To solve problems of poor selectivity, thick foaming and large reagent consumption in recovering spodumene with fatty acid collectors, anionic and cationic collectors were introduced to flotation tests of spodumene, feldspar and quartz. According to the results of pure mineral tests, a anionic-cationic collector can enhance the synergistic effect of reagents, and improve the grade and recoveries of concentrates. CFLH-18, a combination of anionic and cationic collectors, was introduced in a close-circuit flotation test of granite pegmatite-type spodumene from Jinchuan County of Sichuan Province, and a spodumene concentrate with Li₂O grade of 4.62% was collected at 78.54% recovery. Compared with the on-site practice using fatty acid collectors, Li₂O grade and recovery are improved by 0.10 percentage points and 5.93 percentage points. Meanwhile, the concentrate enrichment ratio is raised from 3.77 to 4.57.

To reasonably select the composition of molten slag for efficient enrichment of rare earth elements therein, the viscosity and melt structure of mixed rare earth slag under different binary basicity conditions were explored using rotating cylinder method, FTIR, Raman spectroscopy, and X-ray photoelectronic spectroscopy. The results show that with the binary basicity of 0.50, 0.86, 1.00, and 1.20 respectively, the corresponding viscosity of the slag system at 1 550 ℃ is 1.30, 0.87, 0.60, and 0.36 Pa·s, and the activation energy of the viscous flow unit is 268, 220, 216, 202 kJ respectively; the area fractions of Q¹ (Si) and Q² (Si) in the molten slag are all more than 24%. As the binary basicity increases, the area fraction of bridging oxygen (O⁰) decreases, and the area fractions of non-bridging oxygen (O^-) and free oxygen (O^2-) decrease, and the K value representing the polymerization degree of slag gradually decreases from 0.53 to 0.10. It is found that the structure system of molten slag tends to be simple with the increase of binary basicity, which is the main reason for decrease in the viscosity of a mixed rare earth slag.

The leachate obtained from the oxidation leach of nickel-cobalt-iron powder with sulfuric acid was taken in the study for preparing iron phosphate. After potential adjustment, Al³⁺ and Cr³⁺ in the leachate were removed by neutralization and precipitation to achieve an efficient separation of Fe²⁺ and Al³⁺. The purified solution was then oxidized and used to prepare ferric phosphate hydrate by iron precipitation with phosphoric acid. Finally, the purified Ni-Co-rich solution was used to prepare nickel-cobalt hydroxide. It is found that firstly, with pH of the leachate at 4.5, 10 min of reaction at 25 ℃ can lead to the removal rates of Al and Cr reaching 100% and 97.15%, with loss rate of Fe at 2.42%; secondly, the obtained purified solution is subjected to 10-min iron precipitation at 25 ℃ with pH of 2.1, resulting in iron precipitation rate of 97.30%, loss rates of Ni and Co at 0.36% and 0.64%, respectively; the precipitate, amorphous iron phosphate with water of crystallization, is then subjected to 2-h calcination at 700 ℃ and converted to anhydrous FePO₄, with both impurity content and iron-phosphorus ratio up to the standard of type I anhydrous iron phosphate in HG/T 4701—2021.

The effect of heat treatment parameters on the microstructure and properties of QAl11-6-6 aluminum bronze alloy extruded rod was explored by performing orthogonal test, in combination with metallographic microscope, X-ray diffractometer, scanning electron microscope and hardness tester. The results show that the microstructure of extruded aluminum bronze alloy consists of α, κ (AlFe, AlFe₃, AlNi), γ₂, and the remaining β′ phases; the heat treatment including solid solution and aging can effectively improve the hardness of the alloy extruded rod; the influence of four process parameters on the hardness of the alloy is in the following descending order: aging time > aging temperature > solid solution time > solid solution temperature. The sample was quenched by water cooling after solid solution at 910 ℃ for 45 min, and then treated by aging at 450 ℃ for 150 min. The hardness of the alloy was increased to 40.1HRC from previous 33.4HRC in the extruded state, presenting obvious age hardening effect. It is found that precipitation of more martensite-like β' was the main reason for significant increase in hardness of the alloy after aging treatment.

A beneficiation flowsheet comprised of two stages of roughing for copper-sulfur bulk flotation, bulk concentrate regrinding and Cu/S separation was adopted for optimization of beneficiation technique for a high-altitude copper ore. By applying asynchronous flotation for Cu-S bulk flotation and using KMY-1, a copper collector with good selectivity for Cu/S separation, efficient recovery of refractory copper minerals with microfine-grained dissemination can be actualized. A laboratory closed-circuit test finally produced a copper concentrate grading 23.06% Cu at 78.29% recovery, up by 2.92 percentage points and 9.59 percentage points correspondingly compared to the copper concentrate yielded from the on-site processing flow.

A high-strength Al-Si-Mg alloy was prepared by adopting selective laser melting (SLM), and then compared to the as-cast Al-Si-Mg alloy in terms of phase composition, microstructure, element distribution, crystallographic characteristics, and mechanical properties. It is found that Al-Si-Mg alloy prepared by SLM consists of α-Al matrix and eutectic Si particles, and the diffraction peaks of α-Al solid solution shift to lower angles due to the solid solution strengthening effect of Fe and Mg elements. The Al-Si-Mg alloy prepared by SLM has grain size approaching 18.35 μm, the dislocation density of 1.91×10¹⁵/m², the surface hardness of (117.8±4.7) HV, the tensile strength of (436±13) MPa, and the elongation of (7.98±0.27)%, presenting superior performance than the as-cast Al-Si-Mg alloy. The alloy prepared by SLM technology is under the synergetic effect of fine grain strengthening, solid solution strengthening, dislocation strengthening and second phase strengthening, and the ductile fracture is its main failure mechanism.

The traditional formula for prediction of blast-induced vibration has low accuracy, thus a prediction model for blast-induced vibration velocity in open-pit mines was constructed based on bidirectional long-short-term memory network (Bi-LSTM). This model can process time series data in both directions while capturing the dependency between inputs of the past and future information at upper and lower layers and the outputs. From the monitoring data of blasting operation in Gaocun Iron Mine of Maanshan Iron and Steel Group, the relevant data were selected as the inputs, and the prediction results by Bi-LSTM were compared with those based on Sadaovsky formula. The results show that the blast-induced vibration velocity predicted based on Sadaovsky formula has a mean error of 26.87%, and the blast-induced vibration velocity predicted by Bi-LSTM algorithm has a mean error of 8.95%. It is shown that the Bi-LSTM model can have the prediction results in a high degree of agreement with the measured results. In the future, this Bi-LSTM model will be trained with the monitoring data of other mines to improve its generalization ability, and also will be implanted by transfering learning into a real-time safety monitoring and early warning platform for mines.

An experimental study with a novel flotation reagent was carried out for some refractory low-grade polymetallic ore from Henan Province, and a process of Cu-Mo bulk flotation, followed by Cu/Mo separation was adopted in the experiment. With a processing flow consisting of a Cu-Mo bulk flotation (including two stages of roughing, one stage of cleaning, and two stages of scavenging) with L43 as a collector and L56 as a frother, followed by regrinding of the obtained Cu-Mo bulk concentrate, and Cu/Mo separation (including one stage of roughing, three stages of cleaning and three stages of scavenging) with L789 as a depressant, the experiment produced a molybdenum concentrate grading 50.780% Mo, 0.602% Cu with 65.30% Mo recovery and 4.72% Cu recovery, and a copper concentrate grading 0.165% Cu and 0.362% Mo with recoveries of 4.49% Cu and 1.61% Mo. It is shown 90.79% Cu is recovered into the mixed tailings.

In order to clarify the mass transfer law in the process of salt conversion into corresponding acid and base by introducing bipolar membrane and thus to instruct industrial production with it, a model of electrodialysis unit cell with Na₂SO₄ as the raw material was constructed by introducing bipolar membrane (BPM) based on Nernst-Planck and Poisson equations. Key parameters including the number of grids and the capacity of membrane groups of the unit cell were obtained by calculating with COMSOL Multiphysics software. The salt conversion rates in the unit cell with different voltage and feed concentration were calculated based on simulation, and then compared with the experimental data. The results show that with the grid number of 30 000 and the membrane group capacity of negative/positive membrane at 300 mol/m³, the simulated results with the constructed model are in good agreement with the measured data. Based on the corresponding calculation, data of potential distribution, ion distribution and distribution of ion migration flux in the unit cell during mass transfer process were obtained. It is found that the mass transfer rate and energy efficiency of Na₂SO₄ converted into corresponding acid and base by bipolar membrane are mainly influenced by voltage drop and membrane voltage in the unit cell.

The mechanism for calcite depression with esterified starch was investigated by performing flotation test, surface tension test, zeta potential measurement and infrared spectroscopy analysis. The results show that, compared with ordinary starches, the esterified starch serves as a significantly stronger depressant for calcite. The esterified starch with bipolar functional groups can be chemisorbed onto calcite, reducing the contact angle of calcite surface and increasing its hydrophilicity. It also causes a negative shift of zeta potential of calcite, therewith, enhancing dispersion of calcite particles and effectively reducing hydrous entrainments in flotation products. In the flotation system using sodium oleate as the collector, esterified starch, possessing greater steric hindrance than sodium oleate, can prevail in their competitive adsorption and hinder the adsorption of sodium oleate.