A mineral processing test was conducted to treat a low-grade rubidium-bearing lepidolite ore from Hunan Province with the grade of Li₂O and Rb₂O respectively at 0.27% and 0.17%. A flowsheet including a desulphurization and a lithium flotation was adopted, and an efficient collector CK was used in combination with dodecylamine to collect lithium minerals under weak alkaline conditions. In a closed-circuit test, a lithium concentrate was produced with Li₂O grade and recovery of 2.71% and 86.34%, Rb₂O grade and recovery of 1.02% and 51.24%, respectively. It is concluded that efficient utilization of low-grade lepidolite ore can be actualized.

A flotation experiment was conducted for a low-grade fine-grained cassiterite from Yunnan. The median dosage of reagent was determined by a single-factor test, and then the reagent dosage for rougher flotation process of cassiterite was optimized by response surface methodology as follows: 285 g/t of activator (KT-51), 13 g/t of inhibitor (OL-1C) and 873 g/t of compound collector (YK-Sn+SN-705). A verification test on flotation with the addition of those agents yielded a tin rougher concentrate grading 1.460% Sn at 74.44% recovery, which was close to the results predicted by response surface methodology. In order to further explore the effect, a closed-circuit test was conducted, resulting in the tin concentrate grading 5.45% Sn at 66.70% recovery. It is shown that efficient recovery of low-grade cassiterite resources can be actualized.

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%.

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.

Based on an introduction of the structural characteristics of single-crystal Ni-rich ternary cathode material, the common preparation techniques of such material are summarized. Besides, the main strategies for improving the performance of this material in recent years are also discussed, which can provide a reference for large-scale production of such high-performance single-crystal Ni-rich ternary cathode material.

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.

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.

With an increase in Ni content, the capacity of high-nickel layered metal oxides (LiNi_xMn_yCo_1-x-yO₂ (0.8≤x<1, NCM) greatly decreases. In view of such problem, it is proposed that singly-crystal NCM cathode material be modified by dual SiO₂@Li₂SiO₃ coating to improve its electrochemical performance. During the synthesis process, the reaction of can consume the residue lithium on the material surface, thus improving diffusion kinetics of interface lithium ions and inhibiting side reaction at the interface. It is shown that the modified cathode material delivers a specific discharge capacity of 156.88 mAh/g after 120 cycles, with capacity retention rate of 70.52%.

With the coal tailings from the flotation process of a coking coal preparation plant in Guizhou as the research object, the effects of four kinds of frother including methyl isobutyl methanol (MIBC), sec-octyl alcohol, terpenic oil and n-pentanol on the flotation performance of coal tailings were investigated. The test shows that the flotation indices of MIBC frother were better than those of the other three frothers with the similar dosage. A flotation process consisting of one stage of roughing, one stage of cleaning and one stage of scavenging was adopted to treat the raw coal with the ash content of 56.90%, and with dosages of kerosene and MIBC respectively at 1 000 g/t and 350 g/t, a qualified coking coal with the ash content of 11.47% and the yield of 32.03% can be produced. The results of foaming ability and foam stability measured by inflation method show that the foaming ability and foam stability of terpenic oil are the strongest, while those indices of n-pentanol are relatively weak, and those of MIBC and sec-octyl alcohol moderate. The characterization of the adhesion process between bubbles and coal particles under the action of different frothers analyzed with bubble-particle encapsulation angle and induction time measuring instrument suggests that MIBC can enhance coal-carrying capacity of bubbles, shorten particle-bubble induction time, thus bringing improved flotation effect.

In order to identify the feasibility of preparing alkaline pellets with low-quality magnesium-containing flux, experiments on pelletizing, preheating and roasting were carried out. Three kinds of magnesium-containing flux from Wulongquan Mine of WISCO Resources Group Co., Ltd., including interbedded dolomite, light-burnt material and lightburnt dolomite, were taken for pelletizing, and then effects of different magnesia flux and the adding amount on pelleting, as well as following preheating and roasting processes of alkaline pellet were all explored. The results show that the green ball prepared with the flux of interbedded dolomite presents superior performance. It is found that with alkalinity of 0.8, the green ball prepared with two different blending schemes have drop number of 4.1 and 6.6 respectively from height of 0.5 m, and compressive strength of 20.3 N/pellet and 22.3 N/pellet respectively. By increasing the addition of magnesia flux in two blending schemes, both preheated balls and roasted balls have their strength decreased after an initial improvement. With alkalinity between 0.6 and 0.8, the prepared pellet can have compressive strength of 2 620 N/pellet and 2 963 N/pellet respectively after preheating and roasting process. It is recommended that with interbedded dolomite and light-burnt material as magnesia flux, the alkaline magnesium-containing pellet prepared with alkalinity of 0.6-0.8 can meet industrial requirements.