was studied. The effects of grinding fineness, roasting time, roasting temperature, sulfuric acid addition dosage, leaching aid CaF₂ addition dosage, leaching temperature, leaching time and liquid volume to solid mass ratio on vanadium leaching rate were investigated. The results show that the optimum blank roasting conditions are grinding fineness 70% of -74 μm, roasting temperature of 775 ℃ and roasting time of 5 h. The optimum acid leaching conditions are sulfuric acid addition dosage of 10%, leaching aid CaF₂ addition dosage of 3%, liquid volume to solid mass ratio of 1.5∶1, leaching temperature of 25 ℃ and leaching time of 1.5 h. Under suitable conditions vanadium leaching rate can reach 81.5%.

In order to develop Xiangshan uranium-rare earth associated ore economically and effectively, a novel strain of Microbacterium sp. 6-1 with specific uranium recognition capability was utilized to conduct the bioleaching experiment on Xiangshan uranium-rare earth associated ore. The results show that a novel strain of Microbacterium sp. 6-1 can be directionally attached to the surface of uranium-containing minerals and efficiently leach uranium elements and associated rare earth resources. Around 81% uranium and 62% rare earth elements can be leached from the uranium-rare earth associated ore within 30 d, with a further enrichment of heavy rare earth elements in the leachate. The research results have important reference significance for the comprehensive development of uranium-rare earth associated mineral resources.

Aiming at the comprehensive utilization of niobium minerals in Bayan Obo tailings, the optimum parameters of niobium leaching process were determined by using HF as leaching agent, and the leaching kinetics was studied. The results show that the leaching rate of niobium-containing minerals can reach 90.91% under the conditions of reaction temperature of 90 ℃, liquid volume to solid mass ratio of 7/1, HF concentration of 20 mol/L, reaction time of 2 h and stirring rate of 300 r/min. The leaching process of niobium is consistent with the nuclear shrinkage model, and the leaching process is controlled by chemical reaction and diffusion mixture, and the apparent activation energy of the leaching reaction is 35.459 kJ/mol. This method can effectively extract niobium from tailings and is beneficial to subsequent separation and purification.

In the process of producing ammonium molybdate by roasting and ammonia leaching, the leaching rule of potassium in ammonia leaching process of molybdenum calcine was studied by ICP, XPS, SEM, etc., and the change of occurrence form of potassium in ammonia leaching process was investigated by MLA and Factsage thermodynamic software. The kinetic law of potassium release was investigated by using the unreacted kernel model, parabolic diffusion equation, double constant equation, Elovich equation and first-order kinetic equation. The results show that the leaching of potassium in the ammonia leaching process of washed molybdenum calcination can be divided into two stages:Preleaching stage is the leaching process of ionic potassium, which mainly occurred the ion exchange reaction of KCl and K₂SiF₆, and the leaching activation energy is 4.79 kJ/mol. The Elovich model is the best fit for this stage. Late leaching stage is mainly the leaching process of potassium from mineral potassium, the leaching activation energy is 34.55 kJ/mol, and the optimal kinetic model is a double constant model. At the late stage of leaching, the potassium release rate is slow, and the potassium release ability of the four potassium-containing minerals is from weak to strong in the order of illite<barium ferromica<mica<orthoclase.

The leaching of magnesium from lightly fired powders obtained from low temperature calcination of magnesite by hydrochloric acid acidification was studied. The effects of addition method of hydrochloric acid, concentration of hydrochloric acid, liquid volume/solid mass ratio, external force way and reaction time on magnesium leaching rate were investigated. The leaching kinetics of lightly fired powders under ultrasonic condition was analyzed by using shrinkage core model. And the particle size distribution, mineral composition and mineral distribution characteristics of leaching residue were further analyzed. The results show that under the conditions of slowly adding hydrochloric acid, hydrochloric acid concentration of 14.8%, liquid volume/solid mass ratio of 9.8/1, stirring speed of 400 r/min and leaching time of 12.5 min, the leaching rate of magnesium can reach 70.48%. Using ultrasound can cause hard agglomeration to produce cracks or disintegration, which is beneficial to solid-liquid mass transfer, and the magnesium leaching rate is increased to 90.56%. The leaching process of lightly fired powders conforms to the mixed control model of surface chemical reaction and product layer diffusion. The ratio of magnesium to oxygen in the hard agglomeration is 1.33, the edge is 1.65, and there is a large amount of unreacted magnesium in the hard agglomeration. The particle size of the leaching slag is reduced from 42.61 μm to 24.39 μm by ultrasonic action. The ultrasonic bubble vibration force and the shock wave formed by the cavitation collapse can effectively prevent the formation of hard agglomeration or make the hard agglomeration re-disaggregate.

A set of aluminum dross hydrolysis hydrogen production equipment was experimentally designed and installed. The effects of reaction temperature, liquid volume to solid mass ratio, stirring speed, and aluminum dross particle size on the aluminum dross hydrolysis hydrogen production process were studied, and the kinetics of the aluminum dross hydrolysis hydrogen production process were explored. The results show that the optimal process conditions for aluminum dross hydrolysis hydrogen production are reaction temperature of 85 ℃, liquid volume to solid mass ratio of 10 mL/1 g, and stirring speed of 130 r/min, aluminum dross particle size of >80 mesh. The main phases of the hydrolysis residue obtained under optimal conditions are MgAl₂O₄, Al(OH)₃ and Al₂O₃. The hydrogen production process from aluminum dross hydrolysis is controlled by chemical reactions, with a chemical apparent activation energy of 67.01 kJ/mol. The leaching process follows the Avrami-Erofeyev model. The experimental results can provide certain technical references for the design of aluminum dross hydrolysis hydrogen production process.

Magnetic mesoporous carbon(MMC) and hydroxyapatite(HAP) composite materials with different mass ratios were prepared by co-precipitation method(MMC@HAP-x x=1, 4, and 6), and used for the removal of radioactive U(Ⅵ) in aqueous solution. The structure, functional groups and surface potential of the MMC, HAP and MMC@HAP-x were characterized by XRD, FT-IR, Zeta. The kinetics, thermodynamics, and the mechanism of MMC@HAP-x adsorption of U(Ⅳ) by the aforementioned materials were systematically studied. The results show that the optimal pH of MMC@HAP-x for U(Ⅵ) is 4.0, and the time required to reach adsorption equilibrium is less than 10 min. The theoretical saturated adsorption capacity of MMC@HAP-6 is 1 164.62 mg/g, and the adsorption process is a spontaneous chemisorption process. The fixation of U(Ⅵ) in MMC@HAP-x is due to the interaction between HAP and $\mathrm{UO}_{2}^{2+}$ to form Ca(UO₂)₂(PO₄)₂·3H₂O. MMC@HAP-6 is a fast uranium adsorbent with the potential to be used for the removal of uranium from radioactive wastewater.

The adsorption—resolution process of H₂TiO₃ lithium sieves for lithium extraction from salt lake brine was investigated. The crystal shape and morphology of the screen before and after adsorption were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the surface of H₂TiO₃ lithium ion screen has good particle dispersion, loose pores and stable crystal structure after granulation, and the structure does not change significantly after recycling. In the continuous ion exchange system, the 30 columns are divided into 6∶1∶2∶1 according to the four steps of adsorption—washing material—desorption—acid washing, under the optimal conditions of the adsorption feed flow rate of 12 BV/h, the adsorption time of 3 h, the washing flow rate of 1 BV/h, the rinsing time of 30 min, the hydrochloric acid in the analytical process of 0.1 mol/L, analytical temperature of 30~40 ℃, the cyclic analytical time of 1 h, the acid washing flow rate of 8 BV/h, the washing rate of 30 min, the continuous operation of 30 cycles, the adsorption performance is stable, the adsorption capacity is about 6.67 mg/g, the adsorption rate is about 80%, and the Li-rich analytical liquid Li⁺ mass concentration is about 1.2 g/L, ρ(Li⁺)/ρ(Na⁺) is about 1. The method has a certain value of industrial popularization and application.

Polyaniline (PANI) coated iron tetroxide was used to prepare of Fe₃O₄@PANI magnetic adsorption material for the adsorption of iodine in water. The morphology and properties of the composite before and after adsorption were characterized by SEM, TEM, FT-IR, XRD, VSM, XPS and Raman, and the adsorption mechanism of the composite was explored. The effects of adsorption time, iodine solution concentration, adsorption temperature and regeneration on the adsorption properties were also investigated. The results show that iodine is bound to benzene ring, quinone ring and nitrogen atom of quinone ring structure unit of polyaniline when coated with ferric tetroxide adsorbed I₂. The adsorption process of I₂ by Fe₃O₄@PANI is endothermic and spontaneous, which accords with the quasi-second-order kinetic model and the Langmuir isothermal adsorption model. At 303.15 K, the theoretical maximum adsorption capacity is 1 777.13 mg/g. After the adsorbent is desorbed with ethanol and recycled for 3 times, the adsorption rate reached 44.22% of the first adsorption rate.

A new process for preparing high-purity copper by electrorefining in a nitric acid system was developed using a 4N copper cathode as raw material. The effects of electrolyte composition on the content of S, Cl, typical positively charged and negatively charged impurities in copper cathodes were investigated. Moreover, the influence of Cu(NO₃)₂·3H₂O raw material purity, electrolyte components(Cu²⁺, HNO₃ and Cl^- mass concentrations), and electrolysis period on copper cathode purity, impurity content, current efficiency, and electrical energy consumption was analyzed. The results show that the optimum process conditions are to prepare the electrolyte using 99% purity of Cu(NO₃)₂·3H₂O, with Cu²⁺ mass concentration of 50 g/L, HNO₃ mass concentration of 31.5 g/L, Cl^- mass concentration of 0.1 g/L, and electrolysis period of 72~120 h. Under the optimal conditions, high-purity copper cathode with purity up to 6N5 and main control impurity elements can meet the high purity cathode copper required by HPCu-6N in the national standard (GB/T 26017—2020).

In the process of cobalt extraction from Congo (Kinshasa) copper-cobalt polymetallic symbiotic ore, active magnesium oxide was selected to precipitate cobalt in cobalt containing solution and to prepare crude cobalt hydroxide. The kinetics of hydroxide precipitation in solution was discussed. The effects of particle size of magnesium oxide, the amount and method of adding magnesium oxide, reaction time and temperature on precipitation of iron, cobalt and manganese were investigated. The results show that the impurity iron in the simulated cobalt solution can be quickly removed by adding 30% hydrogen peroxide. Active magnesium oxide with particle size less than 45 μm is added to the simulated cobalt containing solution according to the addition amount of 0.68/1 and multiple additions by reaction at room temperature for 6 h, and the obtained primary precipitation can meet the requirements of industry standards for gradeⅠ and secondary precipitation can meet the requirements of gradeⅢ. The process has the advantages of low cost and high practicability, and can effectively improve the efficiency of magnesium oxide cobalt deposition.

In order to solve the problem of high impurity in the preparation of beryllium hydroxide by BeSO₄ solution in the process of uranium extraction from high fluoride uranium-beryllium ore, the precipitation of crude beryllium hydroxide with high Fe and Al impurities was studied by resolubility hydrolysis method. The effects of precipitation method of crude Be(OH)₂, the amount of NaOH and resolubility temperature on the resolubility of crude Be(OH)₂ were investigated. The results show that Be and $\mathrm{SO}_{4}^{2-}$ can be separated efficiently by resolubility hydrolysis method, and the content of Fe and Al in the product can be greatly reduced. The high purity BeO products can be prepared by roasting the obtained high purity Be(OH)₂ which meets the industrial standard.

The removal of aluminum nitride is one of the keys processes of the harmless treatment of secondary aluminum ash. The removal of aluminum nitride from secondary aluminum ash in calcium oxide-glucose hydrolysis system was studied. The effects of calcium oxide addition amount, glucose addition amount, hydrolysis temperature, hydrolysis time and liquid volume to solid mass ratio on the removal rate of aluminum nitride were examined. The mechanism of aluminum nitride hydrolysis removal promoted by additives was investigated. The results show that under the optimum hydrolysis conditions of hydrolysis temperature of 90 ℃, hydrolysis time of 2 h, liquid volume to solid mass ratio of 10 mL/1 g, calcium oxide addition amount of 10%, glucose addition amount of 0.75%, the removal rate of aluminum nitride reaches 95.42%. Through analysis and characterization, it is determined that in the calcium oxide-glucose hydrolysis system, glucose acts as a retarder, which can inhibit the formation of calcium aluminate coating layer on the surface of aluminum nitride particles, make the hydrolysis of aluminum nitride thoroughly, and improve its removal rate.

After contaminated acid in zinc hydrometallurgy was vulcanized, neutralized by zinc calcine and calcium carbonate, arsenic and fluorine can be removed from the solution, and the amount of gypsum residue decreased. But the solution can not return to zinc hydrometallurgy system because it has a high chlorine content. The chlorine in the solution was removed with copper slag. The results show that under the conditions of hydrogen peroxide addition of 2.3 mL/L, copper slag coefficient of 6.8, initial acid mass concentration of 15 g/L, temperature of 35 ℃ and reaction time of 2 h, the chlorine removal rate is 72.58% and the chlorine mass concentration decreases from 0.62 g/L to 0.17 g/L. The copper mass concentration in solution is 2.69 g/L copper, and it can be returned to the zinc hydrometallurgy after subsequen copper removal by zinc powder or iron powder.

Taking the fluorine-containing wastewater generated by a tungsten smelting enterprise as the research object, aiming at the problem that the defiuorination effect of the existing process can not meet the requirements of the national comprehensive sewage discharge standard, three processes of calcium chloride precipitation method, calcium chloride aluminum salt coagulation precipitation method and ion exchange refsin defluorination method were compared and studied. The results show that it is difficult to ensure the standard discharge of wastewater by using calcium chloride precipitation method alone. Both calcium chloride aluminum salt coagulation precipitation method and resin defluorination method can reduce F^-mass concentration in wastewater from 58.45 mg/L to below 10 mg/L and the discharge standard can be achieved. In contrast, the resin has the best fluoride removal effect and the defluorination rate of 99.64%. It can be used in combination with chemical precipitation as a combination of deep defluoriation process.

The electric submersible pump (ESP) is the main equipment for the in-situ leaching uranium industry in China, effectively increasing the production of leaching fluid. However, few studies on the internal flow field subject to rotating-stationary-parts interactions are available in literature. With the internal structure of impeller-guide vane as the research object, CFD method was applied to carry out unsteady analysis on the flow characteristics of the medium, and the variation mechanism of pressure pulsation inside the impeller and the outlet section of the impeller was studied. Moreover, the transient flow field data were used to analyze the pressure flow field in the section of the impeller through the action mode decomposition (DMD) and pressure flow field reconstruction. The periodic variation mechanism of pressure pulsation caused by static and dynamic interference and the influence of distance between static and dynamic components on the intensity of static and dynamic interference are revealed. The results indicate that the frequency values of the blades are basically consistent with those of the Fast Fourier Transform (FFT). These findings offer valuable theoretical underpinnings for mitigating undesirable pump vibrations induced by pressure pulsations, optimizing ESP hydraulic component parameters, and ultimately improving system efficiency.