With aluminum hydroxide powder as raw material, aluminum hydroxide was roasted into α-Al₂O₃, and the phase transformation and microstructure change during the process were investigated. Then, the kinetics of the calcination process was calculated by simulation with multiple scanning method. It is found that the optimum conditions for aluminum hydroxide calcinated into α-Al₂O₃ are as follows: calcination temperature of 1200 ℃, time of 2 h, heating rate of 5 ℃/min. Three endothermic peaks can be observed during the calcination process of aluminum hydroxide, corresponding to three weightlessness stages. In the first stage of reaction, the function of mechanism is G (α)=[(1-α)^-1/3-1]², the average activation energy is 91.16 kJ/mol and the pre-exponential factor is between 17.00×10⁹ and 44.03×10⁹ min^-1. In the second stage of reaction, the function of mechanism is G (α)=α², the average activation energy is 106.2 kJ/mol and the pre-exponential factor is between 7.70×10⁹ min^-1 and 18.60×10⁹ min^-1. In the third stage of reaction, the function of mechanism is G (α)=α^1/4, the average activation energy is 235.42 kJ/mol, and the pre-exponential factor is between 39.94×10⁹ and 50.79×10⁹ min^-1.

Aluminum sulfate, sodium hydroxide, and high-aluminum pickling sludge were used as raw materials to prepare pseudo-boehmite by adopting a dual aluminum source method. The effects of pH value, reaction temperature, and urea addition on the formation and structure of pseudo-boehmite, as well as the effects of synthesis conditions on the phase and structural properties of pseudo-boehmite were investigated. The results show that as the reaction temperature increases, the specific surface area and pore volume of pseudo-boehmite increase, and the crystallinity also increases. With pH value between 6.5 and 9.5, a clear pseudo-boehmite phase can be obtained; with pH value up to 10.5, a trihydrate alumina phase will be formed. The addition of urea can significantly increase the specific surface area and pore size of pseudo-boehmite.

With micron silicon powder as matrix, phosphorus-doped silicon-carbon composite material (Si-P@C) was synthesized by solid-state thermal diffusion and high-temperature pyrolysis, and then used as anode material of lithium-ion batteries. The results show that Si-P@C anode material demonstrates an initial discharge specific capacity up to 2164 mAh/g at a current density of 0.2 A/g. Compared with pure silicon, Si-P@C anode material presents greatly improved cycling performance. After 50 cycles at a current density of 0.5 A/g, it demonstrates a high reversible specific capacity of 1 176 mAh/g, with the capacity retention ratio of 73.5%. It is concluded that phosphorus-doping and carbon coating can effectively improve the electron transfer ability and reaction kinetics of silicon anode.

Theoretical calculation was made for the flow field in the hydraulic transportation with deep-sea polymetallic nodule collector, and the relationship between particle size of polymetallic nodules and minimum conveying speed was obtained. The distribution of flow pattern in the conveying channel was simulated with the jet velocity of nozzle at 15 m/s, 20 m/s and 25 m/s respectively, and rate of the flow at 30 mm away from the lower surface of the channel was measured. A laboratory test was conducted for nodules pick-up by using a collector with different jet velocities of nozzles, and it is found that the obtained results are consistent with the theoretical calculation and simulation results.

In order to simply and effectively evaluate slope stability, four machine learning models based on chaotic particle swarm optimization (CPSO) were proposed to solve the existing problems of algorithm selection and hyper-parameter optimization in traditional machine learning model, and their prediction performance were comprehensively compared among each other. A database consisting of 221 open-pit slope stability cases was established, in which 80% of the data were used for training and 20% for model testing. Based on the comparison between the prediction results of four models and the verification results of engineering practices, it is found that the support vector machine (SVM) based on CPSO is superior than other three machine learning models in terms of prediction of slope stability, presenting an accuracy up to 88%. Thus, it can provide a reliable prediction for the safety of slope in open-pit mine.

Methylene blue was degraded by adopting a heterogeneous Fenton system composed of manganese residue and H₂O₂, and the effects of initial pH value, H₂O₂ concentration, dosage of manganese residue and reaction temperature on the degradation performance were studied. The reusability of manganese residue was investigated, and the removal mechanism of methylene blue in the manganese residue/H₂O₂ system was also discussed. The results show that the removal rate of methylene blue can exceed 98.1% after 120 min reaction at temperature of 25 ℃, with methylene blue concentration of 20 mg/L, H₂O₂ concentration of 10 mmol/L, manganese residue dosage of 2 g/L, and initial pH value of 2.5. After the manganese residue is recycled for 5 times, the removal rate of methylene blue can be still up to 95.5% by 300 min reaction. In the manganese residue/H₂O₂ heterogeneous Fenton system, ·OH plays a leading role in the degradation of methylene blue.

Based on the in-depth investigation of the geological characteristics of the phosphate mines in western Hubei, including Sujiapo Phosphate Mine, Maping Phosphate Mine and Taoyuxi Phosphate Mine, rock burst phenomena were analyzed in terms of influencing factors of occurrence position, buried depth and lithology. The appropriate control measures are proposed for rock burst in those phosphate mines in western Hubei. In-situ stress of underground phosphate rock in western Hubei was tested. Based on the obtained results, the mining sequence was optimized to avoid mining operation in the stress concentration area as much as possible, and pressure relief and support measures were taken in local areas to ensure safe underground mining.

As for a zinc concentrate collected from mineral processing of a lead-zinc ore, an experimental study was carried out to reduce the carbon content therein. With soluble starch as the carbon depressant, a concentrate with Zn grade of 48.71%, carbon content of 0.86% and Zn recovery of 90.28% was obtained from a closed-circuit test. Compared with the on-site indicators, both the Zn grade and recovery of concentrate are increased by using this new process, while the carbon content therein is reduced to less than 1%, showing a remarkable carbon-reduction effect.

MIL-53(Fe), a metal-organic framework (MOF) material, prepared by using solvothermal synthesis was adopted to adsorb Sb(Ⅲ) in soil. MIL-53(Fe) was used as the adsorbent to adsorb the Sb(Ⅲ) in aqueous solution, and the effects of solution temperature, pH value, adsorbent dosage, initial concentration of Sb(Ⅲ), and humic acid content on adsorption performance were explored. Then, the isotherms and kinetics of adsorption were also analyzed. After 15 d remediation with the adsorbent at an amount of 3%, the TCLP testing shows that the concentration of leachable Sb(Ⅲ) decreases by 94.2%. However, the pH value and humic acid content of the solution have little effect on the adsorption performance. For 25 mL solution with concentration of Sb(Ⅲ) at 10 μg/mL, addition of 20 mg MIL-53(Fe) can bring good adsorption effect. The initial concentration of Sb(Ⅲ) has a significant impact on the adsorption of Sb(Ⅲ) by MIL-53(Fe). At equilibrium, the maximum adsorption capacity of the adsorbent is 102.9 mg/g. The adsorption isotherm of this process fits with the Freundlich model, and its adsorption kinetics can be described using pseudo-second order model.

The comprehensive recycling ways for tailings after vanadium extraction, including recovery of valuable components, synthesis of new functional materials and preparation of multi-purpose building materials, were explained, which can provide a reference for application of technologies in comprehensive recycling of tailings after vanadium extraction.