The process of extraction and separation of indium and Fe(III) requires a step of reduction of trivalent iron in advance and also emulsification is prone to occur. In order to solve the problems, an experimental study was carried out with acid leaching solution of volatile dust from a domestic large-scale zinc smelting enterprise to explore the processing technique of direct extraction with a extractant system of DY23 (a combination of extractant A and co-extractant M) to recover indium without a step of reduction of Fe(III) in advance. Based on the experiment, effects of organic phase concentration, phase ratio in extraction, extraction time and temperature on the separation between indium and Fe(III) were investigated. It is found that with a combined extraction system, consisting of 30% extractant A, 10% co-extractant M and 60% sulfonated kerosene, O/A ratio of 1∶1, the leaching solution of volatile dust is subjected to a two-stage countercurrent extraction at room temperature for 1.5 min, leading to indium extraction rate exceeding 99% and extraction rate of Fe(III) at only around 10%, presenting a good separation effect. The loaded organic phase is then subjected to a stripping process with 4 mol/L hydrochloric acid after being washed with 200 g/L sulfuric acid, leading to the stripping rate of indium exceeding 95%. After stripping of indium, the organic phase is subjected to another stripping with 70 g/L oxalic acid to remove Fe(III), resulting in the stripping rate of Fe(III) up to 98%. It is concluded that indium and Fe(III) therein can be effectively separated.

The additive manufacturing of SiC_p/Al606 by photocuring process was studied, and the effects of resin monomer and solid volume fraction on the stability, rheological properties and photocuring performance of SiC_p/Al6061 slurry, as well as the compactness and microstructure of sintered product were explored. The results show that as photosensitive resins of PEG200DA and PEG400DA mixed at an appropriate ratio of 1∶1, the prepared slurry with content of 52.5%, viscosity of 5.05 Pa·s (shear rate of 10 s^－1) and single-layer curing thickness of 100.3 μm can meet the requirements for photocuring in additive manufacturing. The SiC_p/Al component manufactured by photocuring process can have a complete structure and good interlayer bonding, and the sintered product with no cracks and obvious necking presents relatively high compactness (94.07%).

With the red mud from Guizhou as raw material, an experiment was carried out by adopting a process of low-temperature acidification roasting followed by water leaching to recover scandium, and effects of factors, including sulfuric acid dosage, temperature and time for roasting process, liquid-solid ratio of leaching solution, leaching temperature and time, on scandium leaching rate were investigated. It is shown that after 4 h-roasting at 200 ℃ with sulfuric acid and raw ore in a mass ratio of 1∶1, and then 4 h-leaching at 80 ℃ with leaching solution and solid in a mass ratio of 6∶1, the leaching rate of scandium can be finally up to 89.10%.

A discussion on collaborative development of low-altitude economy (LAE) and mining & metallurgical engineering (MME), as well as the two-way empowerment mechanism is presented. Low-altitude technologies, such as unmanned aerial vehicle (UAV) and electric vertical take-off and landing aircraft (eVTOL), can be used to reshape MME, while MME can provide core materials for low-altitude aircraft. However, the collaboration between them is limited by disciplinary barriers and talent gaps, so it is necessary to build a dual system of “technology chain－talent chain”. This can be achieved by adding interdisciplinary courses, establishing actual flight certification bases in mining areas, promoting integration of relevant qualification certifications, and accelerating incubation of key technologies based on low-altitude economic industrial parks. These measures can break down discipline barriers, shorten the cycle of technology transformation, and provide support for the in-depth integration and collaborative development of LAE and MME.

An intermittent sedimentation test was performed for vanadium-titanium magnetite tailings to obtain settling curves of flocculated tailings, and then the solid flux in sedimentation by flocculation was calculated by Coe-Clevenger equation and material balance calculation. An innovative Φ38 m heavy-duty and efficient thickener is designed to have a unit area processing capacity of 1 000 kg/(m²·h). The industrial application of this thickener in dewatering of vanadium-titanium magnetic tailings show that with dry ore processing capacity of 1 100 t/h and the feed concentration of 20%－25%, its underflow has concentration of 45% and the overflow has solid content less than 200 mg/L. It is concluded that such thickener can solve the technical problems in the production faced by enterprises, and also bring enterprises enhanced economic and environmental benefits.

An experiment was carried out on treating high-salinity wastewater by air gap membrane distillation (AGMD). Effects of different operating conditions on the performance of AGMD were investigated, and membrane fouling and its control measures were also analyzed. It is shown that the permeation flux increases with the increase of temperature and flow rate of feed, and decreases with the increase of cooling water temperature and salt concentration. The salt rejection rate can maintain above 99.8% with the salinity less than 60 g/L, and still exceed 90% with salinity within the range of 60－100 g/L. It is concluded that AGMD technology can be adopted to treat high salinity wastewater.

The parameters of the Fuzzy Measure Method (FMM) in slope stability analysis are difficult to determine, thus a support vector regression (SVR) model was established and used to accurately predict parameters of the FMM, and a slope stability prediction model, FMM-SVR, was established, which was then used to predict the instability probability of the slope during the second-phase open-pit mining in Gaocun Iron Mine of Masteel Mining Resources Corporation. The results show that the maximum slope instability probability is 0.120 8 as mining operation approaches the toe of slope in an open pit, indicating that the slope remains overall stable with a risk of partially instability. This conclusion is also consistent with the on-site measured results. The location of the most critical sliding surface of the slope was determined by the finite element strength reduction method, and the factor of safety is calculated to be 1.5, which further verifies the effectiveness of the FMM-SVR model.

A beneficiation experiment for super enrichment was carried out with the low-grade niobium ore from western zone of Bayan Obo mine. In the experiment, a process of magnetic separation followed by gravity concentration for tailings discarding was firstly adopted for pre-concentration, and the obtained rougher concentrate grading 2.61% Nb₂O₅ was subjected to a reverse flotation for desulfuration, followed by a direct flotation with CYN-7 as a collector and CYD-2 as a depressant for recovering Nb minerals, resulting in efficient separation between Nb and other gangue minerals. It is found that the raw ore grading 0.06% Nb₂O₅, with a grinding fineness of－0.074 mm 85% is treated by magnetic separation and gravity concentration for tailings discarding, followed by a reverse flotation for desulfuration, and a direct flotation consisting of one stage of roughing and three stage of cleaning. As a result, a Nb concentrate grading 22.37% Nb₂O₅ at 33.64% recovery can be finally obtained.

Single mineral flotation tests of chalcopyrite oxidized respectively in air and water were carried out under optimized conditions such as pulp pH and collector dosage. The mechanism for oxidation bringing effect to the floatability of chalcopyrite was studied by measuring contact angle and Zeta potential, and using infrared spectroscopy. The results show that the recovery of oxidized chalcopyrite with collector JXZZ is higher than those using DJHY and BXZX; the surface hydrophobicity of chalcopyrite oxidized in air and water can be improved; the area of CO₂ absorption peak increases with the increase of air oxidation time, air oxidation temperature and water oxidation time, and all the three collectors can be chemisorbed on chalcopyrite. After oxidation, point of zero charge of oxidized chalcopyrite shifts positively, while the oxidization state of chalcopyrite in water is comparatively stable. It can be concluded that the floatability of chalcopyrite can be regulated by surface oxidation of this ore.

To investigate the fracture characteristics of rocks with bent cracks under saturated condition, uniaxial compression tests were conducted for rock specimen with different inclination degrees and numbers of crack bends under saturated conditions to study load-displacement curves, peak strength, acoustic emission characteristics, crack initiation modes, and penetration modes of the rock specimen. The results show that the load-displacement curve of saturated rock specimen with bent cracks presents one-peak or double-peak shape, with peak strength increasing after an initial decreasing as the crack inclination angle becomes larger. The acoustic emission signals become stronger as the crack inclination angle becomes larger and the number of crack bends increases. Cracks mainly initiate at the tip and bends, and mainly penetrate directly or run without penetration.