A mineral processing test was conducted to treat a lithium-tantalum-niobium-beryllium polymetallic ore with a lithium grade of 0.68% from Xinjiang. According to the process mineralogy study, this ore has spodumene as the dominant lithium minerals, and has low content of tantalum-niobium minerals. A flowsheet including a magnetic separation and gravity separation to recover tantalum-niobium minerals, and a flotation to collect lithium minerals can produce a tantalum-niobium concentrate with Ta₂O₅ grade and recovery of 17.110% and 41.69%, Nb₂O₅ grade and recovery of 19.670% and 42.63%, respectively, and a lithium concentrate with Li₂O grade and recovery of 5.12% and 75.21%, respectively.

LiMn_0.6Fe_0.4PO₄/C (LMFP) composite synthesized by a combined process of co-precipitation and solid-phase sintering not only has low impurity content, uniform phase distribution, but also exhibits excellent electrochemical performance. It is shown that such process can inhibit the formation of Mn₂P₂O₇ phase and improve the lithium ion diffusion rate of LMFP, while removing NH₄⁺ and H₂O. The Li-ion batteries assembled with LiMn_0.6Fe_0.4PO₄/C exhibit excellent electrochemical performance, showing initial specific discharge capacity of 145.5 mAh/g at 1C and 111.9 mAh/g at 5C. It is concluded that this process, being simple and cost-effective, is suitable for industrial production. Such study provides a feasible scheme in designing cathode materials for commercialized high-performance Li-ion batteries.

To recover the copper resource therein, mineral processing of a slag-beneficiated copper sulfide ore from Congo (Kinshasa) with 9.62% Cu was investigated. A regrinding and reseparation flotation process was proposed based on multi-element chemical analysis and mineral occurrence analysis. It is found that with this process, a copper concentrates with Cu grade of 25.16% and Cu recovery of 90.67% can be collected.

Ball milling was adopted to assist leaching of valuable metals from the cathode powder of spent batteries in citric acid and hydrogen peroxide system. It is found that ball milling can exert mechanical energy on the reaction solution, leading to changes in its structure and physical and chemical properties. As a result, chemical reactions can occur, which not only increases reaction rate, but also shortens leaching time. It is shown that after 30 min leaching at 60 ℃, with citric acid concentration of 0.8 mol/L, H₂O₂ at a mass fraction of 20%, liquid-solid ratio of 6∶1, and rotation speed of 60 r/min for a ball mill, the leaching rates of lithium, nickel, cobalt and manganese can reach 99.6%, 99.5%, 99.3% and 98.5% respectively. It is concluded that this processing technique, being characterized by low cost and high efficiency, can provide a certain reference for recycling of spent batteries.

In the flotation process of electrode materials from spent LiFePO₄ batteries, the occurrence of entrainment and entrapment usually leads to poor separation effect. Aiming at such problem, selective flocculation with polyvinylpiroxanone (PVP) and polyacrylic acid (PAA) was adopted to enhance the flotation effect in an experimental study, and the interaction mechanism between PVP and PAA and electrode materials was also analyzed. Results show that the firstly added PVP can be selectively adsorbed on the graphite surface by hydrogen bonding, thus inhibiting the spontaneous hydrophobic flocculation of graphite. Then, due to site-blocking effect, the subsequently-added PAA is inhibited to be adsorbed on the graphite surface, leading to selective flocculation of LiFePO₄ by PAA. A combined usage of PVP and PAA can not only make graphite effectively dispersed, but also lead to apparent particle size (D₅₀) of LiFePO₄ cathode material increased from 15.01 μm to 26.17 μm. As a result, the loss of LiFePO₄ due to entrainment in the flotation process of mixed electrode can be effectively reduced, thus the recovery rate of LiFePO₄ cathode material by flotation process can be improved from 71.41% to 83.59%.

Based on the combination of the hunger games search (HGS) algorithm and the artificial neural network (ANN), a new hybrid model of HGS-ANN was developed to predict blasting vibration. Four different prediction models were established based on group method of data handling (GMDH), support vector machines (SVM), ANN and Sadov's empirical formula, and compared with HGS-ANN model in evaluating the performance of models. For this purpose, 32 sets of blasting data of an open-pit mine were collected.7 independent variables, including detonation distance, maximum single-stage charge, total charge, burden, hole spacing, number of holes and hole depth were selected as inputs, while the particle vibration velocity was selected as the output. With the root-mean-square error (RMSE) and the decisive factor (R²) as the evaluating indicators, the established models was compared in terms of their performances. The results show that the HGS-ANN model, with the RMSE and R² of 0.833 and 0.963, respectively, has performance better than the other four models. It is proposed that the HGS-ANN model can be used as an auxiliary tool to optimize the blasting design for reducing the blasting-induced seismic effect.

In order to recover metal elements from the cathode materials of spent Li-ion batteries in an environmentally friendly and efficient way, three deep eutectic solvents (DES) were synthesized with choline chloride as hydrogen bond acceptor, malonic acid, succinic acid and adipate respectively as hydrogen bond donors. Then, Co and Li in the cathode materials of spent Li-ion batteries were leached by adopting these three DESs respectively. The effects of leaching time, liquid-solid ratio and reaction temperature on the leaching rates of Co and Li were explored, and the leaching residues were also characterized in terms of morphology and phase. The leaching mechanism was analyzed by FT-IR spectrum and UV-Vis absorption spectrum. It is shown that the leaching efficiency of metal elements can be enhanced by prolonging leaching time, increasing liquid-solid ratio and temperature. It is found that under the optimal conditions, including leaching time of 300 minutes, liquid-solid ratio of 100 mL/g, and temperature of 110 ℃, malonic acid-based DES, among those three kinds of DESs, can bring better leaching effect, with leaching rates of Co and Li all exceeding 99%. During the leaching of lithium cobalt oxide with those three DESs, Co exists in the form of bivalent in the leaching solution, and the coordination compound is in a tetrahedral structure.

In order to optimize the particle shape and gradation of machine-made sand, a vertical bar stirring mill was adopted for shaping tests. The effects of medium type, medium ratio, mill rotation speed and material/ball ratio on the particle shape of machine-made sand were investigated. The gradation and shape characteristics of unshaped and shaped sands were comparatively analyzed by using optical microscopy and image processing software. The results show that the shaping effect of zirconia medium is better than that of steel or alumina medium. With the zirconia balls with diameter of 6 mm and 8 mm in a mass ratio of 1∶1, rotation speed of 300 r/min, feed/ball mass ratio of 1∶3 and pulp volume fraction of 62.5%, the milling process results in the shaped sand with fineness of+0.15 mm 84.98% and flake granule accounting for 4.5%. The shaped machine-made sand has better compactness and angular characteristics, and it is qualified as the type I sand according to the standard GB/T 14684—2022, with better gradation and particle shape compared to the unshaped sand. The contour shape and angular characteristics of coarse granules can be greatly optimized than those of fine particles. It is concluded that under suitable conditions, a vertical bar stirring mill can obviously improve the shape of machine-made sand and optimize coarser grain composition.

With vanadium pentoxide and citric acid as raw materials, a kind of 3D flower-like VO₂(B) electrode material with large specific surface area and excellent structural stability was prepared by adopting hydrothermal synthesis. The crystal structure and morphology of the VO₂(B) electrode material were characterized by X-ray diffraction, scanning electron microscope, and transmission electron microscope, and the electrochemical properties of VO₂(B) electrode material were measured by constant current charge and discharge, as well as cyclic voltammetry. The results show that the first specific dischage capacity of 3D flower-like VO₂(B) electrode material is 227 mAh/g at a current density of 0.1 A/g. It delivers the first specific discharge capacity of 151 mAh/g at a high current density of 1 A/g, and retains 79.6% of this capacity after 300 charge-discharge cycles, exhibiting a good rate performance.

With the calcium-magnesium slag generated in recycling process of spent Li-ion batteries as raw material, battery-grade lithium carbonate was prepared by adopting a process consisting of leaching for decomposition, purification, lithium precipitation and carbonization for decomposition. The results show that with the addition of MgSO₄·7H₂O at 1.1 times of the theory amount, initial pH of 1.5, reaction time of 2.0 h, solid-liquid ratio of 1∶6, reaction temperature of 90 ℃, and final pH of 3.5, the leaching rate of Li can reach 98.39% and the mass concentration of Li in the lixivium is 18.03 g/L. Then, the obtained lixivium is subjected to processes of defluorination with resin, impurity removal with NaOH, and Na₂CO₃ precipitation, and crude lithium carbonate can be obtained with purity of 95.11%. By adopting a process consisting of carbonization, removal of calcium and magnesium with resin, and pyrolysis, a battery-grade lithium carbonate with purity of 99.64% can be prepared. It is shown that by using this processing technique, the lithium recovery rate can reach 95.08%, presenting good prospect in industrial application.