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.

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%.

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.

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.

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).

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.

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.

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.