In order to investigate the reaction behavior of associated thallium sulfide in zinc concentrate during fluidized roasting, thermodynamic calculation and verification experiments were conducted for the oxidation process of thallium sulfide. Firstly, the volatilization of thallium chloride, thallium oxide, metallic thallium and thallium sulfide were analyzed based on data retrieval and calculation, and the volatilization of those four matters was determined in the following descending order: Tl₂O>TlCl>Tl₂S>Tl. Then, the equilibrium analysis and the calculation of Gibbs free energy change of the Tl₂S-O₂ system were conducted. It is shown that Tl₂S volatilizes violently in an inert atmosphere as temperature rises, and decomposes into Tl and sulfur vapor after temperature is above 1 000 ℃. However, in an oxidizing atmosphere, Tl₂S begins to generate a large quantities of Tl₂SO₄ after the temperature reaches 100 ℃, and a few of Tl₂S begins to decompose into SO₂ and Tl₂O after temperature is above 1 000 ℃. No interaction occurs between Tl₂S and ZnO. In the practical roasting process, Tl₂S is completely converted into Tl₂SO₄ and remains stable in the calcine at the temperature above 800 ℃, which can be intensively removed in the subsequent open-circuit of leaching and purification process.

Based on the analysis of patent application trend, major applicants and technological development in recycling of spent lithium iron phosphate batteries by leaching process, a list of key patents of mainstream technologies is presented. The results show that the number of patent applications for recycling of spent lithium iron phosphate batteries by leaching process has been steadily increasing since 2015, and oxidative acid leaching is the mainstream technology at present, with other technologies keeping in pace. However, some outdated technologies are being phased out.

A thermodynamic analysis based on HSC Chemistry software reveals the phase evolution of main metals in the production of nickel matte by sulfidation smelting of copper-nickel electroplating sludge, and the optimal process conditions for obtaining medium-grade nickel matte by sulfidation smelting were also analyzed. Theoretical calculation shows that the electroplating sludge with grades of Cu and Ni at 3.0% and 3.5% respectively is smelted at a temperature of 1 300 ℃, with calcium sulfate as a sulfurizing reagent under a smelting atmosphere with in a volume ratio of 60%-75%, and the actual usage of sulfur 1.6-2.0 times the theoretical value. It is expected that medium-grade nickel matte with Fe content less than 20% can be obtained, and the contents of Cu and Ni in the slag with S ratio in the preferred range can be less than 0.20% and 0.43% respectively. It is shown that recovery rates of Cu and Ni exceed 95% and 90% respectively, and the fixation rate of Cr in the slag is over 99.9%. According to the statistical results of production samples, the distribution behavior of Cu, Ni and Cr is basically consistent with the thermodynamic analysis results. This proves that the established mathematical model has good reliability and is of certain guiding significance for production.

A low-grade manganese carbonate concentrate was processed by adopting direct sulfuric acid leaching. The effects of leaching parameters on the leaching rates of manganese, calcium and magnesium were investigated, and changes in phase composition and microstructure before and after leaching process were also discussed. The results show that under the optimized conditions, including acid and ore in a mass ratio of 0.6, liquid-solid ratio of 4∶1, leaching temperature of 60 ℃, and leaching time of 3 h, the leaching rates of manganese and magnesium reach 99.36% and 83.97% respectively, while calcium is hardly leached out and mainly left in the residue as calcium sulfate.

Multiferroic BiFeO₃ ceramics were synthesized by chemical co-precipitation. The effects of calcination temperature and time on crystal structure, morphology and grain size of products were investigated. Ions of Ba and Ti were doped to modify the properties of BiFeO₃ ceramics for improving ferroelectric and ferromagnetic properties. It is found that compared to the products before doping, the products with Ba doping at an amount of 30% in mass fraction can have the saturation magnetization enhanced from 4.69 emu/g to 4.93 emu/g; while the products with Ti doping at 10% in mass fraction can have the remnant magnetization enhanced from 0.047 emu/g to 0.164 emu/g. The co-doped ceramic samples combine the effects of A-site and B-site doping and exhibit enhanced multiferroic properties.

The thermal dissipation performance of a battery pack was optimized by thermal simulation, aiming to enhance safety and service life of batteries. A thermal simulation model of the battery pack was established with ANSYS software, and temperature distribution was analyzed for the battery discharged at 1C rate. It is found that the simulation results deviate from actual measurements by less than 0.5 ℃, confirming the high accuracy of the model. Two optimized thermal dissemination schemes were proposed, including I-shaped heatsink and thermally conductive adhesive filling. Study shows that both schemes can effectively improve the thermal dissipation performance, leading to the maximum temperature of cells reduced by 6.0 ℃ and 5.9 ℃, respectively. The scheme of I-shaped heatsink can not only reduce cell temperatures but also significantly reduce temperature differences, resulting in better thermal uniformity.

Bagasse was calcined under an inert atmosphere to produce biochar, which was then mixed with metakaolin and taken to prepare sugarcane bagasse biochar/geopolymer composite microspheres (BGM) by using sodium silicate as an activator. The microstructure of BGM was characterized by XRD, FTIR, BET and XPS, and its adsorption performance for crystal violet (CV) and methylene blue (MB) was also investigated. Results show that the introduction of biochar can enhance the adsorption capacity of metakaolin-based geopolymer microspheres. The adsorption processes of BGM for both dyes follow the pseudo-second order kinetic model. BGM-20 can have theoretically maximum adsorption capacities of 138.031 mg/g for CV and 79.128 mg/g for MB, which can be well-described by the Langmuir isotherm model. Dynamic adsorption experiments revealed that the time required for adsorption of CV and MB by BGM to reach exhaustion exceeded 8 500 min, indicating that BGM can be taken as a fixed-bed adsorption medium material for dye wastewater treatment.

The immersion end quenching method, combined with hardness testing, metallographic microscopy, scanning electron microscopy and transmission electron microscopy, was used to investigate the effect of quenching rate on the age hardening of 6061 aluminum alloy for building formwork. Results show that when the quenching rate decreases from 305 ℃/s to 26 ℃/s, the post-aging hardness of the alloy remains nearly unchanged. However, when the quenching rate drops below 26 ℃/s, the hardness decreases rapidly with further reduction in quenching rate. At quenching rates below 26 ℃/s, solute atoms precipitate from the supersaturated solid solution during cooling, forming β (Mg₂Si) phases without strengthening effect at grain boundaries, Al₁₃ (Fe, Cr)₃Si₂ dispersoids, and dislocations. This reduces the number of β″precipitates in the grains after aging, thereby lowering the alloy hardness. Lower quenching rates result in more β phases and lower post-aging hardness. It is concluded that the quenching rate shall exceed 26 ℃/s for attaining high hardness alloy.

In order to study the high-temperature and high-pressure sintering of binderless tungsten carbide (WC), X-ray diffraction, scanning electron microscopy, universal testing machine, and microhardness tester among others were adopted to characterize the phase composition, microstructure and mechanical properties of the WC samples. The results show that the relative density, hardness and fracture toughness of the samples increase as the sintering temperature rises. It is found that WC sample prepared by sintering at 1 500 ℃ can exhibit excellent comprehensive mechanical properties, with relative density of 99.5%, hardness of 2 885HV, and fracture toughness of 9.50 MPa·m^1/2.

Extreme high-speed laser cladding (EHLA) technology was used to prepare Al₂O₃-316L coatings on Ti6Al4V rods. The effects of scanning speed, powder feeding rate on single-track coating quality, and 316L powder content on multi-track coating quality and corrosion resistance were explored. Results show that with the following optimum process parameters, including scanning speed of 250 mm/s and powder feeding rate of 8 g/min, the coating can present superior quality with the 316L powder in a mass fraction of 20%. It is shown that all Al₂O₃-316L coatings exhibit superior corrosion resistance compared to the substrate. As 316L content increases, the corrosion resistance of coatings increases followed by decline. With 316L powder in a mass faction of 20%, the electrochemical impedance of the coating is 2.27 times that of the substrate.