The granulated copper slag prepared by dry centrifugal granulation process was taken as oxygen carrier, a thermodynamic analysis and an experimental study were conducted for oxygen absorption and release reactions of copper slag. The effects of oxidation temperature, reduction temperature, particle size of copper slag and CaO addition on the phase composition of copper slag were investigated. The results show that the reactions of oxygen absorption and release of iron oxide in copper slag run step by step, and the granulated copper slag particles have certain capacity of oxygen absorption and release. Oxidation and reduction at higher temperature is beneficial to reactions of oxygen absorption and release of iron oxide in copper slag. Copper slag with smaller particle size is beneficial to the oxygen absorption reaction of FeO and Fe₃O₄, and addition of CaO is beneficial to the oxygen release reaction of copper slag.

The acid leaching solution of electrostatic precipitator dust from copper smelting has a high concentration of sulfuric acid, in which the iron and arsenic exist in the form of Fe³⁺and As⁵⁺, thus it is decided to adopt arsenic sulfide residue as the precipitant for copper precipitation. Firstly, an experiment was performed on the addition of arsenic sulfide residue in single Cu²⁺ and Fe³⁺ solution with different acid concentrations. Based on that, an experiment was performed for copper precipitation and arsenic leaching in the actual acid leaching solution. The results show that in the process of copper precipitation with arsenic sulfide residue, oxidation and reduction reactions between Fe³⁺ and S^2- occur firstly, which is followed by oxidation and reduction reactions of As⁵⁺ and S^2-, and finally a sulfurization reaction for precipitation of Cu²⁺. When the addition of arsenic sulfide residue is at an amount of 1.4 times the theoretical amount, it is shown that the copper precipitation rate is relatively higher, but the rate of arsenic dissolution is lower.

A basic polishing solution consisting of perchloric acid and methanol was optimized by adding citric acid and glycerol, and different kind of polishing solution was used for electropolishing of titanium nickel alloy wires. The surface morphology, corrosion resistance, and blood compatibility of untreated and polished wires were compared and studied. The results show that addition of citric acid and glycerol has a significant effect in corrosion inhibition and increases the controllability of the polishing process. With the optimized polishing solution, the surface of electropolished titanium nickel wire becomes flatter, with average roughness declined from 161.3 nm to 15.6 nm. The self-corrosion potential increases from -0.167 V to 0.045 V. The dissolved nickel content of phosphate buffer solution becomes lower, indicating the higher corrosion resistance. The hemolysis rate declines from 2.333% to 0.333%, and the number of adhesive platelet significantly decreases, thus the blood compatibility is enhanced.

In view of problems such as low grade of iron concentrate and low metal recovery for 0-15 mm fine ore in JISCO by adopting high-intensity magnetic separation process, experimental researches were conducted, including pre-concentration for tailings discarding, optimization of grinding-separation process and enhancing recovery of tailings by selective flocculation and magnetic seed magnetization. The results show that, the pre-concentration can effectively discard the surrounding rock and gangues that affect the separation indices, thus improving the grade of feed to grinding and separation. Tower grinding of rough concentrate can avoid overgrinding, and the recovery of magnetic concentrate can be increased by 5.32%, while concentrates have similar grade. Selective flocculation and magnetic seed magnetization can further improve metal recovery and reduce iron grade of tailings. An iron concentrate with TFe grade of 48.29% and recovery of 82.90% can be collected over the whole process. The scanning electron microscopy and infrared spectroscopy analyses show that caustic starch can establish bridges between target minerals and magnetic seeds, and it can be adsorbed onto target minerals mainly in the forms of chemisorption and hydrogen bonding, which can reduce the inclusion of gangue minerals in magnetic flocs and improve significantly the iron recovery while ensuring the iron grade of concentrate.

Electrolytic manganese anode slime (EMAS) was processed by adopting sulfur-based reduction roasting and sulfuric acid leaching to separate manganese and lead therein. The effects of roasting temperature, molar ratio of sulfur to manganese, roasting time, particle size of EMAS, stirring speed in leaching, leaching temperature, leaching time, solid-liquid ratio and sulfuric acid concentration on separation of manganese and lead were studied. The results show that with the optimized roasting conditions, including roasting temperature of 550 ℃, molar ratio of sulfur to manganese at 1∶1, roasting time of 50 min, EMAS at particle size of -0.177 mm, and optimized acid leaching conditions including stirring speed of 350 r/min, leaching temperature of 40 ℃, leaching time of 20 min, solid-liquid ratio at 1∶20, and sulfuric acid concentration of 2.5 mol/L, the leaching rate of manganese from EMAS can reach 97.4%, and the concentration of manganese ions in filtrate is 38.84 g/L, while the content of Pb in leaching residue is 45.26%. As a result, the effective separation between manganese and lead can be actualized.

Tailings slurry with different mass concentration and cement to sand ratio was prepared with a certain kind of tailings, which was taken to study for its rheological properties by adopting Brookfield R/S+ rheometer. It is found that at room temperature, the mass concentration of paste slurry has a stronger effect on the rheological properties of paste than the cement to sand ratio of slurry. When the concentration is lower than 64%, the cement to sand ratio has little effect on the rheological properties. As the slurry concentration increases, its yield stress and viscosity present exponential growth, which increase at the fastest rate when the slurry concentration is 68%. As the cement to sand ratio of slurry increases, its yield stress and viscosity increase approximately linearly. The influences of slurry concentration, cement to sand ratio, gradation and temperature on rheological properties of slurry were studied by experiments, and then the rheological parameters were predicted by using XGBoost based on the obtained experimental data. It is shown that the relative errors and variances between the predicted results and the actual values are within a reasonable range, which has proven the accuracy of the prediction model.

With Pr₆O₁₁ and CeO₂ as additives, B₄C matrix composite materials were prepared at 2 200 ℃, 1 900 ℃, and 1 700 ℃ by adopting techniques of pressureless sintering, hot pressing sintering, and spark plasma sintering, respectively. The relative microstructure and mechanical properties were also studied. It is found that PrB₆ and CeB₆ formed in situ can fill the pores between B₄C grains, and improve the density of the composites. Compared with pressureless sintering and hot pressing sintering, the technique of spark plasma sintering can bring the prepared composites with higher density. The fracture toughness of B₄C-CeB₆ composites can be improved due to its high relative density, as well as the deflection, branching and bridging of cracks occuring along CeB₆, which extends the expansion path of cracks and reduces stress concentration. The B₄C-CeB₆ composite prepared by spark plasma sintering has good comprehensive mechanical properties, with the relative density, vickers hardness, bending strength and fracture toughness reaching 99.3%, 34.7 GPa, 451 MPa and 4.38 MPa·m^1/2, respectively.

To address the problems of low recognition accuracy and slow speed of current plate shape pattern recognition methods, a pattern recognition model for cold-rolled strip plate shape based on IHPO-KELM was proposed. Firstly, kernel extreme learning machine (KELM) network was adopted to reduce the number of initial parameters in the network and improve the accuracy and speed of plate shape recognition. Secondly, Levy flight mechanism was added to the improved position update formula for linear combination by using the population of the predator algorithm initialized based on Sine chaos mapping, so as to improve the accuracy of the predator (HPO) algorithm, as well as to address the problem of HPO easily falling into local precocity during the iteration process. Then, the improved predator algorithm was used to optimize the regularization and kernel parameters of the KELM network model, as well as improve the accuracy of plate shape recognition. Finally, the Matlab simulation results have verified that the IHPO-KELM algorithm has the advantages of simple network structure, high convergence speed, and high recognition accuracy. The recognition accuracy of IHPO-KELM algorithm in identifying the measured data of 900HC reversible cold rolling mill of a company is higher than the KELM recognition model optimized with sparrow algorithm (SSA-KELM) by 58.8%, indicating a good generalization ability of IHPO-KEM recognition model. This provides a new idea for efficient and intelligent recognition of plate shape defects.

Based on a summarization of decomposition techniques of scheelite by hydrometallurgical process, the advantages and disadvantages of several decomposition techniques, such as decomposition with hydrochloric acid, soda sintering, pressure boiling of soda, decomposition with sodium hydroxide, decomposition with fluorine salt, decomposition with mixture of sulfuric acid and phosphoric acid, as well as lime sintering conversion followed by decomposition with ammonium bicarbonate were all analyzed. It is concluded that those three techniques, including decomposition with fluorine salt, pressure boiling of soda and decomposition with mixture of sulfuric acid and phosphoric acid, will gradually become the mainstream decomposition techniques for scheelite.

Aiming at the problem of high fragmentation by blasting in Baiyinnuoer Lead-Zinc Mine, the unit consumption of explosive and delay intervals between rows in a fan-shaped pattern of blastholes with medium depth were analyzed by numerical simulation with ANSYS/LS-DYNA. According to Von Mises yield criterion, the effective stress, peak value of vibration velocity, and rock damage area of the recorded unit were analyzed. The results show that with unit consumption of explosive at 1.16 kg/m³ and delay interval of 100 ms between rows, the effective stress, peak value of vibration velocity and rock damage area of the recorded unit all can meet the design requirements. The optimized parameters of unit consumption of explosive and delay interval were then applied in on-site blasting with blastholes in a staggered array. The muck pile after blasting was analyzed by using Split-Desktop 4.0, and it is found that the rock fragmentation by blasting is 4.34%, indicating that high fragmentation by blasting can be effectively controlled.