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.

The harmless treatment and resource utilization of spent cathode carbon from the overhaul slag of aluminum electrolytic cells is the bottleneck for achieving green and sustainable development in the electrolytic aluminum industry. The migration patterns of toxic components and toxic elements in spent cathode carbon for aluminum electrolysis are introduced. The technical principle, research status, advantages and disadvantages of high temperature fire method, liquid-phase leaching method and collaborative treatment method are summarized, and the future development trend is prospected.

Zinc and cadmium were recovered by acid leaching—vulcanization impurity removal method from dust of slide blowing—fuming process for treating jarosites, and copper was selectively removed from the leaching solution by sulfide precipitation. Subsequently, the obtained purified solution will be used to prepare Cd-doped ZnS composites. Based on the thermodynamic analysis, the influencing factors and kinetics of zinc leaching rate in sulfuric acid system were investigated, and the influence of various parameters on sulfidation was elucidated through orthogonal tests. The results show that the zinc in dust mainly exists in the form of zinc oxide, the leaching reaction follows a mixed control model with a 73.70 kJ/mol activation energy. Zinc leaching rate can reach 98. 99% under the optimum conditions. The copper removal rate can reach 95.97% under 3.2 theoretical times of Na₂S addition at pH of 2.0, with high retaining rate of Zn and Cd, achieving effectively selective separation of copper from zinc and cadmium.

Aluminum was extracted from fly ash by (NH₄)₂SO₄ roasting activation—sulfuric acid leaching method. The effects of liquid volume/solid mass ratio, reaction temperature, reaction time and sulfuric acid concentration on the leaching rate of aluminum were investigated. The kinetics of acid leaching process of clinker was studied. The results show that the leaching rate of aluminum is 84.64% under the conditions of liquid volume/solid mass ratio of 8/1, reaction temperature of 90 ℃, reaction time of 120 min and sulfuric acid concentration of 20%. The leaching kinetic formula is $1-{(1-x)}^{\frac{1}{3}}$=6. 033 93${e}^{\frac{-22.045 4}{RT}}$t, and the reaction activation energy is 22.045 4 kJ/mol.