A kind of low-impurity lead electrolyte was prepared with lead ingots, fluorosilicic acid, hydrogen peroxide, bone glue, and β-naphthol as raw materials, and then was used in an experimental research on 14 consecutive cycles of electrolysis to produce refined lead. It is shown that the initial power consumption of lead electrolysis was 52.37 kW·h/t, and 6N high-purity lead was produced in the first two cycles; as the cyclic electrolysis process proceeded, the impurity content and lead ion content in the electrolyte gradually increased, while the mass concentration of fluorosilicic acid gradually decreased, resulting in an increase in the impurity content of precipitated lead. Therefore, the content of Cu, Ag, Fe, Al and other impurities in the precipitated lead all gradually increased after two cycles of electrolysis, and the precipitated lead met the standard for 5N but did not meet the standard for 6N high-purity lead. Furthermore, the power consumption also gradually increased, but remained at a low level of 50 kW·h/t to 70 kW·h/t for each cycle.

To improve the interfacial stability of spinel phase LiNi_0.5Mn_1.5O₄ cathode material in deeply charged state, a nanoscale Al₂O₃ film was deposited on the surface of single-crystal LiNi_0.5Mn_1.5O₄ by atomic layer deposition in a controlled manner. The modified cathode material exhibits excellent long-cycle performance and corrosion resistance (with capacity retention rate up to 94.7% after 500 cycles at 1C). The surface and interface analysis shows that the nanoscale Al₂O₃ coating deposited by atomic layer deposition technology can significantly inhibit the corrosion reaction between material and electrolyte, and also constrain the irreversible dissolution and precipitation of transition metal ions. In addition, AlF₃ produced by HF surface etching can enhance corrosion resistance of LiNi_0.5Mn_1.5O₄ cathode material, which can thus improve its long-cycle performance and the service performance at high voltage.

A method of selective adsorption and recovery of gold from waste thiourea liquid with biomass-based adsorbent prepared from phyllostachys pubescens was proposed. The charcoal, after being activated in H₂O-CO₂ atmosphere, has more nanopores with smaller size on its surface, compared to being activated by CO₂ alone, which greatly increases the specific surface area of the adsorbent material. Based on exploration of the effects of factors, including type of adsorbent material, pH value, adsorbent dosage, adsorption temperature, and adsorption time, on the adsorption of gold in waste thiourea liquid, the appropriate adsorption conditions were obtained as follows: pH of 6, adsorbent dosage of 8 g/L, adsorption temperature of 25 ℃, and adsorption time of 3.5 h. It is found that activation in H₂O-CO₂ can bring the activated carbon with better adsorption effect, and the removal rate of gold from waste thiourea liquid by adsorption can exceed 96%. The adsorption isothermal model is used to fit the process of gold adsorption from waste thiourea liquid by the carbon activated in H₂O-CO₂ atmosphere, and the results show that such gold adsorption process follows Freundlich model and is a physical adsorption process.

An experiment was conducted on selective extraction of lithium by co-pyrolysis of spent NCM cathode powder and polypropylene followed by water leaching, and the obtained pyrolysis products were characterized. In the experiment, co-pyrolysis of NCM cathode powder with 40% polypropylene ran at 550 ℃ for 2 h, with argon flow rate at 200 mL/min, and then the obtained pyrolysis product was subjected to water leaching, resulting in the lithium leaching rate of 87.92%. It is found that lithium loss is mainly attributed to the formation of water-insoluble lithium cobalt oxide during co-pyrolysis.

A low-grade high-sulfur copper ore from Anhui Province has a sulfur grade of 41.30% and a copper grade of 0.53%. It is difficult to control the flotation index of this easy-to-oxidize ore. To improve the Cu/S separation effect, the influence of grinding fineness, reagent type and reagent dosage on copper flotation index was investigated. A closed-circuitflotation process including one stage of roughing, two stages of cleaning and two stages of scavenging was adopted to treat the ore with a grinding fineness of 83.88% -0.074 mm, with CaO and Na₂S as a combined depressant, Z-200 as the collector and terpenic oil as the frother. It is found that a copper concentrate grading 15.27% Cu at 80.96% recovery can be obtained. This experimental study can provide a reference for flotation separation of copper from low-grade high-sulfur copper ore.

Sn-Sb-Cu-Fe-Zn high-entropy alloy nanoparticles were uniformly anchored on conductive interconnected carbon nanofibers by electrospinning in combination with calcination process, and a composite anode material of SnSbCuFeZn@CNFs for lithium-ion batteries was successfully synthesized. Research shows that calcination temperature has an important influence on the phase composition and morphology characteristics of the synthesized material, and directly affects the crystal phase, size and distribution of Sn-Sb-Cu-Fe-Zn high-entropy alloy nanoparticles, also determines the electrochemical performance of SnSbCuFeZn@CNFs electrode. In the studied samples, the SnSbCuFeZn@CNFs-900 electrode can present excellent comprehensive performance: it delivers an initial specific discharge capacity of 1 232.8 mA/g at 0.1 A/g, and has reversible specific discharge capacity retaining at 786.0 mA/g after 200 cycles; it delivers a specific discharge capacity of 433.8 mA/g after 500 cycles at 1.0 A/g; it is found that the pseudo-capacitance accounts for as high as 93.37% at a scanning speed of 2.0 mV/s.

In order to explore influence of the thickness of barrier pillars reserved in stopes on mining operation during the transition from mining with caving to mining with backfilling in a copper-zinc mine in northwest China, six thickness schemes were selected for the barrier pillars in the stope based on the mining status and the engineering geological conditions. Then, a three-dimensional numerical model was constructed with 3Dmine-Rhinoceros, and factor of safety and zone safety were adopted in the analysis. As for the mind-out area without backfilling in the middle section of upper part, three continuous stope interval mining on the level of 210 m was calculated based on simulation with FLAC^3D, and the changes in roof settlement deformation, factor of safety and zone safety were also analyzed for the barrier pillars left with different thickness after mining. It is found that with the barrier pillars of 12 m in thickness, the stability of stope can be ensured during transition of mining. Thus, it is recommended that the thickness of reserved barrier pillars be no less than 12 m.

TiO₂ was coated on the surface of LiMn₂O₄ by thermal decomposition of titanate coupling agent, and the effects of coating treatment on the structure and electrochemical performance of LiMn₂O₄, as well as material structure in the cycling were all explored. The results show that TiO₂ can be uniformly coated on the surface of the LiMn₂O₄ by thermal decomposition of titanate coupling agent at 550 ℃. Surface coating does not change the crystal structure of LiMn₂O₄, but obviously improves its electrochemical performance, especially high temperature rate performance and cycle performance. At 55 ℃, LiMn₂O₄ with TiO₂ coating delivers a specific capacity of 75.34 mAh/g at 5C, which is higher than that without coating (43.05 mAh/g). After 150 cycles, the capacity retention rate of the material with TiO₂ coating and without coating is 77.27% and 62.85%, respectively. The improvement of electrochemical performance is attributed to reduction of Mn dissolution in the cathode material by TiO₂ coating, which thus inhibits the change of crystal structure during cycling process, reduces the electrode polarization and charge transfer impedance, as well as improves the charge-discharge reversibility of the material and the Li⁺ diffusion.

In order to explore the formation mechanism of landslides and reveal the development process of landslides, Mayang Miao Autonomous County in Hunan Province was taken as an example, and landslide analysis was conducted for red beds area in Hunan Province based on susceptibility to the selected factors causing disasters, including elevation, slope, terrain ruggedness index (TRI), stratum lithology and distance away from faults, among others. It is found that landslide occurrence is well correlated with several factors, with susceptibility to each factors in the following descending order: type of land use>elevation > TRI > normalized difference vegetation index (NDVI) > distance away from roads > slope > stratum lithology > distance away from rivers > average rainfall during recent several years > distance away from fault, and the corresponding factors with high sensitivity are listed as follows: land used for buildings, elevation [101 m, 1 394 m), TRI[47 m, 74 m) and NDVI[0.30, 0.43).

With a flake graphite ore from Africa as the raw material, a beneficiation technique was adopted to recover graphite resource according to ore size fraction. The results show that the fixed carbon content of the graphite feed ore is 32.54%, and the large flake graphite mainly in sheet or banded structure is intergrown with feldspar minerals. The optimized roughing condition is determined as follows: grinding fineness of -0.074 mm 72.87%, kerosene dosage of 50 g/t and terpineol dosage of 150 g/t. A flotation process with one stage of roughing, one stage of scavenging and four stages of cleaning is adopted, in which the large flake graphite is screened from the flotation production of the 1st-stage of cleaning, while the undersize is treated further by three stages of grinding and three stages of cleaning to recover fine flake graphite. The closed-circuit test shows that the fixed carbon content in the large flake graphite (+0.150 mm) concentrate and the fine flake graphite (-0.150 mm) concentrate reaches 96.53% and 96.21%, respectively. The recovery rate of the large flake graphite reaches 22.74%, which is higher by 7.66 percentage points compared to that by conventional regrinding-separation approach.