The parameters of lifter bars in the design of a Φ12.2 m×6.7 m semi-autogenous grinding (SAG) mill liner for the Las Bambas concentrator in Peru were optimized by employing discrete element method, and a quadratic regression model was constructed based on response surface analysis to investigate the effect of various factors on total collision energy and energy dispersion. The results indicate that lifter height has a significant impact on particle motion behavior, and it can alter drop height, particle trajectory and moving range, thereby impacting the collision energy during grinding process. The face angle and width of lifter can influence the distribution of collision energy by adjusting particle positions in the cascading and grinding zones. Based on a comprehensive consideration, the optimal lifter parameters are finally determined as follows: height of 380 mm, width of 100 mm, and face angle of 30°.

To gain an in-depth understanding of research status of ceramic additive manufacturing, the technical processes of direct ink writing, fused deposition modeling, selective laser sintering, stereolithography and digital light processing, as well as the materials used in those technologies are reviewed based on domestic and international researches on ceramic additive manufacturing. The advantages and disadvantages of those five technologies are summarized, which can provide references for their application scenarios. Finally, the prospect for the development of ceramic additive manufacturing is also discussed.

The relevant literature on laser-MIG hybrid welding of aluminum alloy from the China National Knowledge Infrastructure (CNKI) core journal database and Google Scholar database in 2000-2023 was systematically analyzed by using VOSviewer. Three primary research focuses were identified by analyzing citation frequencies of key literature and the evolution of research hotspots: ① the interaction between laser and MIG heat sources, particularly the effects of laser-arc distance and heat source leading modes on plasma behavior and molten pool stability; ② hybrid welded joints, revealing the formation mechanisms and optimization strategies for defects such as porosity and cracks by investigation into morphological characteristics; ③ mechanical properties of welded joints, focusing on microhardness distribution and softening mechanisms in the heat-affected zone. Results indicate that the transition of Mg and other alloying elements can be effectively achieved by adopting welding wire alloying, and after heat treatment of those heat-treatable aluminum alloys, the welded metal exhibit remarkably enhanced strength and hardness through aging. The subsequent researches can employ multi-scale numerical simulations to explore the dynamic coupling mechanisms between laser and arc, and the interaction between droplet transfer and keyhole stability, as well as to optimize process parameters to suppress porosity and overcome the technical bottleneck in simultaneously improving welding speed and quality. This review can provide insights for enhancing the performance of laser-MIG hybrid welding of aluminum alloy.

The immersion end quenching method, combined with hardness testing, metallographic microscopy, scanning electron microscopy and transmission electron microscopy, was used to investigate the effect of quenching rate on the age hardening of 6061 aluminum alloy for building formwork. Results show that when the quenching rate decreases from 305 ℃/s to 26 ℃/s, the post-aging hardness of the alloy remains nearly unchanged. However, when the quenching rate drops below 26 ℃/s, the hardness decreases rapidly with further reduction in quenching rate. At quenching rates below 26 ℃/s, solute atoms precipitate from the supersaturated solid solution during cooling, forming β (Mg₂Si) phases without strengthening effect at grain boundaries, Al₁₃ (Fe, Cr)₃Si₂ dispersoids, and dislocations. This reduces the number of β″precipitates in the grains after aging, thereby lowering the alloy hardness. Lower quenching rates result in more β phases and lower post-aging hardness. It is concluded that the quenching rate shall exceed 26 ℃/s for attaining high hardness alloy.

The western No.2 mining area of a certain mine adopts the non-pillar sublevel caving in mining, and excessive wedge cut height in the 1 546 m sublevel leads to poor blasting effect. To address this problem, blasting with wedge cut was specially studied. Firstly, the rock parameters were calibrated based on the RHT constitutive model and the damage threshold of the rock was determined to be 0.4 by a fluid-structure interaction analysis with the LS-DYNA software. A comparative analysis of the cut blasting effects with different cut width shows that with the cut height fixed at 23 m, the effective damage rate of the rock presents a unimodal distribution with an increase in cut width. The optimal cut width is found to be 24 m, with which the effective damage rate of the rock can reach a peak value of 0.692 5. Based on these parameters, the on-site application of designed cutting scheme indicates that over 85% of blast-forming space can meet the requirement, presenting a reasonable fragment distribution of muck pile, with the angle of repose at approximately 40°.

To achieve the separation of arsenic and antimony from high-arsenic antimony-containing dust, a selective oxidation roasting process was employed with barium oxide as an antimony-fixing agent. The effects of oxygen partial pressure, roasting temperature, roasting time, and the dosage of antimony-fixing agent on the volatilization rates of arsenic and antimony from the dust were explored. The results indicate that with pure oxygen flow rate at 40 mL/min, addition of barium oxide at an amount of 2%, and roasting at 450 ℃ for 60 min, the volatilization rates of arsenic and antimony in the dust can reach 90.46% and 6.79%, respectively. It is shown that the volatile products contain 99.53% As₂O₃ and 0.26% Sb, thus effective separation of arsenic and antimony from high-arsenic antimony-contained dust antimony can be actualized.

As for a mine in Yunnan, the failure modes of surrounding rock in roadways buried at a depth of 1 500 m was analyzed by adopting a combination of theoretical analysis, in-situ monitoring and numerical simulation for exploring the variation law of surrounding rock stress. The results indicate that the surrounding rock in the main transportation roadway and the drift transportation roadway near the ore body at a depth of 1500 m predominantly belongs to Class Ⅰ and Class Ⅱ rock masses. The influence of stratum stability on the broken zone is greater than that of the roadway cross-sectional dimensions. Under the disturbances of surrounding rock stress, mining-induced stress and blasting loads, the stress in the arch corner of the roadway is higher than that in the side walls. Based on the failure modes of the surrounding rock, a support method combining rock bolts, steel mesh and shotcrete was proposed. The 3DEC numerical simulation results show that after support, the depths of the plastic zones in the side walls, roof and floor of the roadway are reduced by 0.5 m, 0.8 m and 0.6 m, respectively.

Extreme high-speed laser cladding (EHLA) technology was used to prepare Al₂O₃-316L coatings on Ti6Al4V rods. The effects of scanning speed, powder feeding rate on single-track coating quality, and 316L powder content on multi-track coating quality and corrosion resistance were explored. Results show that with the following optimum process parameters, including scanning speed of 250 mm/s and powder feeding rate of 8 g/min, the coating can present superior quality with the 316L powder in a mass fraction of 20%. It is shown that all Al₂O₃-316L coatings exhibit superior corrosion resistance compared to the substrate. As 316L content increases, the corrosion resistance of coatings increases followed by decline. With 316L powder in a mass faction of 20%, the electrochemical impedance of the coating is 2.27 times that of the substrate.

Quartz crystal microbalance with dissipation (QCM-D) was used to monitor the micro-mass change during the gold leaching process for exploring the variation of gold leaching rate in cyanide solution. It is found that with a cyanide ion concentration of 55.2 mg/L and the dissolved oxygen concentration in the system increased from 1.5 mg/L to 8.5 mg/L, the leaching rate of gold can be increased from 430.9 ng/(cm²·min) to 514.8 ng/(cm²·min), up 19.5%; with the dissolved oxygen at the mass concentration of 8.5 mg/L, an increase in the cyanide ion concentration from 22.6 mg/L to 55.2 mg/L can lead to the gold leaching rate up to 514.8 ng/(cm²·min) from 60.1 ng/(cm²·min), presenting a 7.6-fold improvement. It is concluded that the gold-leaching rate has something to do with the ratio of cyanide ion concentration to dissolved oxygen concentration . The gold leaching rate is higher with at the room temperature.

Based on studies on the chemical phase-analysis methods for rubidium in some mineral ores from Hunan Shizhuyuan mine, the occurrence state and mass fraction of rubidium in minerals were preliminarily determined by using inductively coupled plasma optical emission spectrometer (ICP-OES), combined with XRD, SEM, electron probe and MLA. After the phase separation of rubidium was determined and appropriate selective reagents and reaction conditions were selected, rubidium in mica, rubidium in fluorite, rubidium in silica-aluminum oxide, rubidium in feldspar, and rubidium in insoluble minerals were all analyzed. Then, a method for rubidium phase analysis was developed. It is found that this analysis method is characterized by lower detection limit, high precision, good reproducibility, wider linear range, and simple and rapid process. Based on an experiment on the interference of alkali metallic elements in minerals, reasonable analysis methods were selected according to different concentrations of K, Na and Li, so as to obtain accurate results with less interference.