Based on the time-domain coupling analysis method, a three-dimensional nonlinear hydrodynamic model for mother vessel, deep-sea mining equipment and umbilical cable was established, and numerical calculation and analysis were also conducted for the hydrodynamic response characteristics of umbilical cable during launch and recovery. The results show that deep-sea mining equipment (weighing 10 t in water) can be safely launched and recovered at a speed of 0.8 m/s under condition of sea state 4. Due to the influence of both waves and currents, the deep-sea mining equipment will have strong oscillations and swings at the beginning of launch and at the end of recovery, which can be reduced by installing anti-swaying devices.

Nano ITO powders prepared by chemical coprecipitation plus calcination process were used as raw materials to prepare ITO sputtering target by molding and cold isostatic pressing, as well as conventional sintering. The effects of molding pressure on the relative density, resistivity, and grain size of ITO target were investigated. The results show that with the molding pressure of 60 MPa and the appropriate sintering conditions, the prepared ITO target has the relative density of 99.81% and resistivity of 1.707×10^-4 Ω·cm, with an average grain size of 7.62 μm. The research results can provide reference for densification and large-scale production of ITO sputtering targets.

Based on typical nonlinear negative exponent constitutive relations and catastrophe characteristic of weakened mineral rock, the variation of energy transformation and time effectiveness with mechanism stiffness in catastrophic and non-catastrophic breakup were analyzed. The results show that the catastrophic breakup induced by low mechanism stiffness will dramatically reduce the energy transformation efficiency of dynamical system and time effectiveness of rock breakage. From the perspective of energy utilization and rock-breaking efficiency, it is not appropriate to equip a dynamical system for rock breakage with low mechanism stiffness. Finally, an appropriate range of mechanism stiffness is provided for reference in design.

Experimental studies on comprehensive recovery of valuable resources in iron-dressing tailings with TFe grade of 15.70% were conducted by adopting processes consisting of Cu-S bulk flotation, high intensity magnetic separation to reclaim Fe minerals, roasting reduction of Fe minerals, and shaking table gravity separation and flotation separation to recover barite and mica. As a result, the experiment produced an iron concentrate with TFe grade of 60.17%, S content of 0.11% and iron recovery of 66.74%, a sulfur concentrate grading of 47.86% S at 66.58% recovery, a copper concentrate grading 19.79% Cu at 31.24% recovery, a barite rough concentrate with BaSO₄ content of 86.96% and recovery of 9.15%, and a mica concentrate with K₂O content of 6.66% and recovery of 6.63%, respectively. In this way, comprehensive utilization of tailings can thus be realized.

The project of transition from open-pit to underground mining in Panzihua Iron Mine was taken for study. Based on the analysis of relationship between storage and discharge in the stope, it is predicted that the accumulated water in open pit will be maximally 5 m deep in the event of a 50-year extreme rainfall, which has little influence on the stability of crown pillar. Numerical simulation of seepage in the case of fault occurring at the bottom of pit shows that fault zones are the main leakage channel of crown pillar. Some special anti-seepage measures can be taken to effectively reduce the leakage of crown pillar.

The influences of physical and mechanical properties of overlying filler on the shear strength characteristics of composite liner interface were studied by adopting a modified ZLB-1 triple rheological direct shear apparatus, and shear stress-strain curves of overlying filler under different normal stresses were obtained. The experimental results show that both clay and sand present displacement softening behavior, which becomes more obvious with the increase of sand content. Among the interface of composite liners, the interface between geomembrane and sodium bentonite pad has the lowest friction coefficient, and the friction coefficient in saturated state is significantly lower than that in the unsaturated state. As the sand content increases, the pseudo-cohesion between the interface of composite liner decreases, while the pseudo-friction angle initially decreases, and then increases followed by another decrease. As the water content increases, both the pseudo-cohesion and pseudo-friction angle decrease after an initial increase.

In order to determine the reasonable air-deck length in underground vertical deep-hole blasting, the internal distribution function of impact pressure on hole wall with different air-deck length in multi-stage air deck blasting was analyzed based on the detonation wave theory. According to the Mises criterion, the reasonable reference values of air-deck length were obtained for different kinds of rock, which was verified by numerical simulation and on-site blasting test. The results show that the impact pressure on the hole wall of the air deck drops abruptly from both sides to the center along the axis of the hole, but increases slightly around the midpoint, and the pressure distribution presents a symmetrical W-shaped curve, with much higher values on two sides, lower in the middle section, and slightly higher around the center.

Experiments were performed to study the effect of quaternary ammonium salt Y28, as a collector, on the flotation performance of diaspore and gangue silicate minerals of kaolinite and muscovite, and the interaction mechanism between Y28 and the surface of minerals was also explored by analyzing adsorption capacity, contact angle, zeta potential, FTIR analysis and XPS analysis. The results show that with the collector Y28 at a dosage of 90 mg/L and pulp pH of 7, the recoveries of diaspore, kaolinite and muscovite were 25.63%, 83.21% and 81.24%, respectively. The collector Y28 is primarily adsorbed onto the surface of the minerals by physical adsorption, with the adsorption strength in the following descending order: kaolinite>muscovite>diaspore.

Effects of elements Ti and N on the precipitation behavior of TiN inclusions during the solidification of Timicroalloyed high-strength steel were studied by thermodynamic calculation and microscopic analysis. Thermodynamic calculation results indicate that the precipitation of TiN inclusions is unavoidable at the solidification front, but can be delayed by reducing the value of w(N)₀×w(Ti)₀. The final size of TiN inclusions is mainly affected by the initial nitrogen content in molten steel, and TiN inclusions can be smaller by reducing the initial nitrogen content. Microscopic analysis shows that with the contents (mass fraction) of Ti and N decreasing from 0.12% and 0.005% to 0.08% and 0.003%, respectively, the number density and average size of TiN inclusions can be decreased by 27.1% and 50.2%, which also confirms the thermodynamic calculation results.

With spent lithium manganese iron phosphate cathode powder as raw material, a leaching system of DL-malic acid combined with sodium persulfate was employed to selectively recover Li, Mn and Fe elements. The effects of factors, including DL-malic acid concentration, molar ratio of Na₂S₂O₈ to LiFe_0.4Mn_0.6PO₄, liquid-to-solid ratio, leaching temperature, and leaching time on the leaching rates of Li, Fe, Mn and P were investigated. Then, the left leaching residue was analyzed by using SEM and XRD, and the leachate was analyzed by FTIR. Results show that with DL-malic acid at a concentration of 0.4 mol/L, Na₂S₂O₈ and LiFe_0.4Mn_0.6PO₄ at a molar ratio of 0.4, liquid-to-solid ratio of 15 mL/g, 3 h leaching process at 30 ℃ can bring the leaching rates of Li, Fe, Mn and P at 98.76%, 2.37%, 96.89% and 52.45%, respectively, and also Li, Fe, Mn and P in the leachate in a mass concentration of 2.98, 0.21, 12.66 and 6.52 g/L, respectively. It is found that iron phosphate is the dominant component in the leaching residue. During the leaching process, DL-malic acid and Mn²⁺ form a complex that can be solved in leachate, leading to efficient separation between iron and manganese.