A set of aluminum dross hydrolysis hydrogen production equipment was experimentally designed and installed. The effects of reaction temperature, liquid volume to solid mass ratio, stirring speed, and aluminum dross particle size on the aluminum dross hydrolysis hydrogen production process were studied, and the kinetics of the aluminum dross hydrolysis hydrogen production process were explored. The results show that the optimal process conditions for aluminum dross hydrolysis hydrogen production are reaction temperature of 85 ℃, liquid volume to solid mass ratio of 10 mL/1 g, and stirring speed of 130 r/min, aluminum dross particle size of >80 mesh. The main phases of the hydrolysis residue obtained under optimal conditions are MgAl₂O₄, Al(OH)₃ and Al₂O₃. The hydrogen production process from aluminum dross hydrolysis is controlled by chemical reactions, with a chemical apparent activation energy of 67.01 kJ/mol. The leaching process follows the Avrami-Erofeyev model. The experimental results can provide certain technical references for the design of aluminum dross hydrolysis hydrogen production process.

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.

Recovering and reusing ruthenium from platinum group metal waste has great influence on sustainable development, resource conservation and environmental protection. Ruthenium waste generally includes ruthenium-containing waste catalysts, ruthenium-containing alloy materials, ruthenium-containing nuclear waste and other ruthenium-containing waste. The comprehensive recovery and treatment methods of different ruthenium wastes are summarized. The processes of transforming soluble salts by oxidative distillation, melting-reduction-oxidation, melting-oxidation-distillation, microwave leaching-cloud point extraction, distillation-melting-reduction, melting-reduction-oxidation, ion exchange, oxidation volatilization, electrolysis, biosorption and physical adsorption are introduced respectively. The advantages and disadvantages of existing ruthenium waste recovery technologies are summarized. And the development direction of ruthenium waste recovery technology in the future is prospected.

The leaching of magnesium from lightly fired powders obtained from low temperature calcination of magnesite by hydrochloric acid acidification was studied. The effects of addition method of hydrochloric acid, concentration of hydrochloric acid, liquid volume/solid mass ratio, external force way and reaction time on magnesium leaching rate were investigated. The leaching kinetics of lightly fired powders under ultrasonic condition was analyzed by using shrinkage core model. And the particle size distribution, mineral composition and mineral distribution characteristics of leaching residue were further analyzed. The results show that under the conditions of slowly adding hydrochloric acid, hydrochloric acid concentration of 14.8%, liquid volume/solid mass ratio of 9.8/1, stirring speed of 400 r/min and leaching time of 12.5 min, the leaching rate of magnesium can reach 70.48%. Using ultrasound can cause hard agglomeration to produce cracks or disintegration, which is beneficial to solid-liquid mass transfer, and the magnesium leaching rate is increased to 90.56%. The leaching process of lightly fired powders conforms to the mixed control model of surface chemical reaction and product layer diffusion. The ratio of magnesium to oxygen in the hard agglomeration is 1.33, the edge is 1.65, and there is a large amount of unreacted magnesium in the hard agglomeration. The particle size of the leaching slag is reduced from 42.61 μm to 24.39 μm by ultrasonic action. The ultrasonic bubble vibration force and the shock wave formed by the cavitation collapse can effectively prevent the formation of hard agglomeration or make the hard agglomeration re-disaggregate.

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.

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.

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 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.

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.