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.

Aiming at the high efficiency leaching of W and V in a SCR denitration catalyst, the microwave assisted leaching of W and V in waste SCR catalyst was studied. The results show that under the conditions of microwave power of 600 W, reaction time of 1 h, reaction temperature of 60 ℃, sodium hydroxide concentration of 40% and liquid volume/solid mass ratio of 7.5/1, the leaching rates of W and V in SCR denitration catalyst can reach 89.96% and 96.32%, respectively. After leaching the alkaline leaching residue with 4 mol/L HCl solution for 1 h, TiO₂ with a purity of 98.76% is obtained. Compared with the traditional water bath heating method, microwave heating leaching method can not only improve the leaching rate of tungsten and vanadium on SCR denitrification catalyst, but also greatly shorten the test reaction time, which provides a reliable technical basis for the green effective leaching of W and V in SCR denitrification catalyst.

Dephosphorization slag contains a large amount of valuable components such as CaO, SiO₂, FeO, P₂O₅, etc., and has the potential to be used as soil amendment and fertilizer. To promote utilization of dephosphorization slag in agriculture, it is necessary to understand its dissolution behavior in the organic acid solution. The influence of pH and organic acid type on the dissolution ratios of various valuable elements from dephosphorization slag was investigated. The results show that the main mineral phases in the dephosphorization slag are RO phase, CaFeSiO₄ matrix phase, and C₂S-C₃P solid solution. Ca and Si elements in the slag are mainly distributed in the C₂S-C₃P solid solution and CaFeSiO₄ matrix phase, while the P element is enriched in the C₂S-C₃P solid solution. Fe element is mainly distributed in the RO phase. As the pH value decreased, the dissolution of slag is significantly promoted, and most of the dephosphorization slag can be dissolved in the citric acid solution. At pH=5, the dissolution ratios of Ca, Si, Mg elements are about 90%, and the P dissolution ratio is 68.84%, achieving the dissolution of valuable elements.

The mineral composition and valence state composition of vanadium clinker in vanadium slag and salt-free roasting stage at different temperature nodes were studied by photoelectron spectroscopy and mineral analyzer. The results show that the contents of vanadium spinel, ferroolivine and calciferite decrease with the increase of roasting temperature, while the contents of iron oxide, ferrotitanite and manganese vanadate increase with the increase of roasting temperature. With the increase of roasting temperature, the oxidation of vanadium slag from V³⁺ to V⁴⁺ is gradually transformed into the internal oxidation of V³⁺ to V⁴⁺ and V⁴⁺ to V⁵⁺. The valence state of vanadium in vanadium spinel is V³⁺ and the valence state of vanadium in oxidation state is V⁴⁺. The mineral analysis results of vanadium slag and clinker are in good agreement with the valence analysis results of vanadium element.

In order to recover Ni from acid leaching solution of waste oil refining catalyst, HBL110 was used as extractant to extract nickel directly and selectively. The saponification rate of extractant, extractant concentration and extraction equilibrium time were optimized, the extraction and de extraction stages were confirmed, and the multi-stage countercurrent series extraction simulation test and the continuous running of the on-line process were carried out. The results show that under the conditions of saponification rate of 40%, HBL110 concentration of 25% and extraction time of 10 min, the mass concentration of nickel in the raffinate is less than 30 mg/L, the extraction efficiency of nickel is more than 98%, and the extraction rate of Al and Fe is less than 3%. The three stage countercurrent extraction of nickel supported organic phase with 75 g/L sulfuric acid can achieve 100% back extraction of nickel supported organic phase. The on-line extraction process of the acid leaching solution of the waste catalyst is run continuously for 5 days, the nickel concentration in the raffinate is stable at 5 mg/L, and the extraction efficiency of nickel can reach 99%. The concentration of nickel in the back extraction solution is stable at 8 g/L, and the back extraction rate of nickel is 100%. The organic phase can be effectively recycled.

Aiming at leaching solution of indium residue produced by zinc hydrometallurgy, rotating disk extraction tower was used to separate indium and iron from the solution. The extraction effects of indium and iron ions in the solution, the extraction sequence of metal ions, the separation effect and emulsification of light and heavy phases was studied. The influences of the rotating disk rotating speed, feed flow rate, concentration of P204, solution acidity, reaction temperature and the phase ratio on separation effects were examined. The results show that under the optimal conditions of reaction temperature of 25 ℃, heavy phase volume flow rate of 7.8 L/h, P204 concentration of 20%, rotating disk rotating speed of 360 r/min, initial acidity of 60 g/L, V_O/V_A phase ratio of 1/1, the extraction rate of indium can reach 75%, the extraction rate of impurity element iron is less than 5%. The light and heavy phases are basically completely separated, and there is no emulsification. The result of extraction isotherms shows that complete extraction of indium can be achieved by three-stage countercurrent extraction under the condition of V_O/V_A phase ratio of 1/1. The loaded organic phase is pre-washed with dilute sulfuric acid, and then stripping with 5 mol/L hydrochloric acid under the condition of V_O/V_A=1/1. And the extraction rate of indium is more than 98%. After the replacement treatment, the stripping solution can be directly returned to zinc hydrometallurgy, the organic phase can be recycled after scrubbing.

Molybdenum targeted-adsorption material (α-BO/PMMA) was prepared by vacuum infusion of α-benzoxime (α-BO) in porous poly-methacrylate carrier (PMMA-DVB), and its structure was characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis and optical microscopy. The effects of acid type, H⁺ concentration, contact time and $\mathrm{MoO}_{2}^{2+}$ concentration on the adsorption properties of α-BO/PMMA were investigated. The results show that the adsorption capacity of α-BO/PMMA on molybdenum is greatly affected by acidity, and the adsorption capacity is the highest in 0.1 mol/L hydrochloric acid medium, and the maximum adsorption capacity is 29.8 mg/g. The material can effectively separate and extract molybdenum.

Novel carboxyl-functionalized two-dimensional covalent organic frame materials TpBD-3COOH COF was synthesized by a solvothermal method using triacetaldehyde mesitylphenol (Tp), 4, 4-diaminobiphenyl-2, 2-dicarboxylic acid (DBd), and biphenylenediamine (BD) as raw materials, and used for adsorption of Rhodamine B dye wastewater. TpBD-3COOH COF were characterized by XRD, FT-IR and SEM. The results show that the removal of Rhodamine B can reach 95% after 60 min under the conditions of pH=4, TpBD-3COOH COF addition of 8 mg and Rhodamine B mass concentration of 10 mg/L in the wastewater. After five repetitive experiments, the removal rate of Rhodamine B by TpBD-3COOH COF still reaches more than 70%. The adsorption process is consistent with the quasi-second-order kinetic model and the Langmuir adsorption isothermal model.

The preparation of nickel, cobalt and manganese ternary precursors by coprecipitation method was studied. The effects of ammonia concentration, system pH, reaction time and reaction temperature on the properties of the precursors prepared by coprecipitation method were investigated. The results show that under the optimal conditions of ammonia concentration of 1 mol/L, pH=12, reaction temperature of 55 ℃ and reaction temperature of 28 h, the prepared precursor products have good particle size distribution, uniform spheroid shape and dense crystallization. The first discharge capacity of the cathode material after calcination is 169.14 mAh/g and the first efficiency is 88.32% under the charge and discharge system of 2.8~4.4 V and 0.2 C.

Aiming at the difficulty of extracting and separating of high purity single rare earth elements or compounds, a new emulsion liquid film was constructed and used for the extraction and separation of Re(Ⅲ) (La³⁺, Ce³⁺, Pr³⁺, Nd³⁺). The types and concentrations of mobile carriers and surfactants, and the internal water phase in liquid film system were determined by single factor experiment. The results show that the optimal composition of the emulsion liquid membrane system is 6%D2EHPA, 5%T154, 3 mol/L HCl solution, phase ratio R_oi=1.5. The emulsion film constructed in this system has stable phase and excellent extraction effect, and can realize efficient separation of Re(Ⅲ).

Aiming at the problems such as long production cycle, low utilization rate of carbon dioxide and difficult to meet the standard requirements of battery grade lithium carbonate produced by traditional carbonization decomposition method, the preparation of battery grade lithium carbonate by sodium carbonate—shear carbonization—ion exchange—heating decomposition process was studied using low-grade leachite ore as raw material. The results show that the removal rates of calcium, magnesium and manganese are 97.26%, 81.82% and 95.73%, respectively, under the conditions of 30 ℃, liquid volume/solid mass ratio of 25/1, carbon dioxide input rate of 0.5 L/min and shear speed of 6 000 r/min. The shear assisted carbonization method can significantly improve the carbonization reaction rate, shorten the reaction time, save more than 70% of CO₂, and is more conducive to the production of battery grade lithium carbonate. The prepared lithium carbonate can meet the standard of battery grade lithium carbonate.

A gold grade prediction model was proposed by combining improved cloud models with improved RBF neural networks. Qualitative information was quantified using DS evidence theory and cloud models, and then quantum particle swarm optimization algorithm and RBF neural network were used to predict the gold grade in ores. The results indicate that the mean square error of this model is 0.009 2, the maximum error is 0.016 1, and the correlation coefficient is 0.940 2, the model can better preserve the qualitative information characteristics, the prediction effect of gold grade is good.

Aiming at the complexity of existing hydrometallurgical process mechanism and the poor accuracy of existing leaching process fault diagnosis methods, an improved dynamic causal diagram was studied to diagnose hydrometallurgical leaching process faults. The dynamic causal diagram was optimized and improved mainly by binary interval number, and the upper and lower limit of conditional probability were weighted to realize the fault diagnosis of hydrometallurgical leaching process. The results show that the fault diagnosis method is more accurate than the conventional method, and can diagnose the faults of leaching process more accurately.

In order to meet the accuracy and timeliness requirements of natural uranium trade reinspection, the working conditions for determining uranium in imported uranium trioxide by wavelength scattering X-ray fluorescence spectroscopy were optimized. Suitable digestion methods, digestion vessels, digestion time and temperature, mylar film, sample quality for determination, and other sample pre-treatment conditions were selected for optimization. The measuring conditions of X-ray tube voltage and current, spectroscopic crystal, wave crest and background angle(2θ), measure the time were determined. The precision, accuracy and reliability of the method were evaluated. The results show that the linear correlation coefficient of the working curve of the method is 0.999 6, and the relative standard deviation (RSD) is 0.029%~0.056%. The relative error between the measurement results and the recommended value of the reference material is ≤0.027%. Compared with the titration method, the absolute deviation of the method is 0.003%~0.093%, the results are accurate and reliable, and The efficiency is 5 times that of titration. The method can meet the requirements for rapid batch analysis of imported uranium trioxide samples.