Based on the calculation theory of solid-liquid two-phase flow and consideration of collision effect, a hydrodynamic model was established by using VOF model, and reamer operation under different working conditions was also analyzed by numerical simulation. It is shown that a reamer working with an inclination angle of 45° can have a good effect, resulting in percentage of disturbed area at 68.32%. As the rotating speed of reamer increases, disturbance of the waters above a reamer gradually becomes violent, and the scope of waters being disturbed also gradually becomes wider first and then narrows down. It is concluded that a reamer should work with an inclination angle of 45°, rotate at a speed of 45 r/min and move laterally at a speed of 0.2 m/s, which can reduce disturbance to the waters brought by its operation, thus minimize the secondary pollution to the waters to a certain extent.

A shear creep test was performed for weak intercalation in order to investigate influence of creep characteristics of weak intercalation on slope stability. The obtained curve from the test was fitted according to Cvisc creep constitutive model, and the creep of slope with weak intercalation was calculated by using finite difference method to analyze the variation in long-term displacement and shear strain increment of the slope. The results show that the weak intercalation has typical creep characteristics. The results obtained from the numerical calculation with Cvisc model are basically consistent with the actual monitoring data. The creep characteristics of weak intercalation cause not only increase in the displacement, but also significant changes in the distribution form and orientation of the overall displacement of the slope, especially greater displacement at the top and in the middle of the slope. As a result, the slope body experiences an increment in the shear strain, which is then expanded and finally tends to stable.

In Bangzhong Zinc-Copper Mine in Tibet, a mining method consisting of stoping followed by backfilling is adopted to excavate ores. In order to further improve production efficiency and economic benefits in the mine, rock mass quality was classified based on the investigation of geoengineering and geomechanics and rock mechanics test, and key factors influencing stability of stopes were analyzed in combination with the layout of mining and cutting engineering. On this basis, stope structure parameters were optimized by using a variety of empirical stability charts. The results show that the improved stability chart is highly adaptable and a stop with span extended from 12.5 m to 20 m can still meet safety requirement in the mining production.

Based on an introduction of Japan's operation mechanism for exploiting deep-sea mineral resources, including Japan's marine policies, management and implementation agencies related to ocean mining, as well as Japan's coordination mechanisms for pushing progress in ocean technologies, Japan's cross-ministerial Strategic Innovation Promotion Program is outlined in terms of ocean mining, and the research achievements made by Japan in this field are also summarized. Such research on Japan's management system and program for exploitation of deep-sea mineral resources can be of reference for China in developing strategies, formulating investment mechanism and coordination mechanism for deep-sea mining.

With gold tailings as aggregate and ground gold mine tailings (referred to as gold mine tailings powder) as precursor materials, a kind of backfill material was prepared by alkali activation with sodium hydroxide together with sodium silicate as an activating agent. The effects of several factors, including particle size of gold mine tailings powder, modulus and addition of activating agent, on the mechanical properties of backfill mass were studied. The test results show that when gold mine tailings is ground for 60 min (size d₅₀ of 5.939 μm), modulus and addition of sodium silicate in activating agent are 1.2 and 60% respectively, the prepared backfill mass can have a 28 d compressive strength of 854.2 kPa, completely up to the requirement for backfill mass stipulated in the GB/T 39489—2020 "Technical Specification for Paste Filling with Total Tailings". Due to alkali activation, gold mine tailings powder is subjected to a hydration reaction, yielding a large amount of aluminosilicate gel, which forms a dense and stable structure, resulting in the backfill mass with good mechanical properties.

In order to define a mutual disturbance range between the upper and lower ore belts of a copper-gold mine during 8-year co-mining period, a deformation law of stratum by natural caving mining method is summarized based on the characteristics of stratum movement and deformation induced by mining. Combined with the actual mining technologies on site, a law of rock movement is explored for the lower ore belt by adopting engineering analogy method, theoretical calculation method and numerical simulation method, and the critical mining-induced disturbance range is defined to ensure safe mining of the upper ore belt, which provides a basis for the planning and layout for the mining of the lower ore belt. It is found that for safe mining of the upper ore belt, the lower ore belt should have security pillars of about 550 m along the strike, with the minimum angle of stratum movement within the range from 70° to 73.3°.

Based on the environmental characteristics of polymetallic nodules mining zone, different lifting modes for deep-sea polymetallic nodules, including continuous line bucket (CLB) system, autonomous submersible shuttle mining system and pipeline lifting system, were analyzed in terms of characteristics and applicability. With eight factors taken into consideration, including maneuverability, dry ore lifting capacity, launching and recovery efficiency, manufacturing and operation costs, suitability for water depth, adaptability to extreme sea condition and seabed disturbance, as well as environmental friendliness, a mathematical model covering multi-dimensional evaluation indices and an adaptability evaluation system were established. Analysis results show that CLB system and capsule pipeline lift system are not suitable for lifting polymetallic nodules, while autonomous submersible shuttle mining system, due to high cost in R & D, is not economically applicable. Due to the improvement in the reliability of underwater equipment and progress in the solution to sealing of heavy medium, pipeline lift system with heavy medium is expected to become a high-efficient lifting mode for deep-sea polymetallic nodules.

In order to accurately evaluate stability of surrounding rock of roadway with weak intercalation, an improved analytic hierarchy process and criteria importance through inter-criteria correlation (CRITIC) method, were adopted to determine comprehensive weight, and unascertained measure theory (UM) was used to determine unascertained measurement vector. Furthermore, the set pair analysis theory (SPA) was introduced to optimize confidence evaluation process, and then a UM-SPA coupling analysis model was established and used to evaluate the stability of surrounding rock of the roadway with weak intercalation in some gold mine. The results show that in-situ stress, tensile strength and thickness of weak intercalation are the main factors influencing the stability of such kind of roadway. The set pair potentials of sections D4, D5, D6, D7, and D9 belong to micro-reversal potential and tend to be unsafe. The stability of roadway at different levels is in the following descending order: 290^# level > 150^# level > 90^# level. The practical verification has proven that this model has an evaluation result consistent with the actual situation.

In order to improve the effect of deep-hole bench blasting in open-pit mines, a buffer blasting technique was proposed based on the on-site investigation of existing bench blasting parameters and rock fragmentation. In combination with simulation study by using LS-DYNA software and theoretical calculation, optimal borehole parameters and buffer thickness were finally determined, which were applied into the field blasting experiment. With buffer thickness of 5 m, borehole spacing of 5 m and burden of 4 m, the field blasting experiment brought an average fragmentation of less than 7%, showing a good blasting effect.

With support vector machine (SVM) optimized by whale optimization algorithm (WOA), a WOA-SVM hybrid model was established for predicting blasting vibration. Then, with root mean squared error and coefficient of determination as evaluation indices of the model, WOA-SVM model, SVM mode, Sadovsky's model and USBM model were compared based on the data of blasting vibration in Sijiaying Iron Mine. A comprehensive evaluation shows that the WOA-SVM model is superior to other models in terms of prediction accuracy.

The adsorption mechanism of La³⁺ and NH₄⁺ ions on (001) and (00-1) planes of kaolinite has been studied based on the first-principle calculation of plane-wave pseudopotentials of density functional theory. The results show that La³⁺ ions are mainly adsorbed on kaolinite surface through electrostatic interaction, while NH₄⁺ ions are adsorbed thereon through both electrostatic interaction and hydrogen bonding, with more electrons transferred onto kaolinite surface than La³⁺. The absolute values of adsorption energy for ions on (001) plane of kaolinite are in the following descending order: La³⁺ > NH₄⁺ > H₂O, while on (00-1) plane in the following descending order: NH₄⁺ > La³⁺ > H₂O. It is found that La³⁺ ions are prone to be adsorbed on (001) plane, while NH₄⁺ ions are prone to be adsorbed on (00-1) plane. When ammonium sulfate is used as a leaching agent, rare earth ions like La³⁺ adsorbed on the (001) plane can only be effectively displaced with the leaching agent at a certain concentration.

A commercially applied large ball mill with an effective internal diameter of 4.6 m is taken for study, and the discrete element method (DEM) was introduced to simulate and investigate the influence of filling rate of grinding media (steel balls) on the collision of particles inside the mill and energy consumption. It is found that when the filling rate of grinding media is 30% - 35%, the frequency of ball-ore collision increases gradually. However, the ratio of ore-ore collision frequency to the total collision frequency increases first and then decreases, and the energy loss for ball-ball and ball-liner collisions increases. It can be seen that increasing filling rate of grinding media may not only reduce grinding efficiency and increase energy loss, but also increase liner wear by steel ball, which is not conducive to sustainable usage of mill liner.

In order to explore the influence of ultrafine grinding using high-pressure grinding roller (HPGR) on the separation performance of copper-bearing iron ore, mineral separation tests were carried out for HPGR milled ore. The results show that HPGR products are usually smaller and more uniform in size compared to jaw crushing products. Furthermore, obvious grain boundary cracks in HPGR products can be observed. Based on the comparison with jaw crushed ore, a test on magnetic separation of HPGR milled ore for tailings discarding led to the obtained product with iron grade up by 0.4 percentage points and iron recovery down by 0.8 percentage points, while both copper grade and recovery up by 0.01 and 2.11 percentage points respectively. A flotation test resulted in the roughing concentrate with copper grade and recovery up by 0.21 percentage points and 1.84 percentage points, respectively. The following magnetic separation test of the obtained roughing tailings led to the final iron concentrate with grade and recovery up by 1.11 and 2.45 percentage points, respectively. It is concluded that compared with jaw crushing, HPGR grinding is more conducive to improving copper grade and recovery of iron concentrate.

A barite ore from Guizhou province is a typical microfine refractory carbon-containing ore with uneven grain size distribution and complex dissemination relationship among barite and gangue minerals. After being milled to a grinding fineness of -0.075 mm 90%, the ore was processed using kerosene and terpenic oil for decarburization, with sodium carbonate as the pH regulator, sodium silicate as the depressant and CY-30 as the collector for barite flotation. A close-circuit flotation test yielded 75.92% barite concentrate grading 93.55% BaSO₄ at 87.85% recovery.

The predominant minerals in a kind of high siliceous non ferrous metal tailings include quartz, alunite, dickite, sericite and pyrite. The quartz has relatively coarser grain size, while alumite and dickite are enriched in a relatively finer fraction. Furthermore, alunite, quartz, dickite and sericite minerals are complicatedly disseminated. Herein, tests were conducted to reclaim alunite and quartz therefrom. An alunite concentrate with SO₃ grade of 20.14% can be obtained by using a process consisting of desliming, desulfurization and alunite flotation. And then, the obtained alunite flotation tailings are subjected to a reverse flotation, yielding a quartz concentrate grading 96.38% SiO_2. It is shown that this flowsheet can actualize an efficient and comprehensive utilization of nonferrous metal tailings.

Flotation tests were conducted for a complex refractory copper-lead-zinc polymetallic sulfide ore bearing arsenic and silver. By using a new high-efficient sulfide ore collector (CYC) and an environment friendly lead depressant (CYZ), the test with a flowsheet consisting of rough grinding, copper-lead-silver bulk flotation, classification and regrinding, reagent removal and Cu/Pb separation produced a copper concentrate grading 22.42% Cu and 11 549.74 g/t Ag with corresponding recoveries of 73.77% Cu and 83.85% Ag, as well as a lead concentrate grading 13.96% Pb and 6.61% Sb with corresponding recoveries of 19.45% Pb and 11.10% Sb. It is shown that with this technique, an efficient Cu/Pb separation can be actualized, while the associated Ag and Sb minerals can also be reclaimed effectively.

Due to high oxidation rate of a lead-zinc sulfide ore, the on-site flotation practice presented poor beneficiation indices. In view of this problem, an optimized closed-circuit process consisting of two stages of roughing, two stages of scavenging, one stage of rough cleaning of combined roughing concentrates, two stages of cleaning and two stages of scavenging for roughing concentrates was proposed. With slime (800 g/t) and CD-2 (300 g/t) as pyrite depressants, CD-1 (600 g/t) and water glass (600 g/t) as gangue depressants, sodium sulfide (500 g/t) as a sulfiding agent, copper sulfate (500 g/t) as an activator, butyl xanthate (200 g/t) as a collector, and terpineol oil (21 g/t) as a foaming agent, a closed-circuit flotation test produced a bulk concentrate grading 16.25% Pb and 27.69% Zn with a lead recovery of 65.05% and a zinc recovery of 92.49%. Compared with the previous on-site flowsheet, the Pb grade and Pb recovery are improved by 2.24 percentage points and 9.36 percentage points, while Zn grade and Zn recovery up by 1.57 percentage points and 5.14 percentage points respectively.

A flotation experimental study was conducted to process a copper sulfide ore. A closed-circuit flowsheet consisting of copper preferential flotation and sulfur recovering from copper flotation tailings was adopted, resulting in a copper concentrate grading 23.01% Cu at 95.47% recovery and a sulfur concentrate grading 35.72% S at 58.48% recovery.

Flotation tests were carried out for a low-grade complex copper ore from Hubei province. The influences of grinding fineness, reagent type and dosage on flotation indices were investigated. A closed-circuit flotation flowsheet consisting of one stage of roughing, three stages of cleaning and three stages of scavenging was adopted to process this kind of ore with Cu grade of feed ore of 0.42%, grinding fineness of -0.074 mm 75.2%, butyl xanthate combined with Z-200 and sodium diethyldithiocarbamate as collectors, calcium hypochlorite combined with lime as regulator. As a result, a copper concentrate with Cu grade of 12.15% and recovery of 85.05% was recovered.

In order to solve the problem of high water content in JISCO iron concentrate, dewatering tests were conducted by adding filtration aid. The results show that the filtration aid, CYG-1, can improve filtration effect. With the addition of CYG-1 at an amount of 500 g/t, the water content in the filter cake of iron concentrate falls by 2.31 percentage points compared to the practice without adding filtration aid.

Based on computational fluid dynamics (CFD) method, a multiphase VOF model and Realizable k-εturbulence model were used to simulate flow characteristics of a large bottom-blown furnace with different blowing modes, and analyze a pre-stabilization process, motion characteristics of blown gas, gas-matte-slag interaction characteristics and mixing effect in molten pool. The results show that the large bottom-blown furnace has two oxygen lances for blowing, which can altogether generate an enhanced pneumatic agitation zone, resulting in a remarkable gas-matte-slag interaction in the furnace, thus providing good dynamic condition for the large bottom-blown furnace. The furnace with double lances blowing at an angle of 9° can bring a better agitation effect, leading to the gas content at a rate of 2.70%, average speed of 0.20 m/s and average turbulence energy of 0.059 m²/s² in the molten pool. There is severe internal disturbance and less splashing of melt in the molten pool, which is beneficial to improving smelting efficiency.

A process consisting of direct reduction roasting and magnetic separation was adopted to separate and recover iron and titanium from ilmenite rough concentrate. A single factor experiment was conducted to explore effects of several factors, including reduction temperature, reduction time, coal powder dosage, borax dosage, bentonite dosage, grinding fineness, and magnetic field intensity, on the grades and recovery of iron concentrate and titanium concentrate. Then, the optimal processing parameters were finally determined. A reduction roasting runs at 1 200 ℃ for 2 h by adding coal powder at an amount of 40%, borax at 2% and bentonite at 2%, with a grinding fineness of 84% -38 μm, followed by a magnetic separation with field intensity of 79.62 kA/m, resulting in an iron concentrate grading 82.57% Fe at 83.59% recovery, and a titanium concentrate approaching 49.23% Ti grade at 85.18% recovery. It is shown that good beneficiation and smelting indicators are obtained.

After an in-situ leaching of weathered crust elution-deposited rare earth ores with ammonium sulfate, the obtained tailings were taken to explore the variation of water content, pH value, Zeta potential with sampling depth, and then the total nitrogen content, nitric nitrogen, ammonium nitrogen and the main co-existing ions were also analyzed. The results indicate that the tailings samples were all acidic, and both water content and Zeta potential decreased with increasing of sampling depth. The residual ammonium salt in the ore body mainly exists in the form of water-soluble ammonium (11%-33%), and ion-exchange ammonium (59%-87%) in ammonium nitrogen, presenting the highest content in middle layer and the lowest content in surface layer. XRD analysis reveals that the content of clay minerals in the rare earth tailings positively correlated with the content of residual ammonium. In addition, high content of organic matter in the surface layer of the ore body leads to the highest content of co-existing cations Al³⁺ and RE³⁺ in the surface layer; while as for the ore body at deeper position, the content of co-existing cations Al³⁺ and RE³⁺ decreases obviously, and the co-existing anions SO₄^2- and Cl^- present an opposite variation trend.

An efficient defluorination agent (NY-Z02) was used to remove fluoride from high-salt fluoride-containing wastewater generated in the process of recycling spent batteries. The effects of pH value, reaction temperature, reaction time and dosage of defluorination agent on fluoride removal effect were investigated. On this basis, a two-stage fluoride removal process was put forward, with which a pilot test was carried out. Results show that by using a single-stage fluoride removal process, a reaction runs at 20 ℃ for 20 min with pH of 7.0 at the end and by adding defluorination agent at an amount of 1.2%, resulting in the fluoride concentration in the wastewater decreased to 12.5 mg/L. While by using a two-stage fluoride removal process, with addition of defluorination agent at an amount of 1.0%, the fluoride concentration in the wastewater can be decreased to 12.4 mg/L. In the pilot test with the dosage of defluorination agent reduced to 0.768%, the fluoride concentration in the wastewater after fluoride removal process met the requirement of enterprise (F≤20 mg/L). It is found that during the removal process with agent NY-Z02, fluoride ions in wastewater react with the agent and form precipitate of AlF₃, or together with Al (OH)₃ are removed by flocculation and precipitation. It is shown that this process has good fluoride removal effect without bringing in any impurities.

Blown zinc powder, electric furnace zinc powder, zinc alloy powder and distilled zinc powder were respectively taken in the test of cobalt removal by arsenic trioxide purification process to investigate influences of several factors on cobalt removal effect, including an adding amount of zinc powder, temperature and time of reaction, a mole ratio of copper to cobalt and a mole ratio of antimony to cobalt. Results show that when copper sulfate is added with copper and cobalt in a mole ratio of 5.0, potassium antimony tartrate is added with antimony and cobalt in a mole ratio of 0.5, a reaction at 90 ℃ for 90 min, with rotation speed of 300 r/min and addition of zinc powder at an amount of 2 g/L, the cobalt removal rates by using 4 different kinds of zinc powder are 95.73%, 96.15%, 95.94% and 94.87%, respectively, indicating the cobalt removal effect of different powder in the following descending order: electric furnace zinc powder > zinc alloy powder > blown zinc powder > distilled zinc powder.

Base on the study on homogenization behavior of blast furnace slag (BFS) by dynamic viscosity experiment, a kinetic model was constructed for molten slag conditioning process. The homogenization state of BFS was verified and the final granulation effect was analyzed. It is found that the homogenization time becomes shorten first and then prolonged as the addition of conditioner increases, which is the shortest when an addition of conditioner is at an amount of 15.43%. As for BFS with grain size greater than 1.75 mm, the homogenization time increases obviously. As slag temperature increases, the homogenization time is gradually shortened. Based on the comparison with the composition and mineral phases of fully homogenized BFS, it is verified that homogenization is completed when viscosity value becomes stable. The granulated slag particles with size mainly in the range from 1 mm to 2.5 mm present approximately normal distribution, and the homogenized BFS has amorphous phase content higher than 85%, meeting the requirements in the national standard.

In order to achieve utilization of antimony and alkali in arsenic-alkali slag and solidification of arsenic, a new processing technique, consisting of separation antimony by water leaching, arsenic precipitation by hydrothermal reaction with lime, and alkali extraction by evaporation, was proposed to treat arsenic-alkali slag. Results show that water leaching at 90 ℃ for 5 h with liquid-solid ratio of 3∶1 can result in the leaching rate of arsenic up to 97.96% and the leaching rate of antimony just 0.72%. The obtained leaching residue only contains 0.09% arsenic, presenting effective separation between antimony and arsenic. With calcium and arsenic in a molar ratio of 1.43, hydrothermal reaction at 170 ℃ for 2 h can lead to an arsenic precipitation rate up to 99.68% and the solution after precipitation with arsenic and alkali in a mass ratio of 1.65‰, also presenting a good separation effect. Finally, the concentration and crystallization process by evaporation can generate crystalized alkali containing only 0.14‰ arsenic, which can meet the technical requirement for alkali in antimony refining.

With Ca (NO₃)₂·4H₂O and Al (NO₃)₃·9H₂O as raw materials and urea as precipitant, a precursor Ca-Al-LDHs was prepared by microwave heating and hydrothermal synthesis. A product of Ca-Al hydrotalcite (Ca-Al-LDOs) was obtained after roasting, and it was used to adsorb fluorine in wastewater. It is found that Ca-Al-LDOs are of typical layered structure similar to hydrotalcite. With pH of 2, initial concentration of F^- ion at 500 mg/g, adsorbent dosage of 2.5 g/L and reaction time of 180 min, the adsorption capacity reaches 173.9 mg/g and the removal rate of fluorine reaches 92.01%. It is found that the process of adsorption conforms to the Freundlich adsorption isotherm mode, and its kinetics conforms to the quasi-second-order kinetic model. The adsorbent Ca-Al-LDOs can be reused after desorption, with defluorination rate keeping at 68.92% after 8 cycles of regeneration.

A technique process to remove impurities of calcium and magnesium from the leaching solution obtained after roasting plus leaching process of a sort of lepidolite was studied, and the effects of several factors on washing effect, including amount of sodium carbonate, solution pH, time and temperature of reaction and washing conditions, were all investigated. The results show that removal rates of calcium and magnesium can reach 99.9% and 93.1%, respectively, by adding sodium carbonate as precipitant at an amount of 2.21 mol/L, with pH of solution at 8.0, temperature of 25 ℃and time of 30 min. Then, the obtained calcium-magnesium residue was washed three times with a liquid-solid ratio of 1∶1, and 5 min for each time. As a result, products of calcium carbonate and magnesium carbonate can be obtained. It is concluded that this process, being simple and stable, can be adopted to effectively remove impurities of calcium and magnesium from leaching solution of lepidolite.

A micro- and nano-indentation test was performed for CoCrFeNiMn high entropy alloy. The relationship between the geometrically necessary dislocation (GND) density of CoCrFeNiMn and reciprocal value of real indentation depth (1/h) was obtained under different working conditions, and the influence of elastic factor (Δe) on GND density was also explored. The results show that GND density with the consideration of elastic deformation (ρ_Ge) presents a nonlinear relationship with 1/h, while GND density without the consideration of influence of elastic deformation (ρ_G) has a linear relation with 1/h. Based on the comparison of variation of ρ_G/ρ_Ge with the indentation depth, it is found that the ratio of ρ_G/ρ_Ge is 3-4 when the indentation depth is less than 500 nm, indicating that elastic factor can have an obvious impact on the GND density at shallow indentation. And, the ratio of ρ_G/ρ_Ge is approaching 1 when the indentation depth is up to 3 000 nm. It is shown that as indentation depth increases, dislocation slip gradually dominates deformation.

The out-of-life saggar after repeated use for LiCoO₂ sintering in industry was taken to explore its erosion mechanism during high temperature synthesis of LiCoO₂ by adopting fluorescence analysis, chemical composition analysis, X-ray diffraction analysis, microstructure and energy spectrum analysis. Results show that when saggar is used to hold basic cobalt carbonate and lithium carbonate and calcined at 950 ℃ for 15 h, it is eroded and damaged after 15 times of operation. During LiCoO₂ synthesis, saggar is mainly eroded by lithium ions, with the dominant erosion products including tetragonal LiAlO_2, α-LiAlO_2, LiAlSiO_4, Li₃AlSiO₅ and Li_3.17Si_0.7S_0.3O_4. Cobalt ions are not involved in the chemical erosion but the synthesized lithium cobalt compounds migrate along the pores and also deposit along the migrating pores of saggar.

A kind of flake graphite with grain size D₅₀ of 40.3 μm from Inner Mongolia was taken in a spherification test by adopting a QCJ vortex micropulverizer, and two kinds of spherical products with D₅₀ of 16.42 μm and 11.68 μm respectively were obtained, of which the corresponding tapped density increased from 0.46 g/cm³ to 0.95 g/cm³ and 0.80 g/cm³ respectively, presenting a total spherification rate of 50.48%. The spherical products were purified with mixed acid, with the fixed carbon content therein up to 99.95% and 99.97% respectively, and then the electrochemical performance of the products was tested. The anode material with those two products delivered initial discharge specific capacities of 366.60 mAh/g and 364.30 mAh/g, respectively, and presented initial charge-discharge efficiency of 93.40% and 92.32%, respectively. It is shown that the capacity retention rate can exceed 99% after 30 cycles at 0.1C current.

20CrMnTi alloy steel was precisely cut by turning instead of grinding using a polycrystalline cubic boron nitride (PCBN) tool. Based on analysis of the form and mechanism of PCBN tool wear during the cutting process, the influences of different cutting parameters on tool life and surface roughness of workpiece were studied. The results show that the tool is subjected to diffusion, chipping and severe oxidative wear. Among those three elements of hard material cutting, both feed rate and cutting speed bring great influence to tool wear, and feed rate has great influence on the surface roughness of machined workpiece.

Experiments of erosion corrosion with 3.5% NaCl solution at different flow rates were performed for TP2 copper after different heat treatment (hard and soft states), and the erosion corrosion rates of TP2 copper were tested. The morphology and products after 240 hours of corrosion were characterized, and the mechanism of erosion and corrosion for TP2 copper was also discussed. The results show that flowing medium in corrosion test accelerates the corrosion rate of TP2 copper. The soft TP2 copper presents a higher corrosion rate, compared to hard TP2 copper, after 240 hours of corrosion at the same flow rate. And after 240 hours of erosion corrosion at a higher flow rate, TP2 copper has its surface morphology predominated by gully-like structure and a product of Cu₂O is generated after corrosion.

Based on the relevant patents of layered cathode materials for sodium-ion batteries in China, a review of patent applications (authorization) is presented in terms of annual trend and main applicants. Also, some representative patents on precursors, structure, chemical washing and coating of layered cathode materials for sodium-ion batteries are chosen for analysis, Finally, the industry development trend, as well as technical difficulties and hotspot in this industry are summarized.

Activated carbon derived from coconut shell was prepared as anode material by adopting high temperature pyrolysis and activation. The effects of activation on the structure, morphology and electrochemical properties of coconut shell carbon were investigated by using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The results show that the coconut shell carbon after activation process is highly disordered, and also microporous and mesoporous. It delivers an initial discharge specific capacity of 918.22 mAh/g at a current density of 0.1 A/g, and retains a specific capacity of 447 mAh/g after 200 cycles discharge at a current density of 1 A/g.

The advantages and disadvantages of several technologies for recycling spent LiFePO₄ batteries, including pre-treatment, hydrometallurgical process, and direct regeneration and repairing, were presented in terms of recovery efficiency, economic and environmental benefits, and commercial feasibility. The development trend of each technology is also analyzed. All these can serve as reference for optimizing and improving the technologies to recycle spent LiFePO₄ batteries in the future.

For evaluating vibration reliability of Li-ion battery packs used in heavy-duty mining vehicles, ANSYS, finite element software, was adopted to simulate Li-ion battery packs in a heavy-duty mining vehicle and calculate its stochastic vibration. Based on the test performed about random vibration of battery packs, it is found that the first modal frequency of the battery packs is 33.85 Hz, corresponding to the frequency of upper cover of battery packs, which is greater than the external excitation frequency transmitted by frame (30 Hz). thus low-order frequency resonance can be avoided and vibration reliability of the structure can be improved. The calculated stresses in the random vibration of key parts of battery packs, including stiffener, lower box, upper cover and battery brackets, are all lower than the yield strength of the corresponding materials, indicating the structural parts of battery packs meet the requirements for strength reliability. Permanent deformation and damage have not been found in the assembly of battery packs in the random vibration test, verifying the reliability of this simulative computation results.

Based on an analysis of a trend in global patent application and distribution of patented technologies for second life power batteries, as well as a discussion on the global competition situation and hotspots in R & D of technologies in this industry, the relevant patent application situation in China is analyzed. It is found that the number of applications for patents on second life power batteries in various countries is steadily increasing, and there is still room for improvement. The classification, detection, screening, and evaluation of retired power batteries have always been the hotspots in technical R & D and are still in development, for which the patent applications present stable upward trend. China, as a major source of relevant technologies, has been playing an important role in patent portfolio, which is consistent with global development trends. The applications for patents on relevant technologies are still expected to increase in the future. Therefore, it is recommended that relevant enterprises should intensify their efforts in R & D to seize opportunities in the industry, and also improve the patent portfolio.

Based on an introduction of the background and operational effectiveness of the Central Geological Exploration Fund, the important role of the fund in mineral exploration and its profound significance to the market-oriented reform of the geological exploration industry are elaborated. Then, the main problems to be solved urgently are analyzed based on the implementation of the fund project. Some thoughts for promoting reform of the fund are finally put forward in consideration of the current development of the mining sector, actual situation of state finance, as well as the characteristics of the Central Geological Exploration Fund.