A cyanide-free leaching test was performed for the arsenic-carbon bearing gold ore from Laos, and effects of grinding fineness, pH value of pulp, concentration of slurry, and the dosage of golden cicadas environment-friendly leaching agent for gold on gold leaching effect were investigated. The results show that pre-treatment with hydrogen peroxide can improve the leaching rate of gold. With a grinding fineness of -0.074 mm 95% and an agitating speed of 2 000 r/min, the pulp is pre-oxidized with 500 g/t of hydrogen peroxide for 3 h, and then treated by 30 h agitation leaching with addition of lime at an amount of 3 000 g/t and golden cicadas environment-friendly leaching agent for gold at 5 000 g/t, leading to the residue grading 0.25 g/t Au and gold leaching rate of 92.27%. It is shown that this pretreatment with hydrogen peroxide can make gold leaching rate up by 1.96 percentage points.

Vanadium was extracted from vanadium-containing stone coal by adopting a process of sulphuric acid curing and water leaching, and the effects of sulphuric acid curing and water leaching conditions on vanadium leaching rate were investigated. It is found that the vanadium-containing stone coal is firstly subjected to a sulphuric acid curing process at 130 ℃ for 8 h, with an addition of H₂SO₄ at an amount of 25%；and then the obtained product is leached by water at 90 ℃ for 120 min, with liquid-solid ratio of 2∶1, resulting in the vanadium leaching rate of 90.79%. After the vanadium-containing leachate is oxidized with NaClO₃, the vanadium in the oxidized solution is adsorbed with D202, and then the vanadium in the resin is desorbed. The obtained solution after desorption is subjected to calcination, and vanadium pentoxide is produced with a purity up to 99.21%. It is shown that a total recovery rate of vanadium is 85.99%.

In order to know the status quo of technologies for deep-sea mineral resources development, the related patents were briefly analyzed. A total of 3 236 patents regarding deep-sea mineral resources development technologies published worldwide from 2000 to 2023 were taken from the incopat global patent database, and analyzed in terms of number of patent applications, geological distribution, subdivision of technologies, time of Chinese patents applications, as well as nationalities of Chinese patent applicants among others. It is found that the patents regarding deep-sea mineral resources development are mainly from China, United States, Korea, Russia and Japan, focusing on technologies including detection system, mining system and transportation system. In recent years, Chinese patent applicants have gradually predominated in the related patent application worldwide, reflecting China's great potential in R & D and market expansion of deep-sea mineral resources development technologies.

In order to improve the strength-ductility balance of medium manganese steel for automobiles, cold-rolled medium manganese steel was treated by annealing at different temperatures (650-680 ℃) and for different time (10-50 min) for austenitic reverse transformation. Then, effects of annealing temperature and holding time on the microstructure and mechanical properties of medium manganese steel were explored. It is found that the microstructure of the original cold-rolled medium manganese steel plate is composed of ferrite (F) and martensite (M), and the dispersed carbides with sizes ranging from 20 nm to 45 nm can be observed in the microstructure. As the annealing temperature rises from 650 ℃ to 680 ℃, the yield strength, elongation, strength-ductility balance, and residual austenite volume fraction of medium manganese steel increase followed by a decrease, but tensile strength increases all the time. As the annealing time is prolonged from 10 min to 50 min, the yield strength, tensile strength, elongation, strength-ductility balance and residual austenite volume fraction of medium manganese steel decrease after an initial increase. It is found that after annealing treatment at 660 ℃ for 30 min, the cold-rolled medium manganese steel has a structure composed of F + M + austenite (γ), with austenite at a volume fraction of 24.12%, ultrafine grained ferrite with an average grain size of 0.29 μm, lath martensite with an average wideness of 0.27 μm, and strength-ductility balance of 23.33 GPa·%.

The expanded graphite (EG) derived from the graphite anodes of spent lithium-ion batteries was taken as conductive substrate, and then Sn/Co-based bimetallic sulfide was loaded by using a hydrothermal method to synthesize SnCoS₄@EG nanocomposite. And such EG presents a cross-linked porous three-dimensional lattice, and the SnCoS₄ nanocrystals in the synthesized composite are uniformly dispersed in the EG, which enhances electrical conductivity of electrode material and stability of metallic sulfide, but also increases the contact area between active sites and electrolyte, leading to a higher exchange rate of Li⁺ ions at electrode/electrolyte interface. It is shown that SnCoS₄@EG electrode can exhibit a reversible specific capacity of 1 195.90 mAh/g at 1.0 A/g after 500 cycles, presenting excellent durability over a large number of cycles.

An iron concentrate obtained from magnetic separation of red mud from Shandong was used in an experimental study on the effect of titanium removal by reverse flotation. In the experiment, with sodium oleate as collector, corn starch as hematite depressant, sulfuric acid as pH regulator, pulp pH of 9, and the addition of corn starch and sodium oleate at an amount of 500 g/t and 1 500 g/t, respectively, the iron concentrate was produced, with the TiO₂ grade fell down from 6.90% to 2.73%, and the TFe recovery reaching 41.80%. The results of collector adsorption and IR analysis show that sodium oleate exhibits selective adsorption characteristics, which has further confirmed the feasibility of sodium oleate used in removing titanium by reverse flotation of iron concentrate obtained from magnetic separation of red mud.

An experiment was carried out with a pelletizing and magnetization roasting process for fine-grained specularite to investigate the pelletizing process, as well as the roasting performance and effect of pellets in the process of magnetization roasting. The results show that by adopting a process of fine grinding and pelletizing followed by magnetization roasting with an additionally prepared reducing agent, under the condition of roasting at 810 ℃ for 60 min, and addition of charcoal at an amount of 2.5%, a concentrate grading 49.04% Fe at 76.99% recovery can be obtained. In comparison, with a process of direct pelletizing followed by 60 min magnetization roasting at 650 ℃ with additionally prepared reducing agent and addition of semi-coke at an amount of 3.0%, the concentrate grading 52.95% Fe at 85.07% recovery can be obtained. It is found that the processing technique consisting of direct pelletizing and magnetization roasting is simpler and can bring better processing indicators. It can provide a reference for on-site processing of fine-grained specularite by adopting magnetizing roasting.

In order to utilize low-grade associated cassiterite resource from Huangshaping polymetallic ores, a new beneficiation process consisting of high-gradient magnetic separation (HGMS) for tailings discarding and tungsten-tin flotation for enhanced enrichment was developed based on the performed HGMS and flotation tests. After HGMS to pre-discard tailings, the loss rates of molybdenum, tungsten and fluorite were all less than 10%, while cassiterite was greatly enriched in the HGMS rough concentrates. Then, a flotation of reground HGMS rough concentrate was conducted by using Pb-BHA-SPA multiple ligand metal-based collector, producing a mixed tungsten-tin concentrate grading 0.627% WO₃ and 0.78% SnO₂, at corresponding recovery of 26.56% and 18.03%, respectively. This process provides a new idea and method for enhanced enrichment and effective utilization of low-grade associated cassiterite.

A heap leaching test was carried out for the low-grade copper-cobalt oxide ores from Congo (DRC), and effects of spray intensity, spray acidity and ore particle size on the leaching rates of copper and cobalt were investigated. The results show that both acidity and intensity of spray bring significant impact to the speed and cumulative rates of copper and cobalt leaching, while the ore particle size has little effect on leaching process. And finally, the optimal conditions for heap leaching of low-grade copper-cobalt ore were determined, including spray acidity at 20 g/L, spray intensity of 15 L/(m²·h), and ore particle size of less than 40 mm. It is shown that the cumulative leaching rates of copper and cobalt can reach 90.89% and 82.27%, respectively, after 100 days of heap leaching.

In order to balance productivity against safety in the mining of high-level stope with gently-dipping and extrathick orebody, an iron mine adopting sublevel open stoping with backfill was taken as an example to optimize the mining sequence. Firstly, pillars was determined to at a reasonable spacing from 14.2 m to 47.2 m based on the theory of bearing capacity of pillars. Secondly, according to stope structure parameters, the pillars were designed to be 15 m, 30 m and 45 m in thickness, respectively. An orebody model was also established with FLAC^3D and then was used to analyze the roof subsidence and pillar stability based on comparison of each mining scheme. Finally, a judgment matrix of mining sequence was constructed based on analytic hierarchy process and fuzzy comprehensive evaluation method, with both factors of safety and productivity taken into consideration in the numerical simulation. The comprehensive membership degrees of those three schemes were calculated to be 0.86, 0.79 and 0.80, respectively, and pillars in the best scheme were determined to be in the thickness of 15 m. The results of an industrial experiment have proven that this scheme can ensure stope with relative stability while achieving the maximum production capacity.