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.

Aiming at the difficulty in separating and recovering copper and cobalt from iron-cobalt-copper alloys, a process was proposed to leach iron and cobalt from the alloy with low-concentration sulfuric acid, separate copper, and then separate iron and cobalt by oxygen pressure hydrolysis to prepare iron oxide. The effects of various factors on the low-concentration acid leaching and the separation of iron by oxygen pressure hydrolysis were investigated. The results show that the leaching rates of iron and cobalt are 98.57% and 99.21%, respectively, and the copper leaching rate is only 0.3% after 4 times of leaching, under the conditions of sulfuric acid concentration of 30 g/L and liquid volume to solid mass ratio of 10∶1. Under the conditions of oxygen partial pressure of 0.4 MPa, reaction temperature of 180 ℃, stirring speed of 400 r/min and reaction time of 120 min, the hydrol ysate is mixture of FeOOH and Fe₂O₃, the iron content is more than 58%, the iron immersion rate was about 92%, the cobalt recovery rate is more than 99.5%, and the sulfuric acid yield is 96.41%. The method realizes the separation of iron, cobalt and copper in iron, cobalt and copper alloys, and recycles the sulfuric acid produced during the hydrolysis process, which can offset the sulfuric acid consumption in the leaching process and greatly increase the cobalt concentration in the solution. The results of this study have important reference value for the wet separation of iron-based alloys containing valuable metals such as copper and cobalt.

To address the issues of high energy consumption, low efficiency, difficult recovery and easy secondary pollution in the pyrometallurgical recovery of lithium from solid waste, the enhanced leaching of lithium from discarded lithium aluminum silicate (Li₂O-Al₂O₃-SiO₂, LAS) glass-ceramics samples using a mixed acid of HF/H₂SO₄ as the leaching agent was studied. The effects of liquid volume to solid mass ratio, sulfuric acid mass concentration, leaching temperature, leaching time, stirring speed and raw material particle size on the leaching rate of lithium were investigated, as well as the effects of liquid volume to solid mass ratio and leaching temperature on the leaching rates of aluminum and silicon. The kinetics of lithium leaching was also explored. The results show that under the optimal conditions of m(sample)∶ V(HF)∶V(H₂SO₄)=1∶2.5∶2, particle size of -0.074 mm, sulfuric acid mass concentration of 900 g/L, leaching temperature of 60 ℃, leaching time of 120 min, and stirring speed of 200 r/min, the leaching rate of lithium can approach 99%. Compared with other influencing factors HF volume to sample mass ratio and leaching temperature have a greater impact on the leaching rate of lithium. In contrast, the HF volume to sample mass ratio and leaching temperature have a greater effect on the leaching of aluminum than that of silicon. The leaching of lithium conforms to the unreacted core shrinkage model, with an apparent activation energy E_a of 39.53 kJ/mol, and the leaching rate of lithium is controlled by the chemical reaction-internal diffusion mixed control. The research results can provide theoretical guidance for the recovery and reuse of valuable elements from discarded LAS glass-ceramics.

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.

To address the issues of low conversion rate of aromatic amine monomers and high consumption of oxidants in polymerization reactions, the synthesis of polymeric Schiff base nanoparticles using m-phenylenediamine and glutaraldehyde as monomers through aldol-amino condensation reaction and their application in the adsorption and removal of Cu(Ⅱ) from wastewater were investigated. The morphology and structure of the products were characterized, and the thermal stability, acid stability, and adsorption mechanism of the material for Cu(Ⅱ) in wastewater were analyzed. The results show that the amino and aldehyde groups underwent nucleophilic addition to form a Schiff base structure, and the products are spherical nanoparticles with diameters ranging from 100 to 400 nm. The $\mathrm{C}=\mathrm{N}$ structure of the polymeric Schiff base has good thermal stability and acid stability, and the adsorption process of Cu(Ⅱ) conforms to the characteristics of the Langmuir isothermal adsorption model and the pseudo-second-order kinetic model. Under optimized conditions, the equilibrium adsorption capacity of the polymeric Schiff base for Cu(Ⅱ) is 116.30 mg/g, which is superior to that of common biochar, magnetic iron, and other polymer materials. The adsorption mechanism of the polymeric Schiff base for Cu(Ⅱ) is mainly electrostatic interaction and show strong coordination ability.

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.

Aiming at a high iron and low grade laterite nickel ore in Indonesia, the effects of leaching conditions on the leaching of main valuable metals in the raw ore were analyzed, and the change of iron grade in the leaching residue was studied using ferrous sulfate as leaching agent. The results show that under the conditions of oxygen partial pressure of 0.4 MPa, dosage of ferrous sulfate of 280 kg/t, liquid volume to solid mass ratio of 3/1, stirring speed of 300 r/min,raw ore size of 140 ~ 200 μm and temperature of 240 ℃ for 45 min, the leaching rates of nickel and cobalt can reach 98.2% and 98.1%, respectively. The iron average grade of leaching slag can be increased to 55.8%, which is about 10% higher than that of raw ore. In the process of pressure leaching by oxygen, ferrous sulfate can be oxidized and decomposed into sulfuric acid and hematite, which is conducive to further improv the iron grade of the leaching residue.

The effects of the changes of speed (N), distance (C₁) from the bottom and pitch (C₂) of the double-layer baffle three-arc blade composite paddle on the flow field in the stirring tank using particle image velocimetry (PIV) were studied. The flow field characteristics of the double-layer baffle three-arc blade propeller and the double-layer baffle-free three-arc blade propeller were simulated and compared. The results show that when the rotation speed N=110 r/min, the velocity distribution of the flow field in the kettle is relatively uniform, and the high-speed zone in the kettle is concentrated near the propellers. When C₂=0.27h(h is the liquid level height of the stirred tank), the connection flow between the propellers is stable, and the overall mixing capacity in the kettle is significantly enhanced. When C₁=0.29h, the area of the low-velocity zone in the kettle is greatly reduced. The baffle of the double-layer baffle three-arc blade propeller limits its radial pushing capacity, but the axial pushing capacity is significantly enhanced. The research results can provide a reference for the application of double-layer baffle three-arc blade propeller in practical industry.

Aiming at the problems of low pre-treatment efficiency and significant mass spectrometry interference in the determination of rare earth elements in coal-related samples, a method for the determination of rare earth elements in coal and fly ash samples by high-temperature and high-pressure microwave digestion-ICP-MS in a mixed acid system of HNO₃-HF-HClO₄-H₂SO₄ was established. The effects of pre-treatment methods, sample weight, digestion system and mass spectrometry interference on the determination results were investigated. The results show that the linear correlation coefficients of the calibration curves are all greater than 0.999 6, the detection limits are 0.003 7~0.042 μg/g, the relative standard deviations (RSD, n=11) of the determination results of each element are all within 5.85%, the recoveries of standard addition are 95.0%~107.2%, and the relative errors are all less than 6.95%. The method has high accuracy and good stability, which greatly improves the determination efficiency.

In view of the secondary vanadium resources in high-sulfur petroleum coke gasification ash, vanadium was preenriched by oxidation roasting and then recovered by leaching with sulfuric acid. The leaching rule of vanadium from ash of oxidation roasting was investigated, the optimal leaching conditions were determined, and the leaching kinetics was discussed. The results show that under the conditions of temperature of 90 ℃, sulfuric acid concentration of 30%, liquid volume to solid mass ratio of 8∶2 and reaction time of 3 h, vanadium leaching rate in ash can reach more than 72.5% and vanadium mass fraction in acid leaching residue is 1.91%. In the test temperature range, the vanadium leaching rate conforms to the mixing control of the unreacted shrinkage core model,and the apparent reaction activation energy is 22.97 kJ/mol.