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.

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°.

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.

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.

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.

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.

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.

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.

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.

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.