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.

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%.

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.

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.

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.

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.

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.

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.

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.

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).