Rare earth elements are important resources for national development and industrial upgrading, and it is critical to establish an improved rare earth policy system. Based on the constructed analysis framework of rare earth policies, 48 rare earth policies issued from 1985 to 2022 in China were evaluated by using text data mining, social network and policy modeling consistency (PMC)-index model from three aspects, including the evolution process of rare earth policies, policy network and quantitative policy analysis. It is found that the evolution of China's rare earth policies can be divided into four stages, among which standardizing the exploitation procedure for rare earth resources and rectifying the order of rare earth market have always been the focus of China's rare earth policies. A policy network has been initially constructed, but there is poor correlation among policies and there are many isolated policies, which indicates that the correlation among policies needs to be strengthened. The overall design of the polices is reasonable, but there are some deficiencies in incentive measures and effectiveness. Finally, some suggestions are put forward to optimize and improve China's rare earth policies based on the features and shortcomings.

A side blowing furnace was adopted to treat the leaching residue of copper anode slime and recover valuable metals therein comprehensively. The effects of soda dosage, granular coal dosage, precipitation time and top flue gas temperature on the recovery rates of main metals Pb, Sb, Bi, Au and Ag were investigated. The results show that with soda at an amount of 2.5%, granular coal at an amount of 3%, the precipitation time of 1.5 h, and the top flue gas temperature of 750 ℃, the precious lead product is obtained after processing, grading 1 544 g/t Au (1.84 times enrichment), 10.37% Ag (1.4 times enrichment), 22.89% Pb (2.1 times enrichment), and 27.45% Bi (2.2 times enrichment).

In order to study the corrosion mechanism of welded material of Q370qENH weathering steel by submerged arc welding (SAW), experiments were conducted on immersion corrosion and electrochemical corrosion of Q370qENH substrate samples and weld seam samples after SAW process, and the morphology and composition of the surface rust formed after immersion corrosion were characterized. The results indicate that the corrosion resistance of the weld seam of Q370qENH by SAW process is lower than the substrate, and its electrochemical impedance is 38% of the substrate. The reason for the lower corrosion resistance of weld seam than the substrate and the formation mechanism of surface rust were all analyzed. The research results can provide scientific and theoretical basis for the safety assessment for the service of weathering steel in engineering projects of steel bridges for high-speed railway, as well as its following maintenance.

Fe₃O₄@SiO₂@IL was prepared by immobilizing imidazole based ionic liquids on the surface of magnetic nanoparticles with impregnation method, and was then used to remove Hg²⁺ in the water. The effects of pH value, adsorption time, and adsorbent dosage on the Hg²⁺ removal rate were investigated. The results show that Fe₃O₄@SiO₂@IL can have a wide application, and Hg²⁺ removal rate can exceed 99.1% with pH of 7.2-9.5. Fe₃O₄@SiO₂@IL presents a high rate of Hg²⁺ adsorption, and the adsorption can reach equilibrium within 90 minutes. For 25 mL Hg²⁺ solution with a concentration of 2 μg/mL, Hg²⁺ can be completely removed by adding 20 mg of adsorbent. The adsorption isotherms of Fe₃O₄@SiO₂@IL indicate that the saturated adsorption capacity of the adsorbent for Hg²⁺ is 548.37 mg/g.

The acid leaching solution of cathode materials from spent lithium iron phosphate batteries was taken as raw material, and iron, phosphorus and lithium elements therein were recovered by adopting an oxidation-precipitation process. The effects of factors, including endpoint pH value of reaction system, reaction temperature, concentration of sodium hydroxide, dripping rate of sodium hydroxide, and the volume ratio of hydrogen peroxide to acid leaching solution, on the precipitation rates of iron and phosphorus and the loss of lithium during the precipitation process were all investigated. Results show that with the endpoint pH value of 2.5, temperature of 75 ℃, sodium hydroxide with concentration of 1.5 mol/L, sodium hydroxide solution at a dripping rate of 7.7 mL/min, and hydrogen peroxide and acid leaching solution in a volume ratio of 1∶60, the average precipitation rates of iron and phosphorus are 99.86% and 98.23%, respectively, and the average loss of lithium is just 1.23%. Under the above-mentioned conditions, iron and phosphorus in the solution can be effectively removed and recycled in the form of iron phosphate, presenting a lower loss rate of lithium. After 5 h-heat treatment at 700 ℃, it is shown that the chemical composition of iron phosphate can meet the industrial standard.

The effects of aging treatment on the microstructure and properties of Al-Zn-Mg-Cu extruded bars were investigated. The results show that the alloys treated by two-stage aging and re-aging (TSR), retroregression and re-aging (RRA), and non-isothermal aging (NIA), compared to the treatment with T73, all present better intergranular corrosion (IGC) resistance, with the maximum corrosion depth down from 70 μm to 19, 48, and 30 μm, respectively. Compared to those treated by RRA and NIA, the TSR-treated alloy has the similar tensile strength and yield strength, but obviously superior IGC. After the treatment of T73, TSR, RRA, and NIA, the alloy has its grain boundary precipitates with average size of 27.7, 39.2, 31.6, and 25.5 nm, respectively, and matrix precipitates with average size of 8.1, 10.2, 10.9, and 11.0 nm, respectively.

The effect of strain rate on susceptibility of TB6 titanium alloy to adiabatic shear was investigated through dynamic loading of hat-shaped specimen of TB6 titanium alloy by using a split-Hopkinson compression bar at room temperature. The following results are obtained: all four groups of specimens exhibit obvious strain hardening effects at a strain rate of 1 950-2 510 s^-1; with the rising of adiabatic temperature, adiabatic shear bands (ASBs) form in all four groups of specimens due to thermoplastic instability; there is no obvious deformation gradient in the transition zone between the matrix and the adiabatic shear band due to the influence of impact load and material grain size; the equiaxed grains with size of 100 nm are formed in the hot shear band due to rotational dynamic recrystallization. By observing the metallographic structure, characterizing the adiabatic shear sensitivity, and calculating the expansion energy, it can be inferred that the susceptibility of TB6 titanium alloy to adiabatic shear increases with the increase of strain rate.

A new short-process preparation technique for battery-grade iron phosphate was explored with iron powder and phosphoric acid as main raw materials. The effects of iron powder dissolution mechanism, iron phosphate reaction conditions, and mother liquor recycle on product indicators were investigated. The results show that the dissolution rate of iron powder can reach 97.92% at a temperature of 70 ℃, with phosphoric acid at a concentration of 20%, iron and phosphorus at a ratio of 1/3, and iron powder at a size of 150 μm；after 1 h precipitation at 100 ℃, with an addition of hydrogen peroxide at 110% of the theoretical amount, an iron phosphate with D₅₀ of 2 μm was prepared with the precipitation rate of 98.86%. The obtained iron phosphate has stable crystal form with uniform crystal grains, and the contents of elemental impurities are significantly lower than the requirements specified in the HG/T 4701—2021 standard. The precipitated mother liquor in the process can be recycled, leading to actualization of low-carbon and green production.

An argyrodite-type sulfide solid electrolyte Li₆PS₅Cl (LPSC) was solid-phase synthesized by adopting high energy ball milling in combination with heat treatment. It is found that prolonging ball milling time is conducive to crushing, mixing, grain refinement and amorphization reaction process of raw material powder; increasing sintering temperature is beneficial to the formation of a single pure phase, but too high temperature for sintering can make electrolyte melted and decomposed, leading to destroyed crystal structure. It is found that after 10 hours of ball milling and 8 hours of sintering at 550 ℃, the synthesized sulfide solid electrolyte exhibits higher ionic conductivity, reaching 3.57×10^-3S/cm.

A statistical analysis was conducted for patents on acid-free descaling of strip steel in terms of the number of patents and main applicants, and those patents on typical acid-free descaling process for strip steel were specially discussed. Finally, the developing trend of acid-free descaling technology for strip steel in the future is presented, which can provide reference for R&D and application of acid-free descaling technology.