Grain boundary diffusion technology has emerged as a pivotal approach to overcome bottlenecks of high cost and significant remanence loss in traditional single-alloy methods by precisely regulating the distribution of heavy rare earths (HREs), thereby markedly enhancing the coercivity of NdFeB magnets. This study proposed composite diffusion sources formed by blending Tb-Al-Cu HRE alloys with pure Nd powder at varying ratios, systematically investigating their diffusion modification effects on both HRE-free and HRE-containing substrates. Experimental results demonstrated that under optimal diffusion source ratios, the maximum coercivity enhancements for the two substrates reached 1.036 T and 0.959 T, respectively, with remanence attenuation controlled within 0.59 kGs and 0.43 kGs. When TbAlCu-to-pure-Nd ratio was 3∶2 (for HRE-free substrates) or 2∶3 (for HRE-containing substrates), the magnets exhibited optimal comprehensive performance, achieving 48UH and 45EH grade levels, respectively. Microstructural analysis revealed that HRE-free substrates developed increased grain boundary phases, refined grains, and core-shell structures after diffusion, while HRE-containing substrates showed a significant increase in non-magnetic grain boundary phases. By designing composite diffusion sources, this study achieved remarkable magnetic performance improvements with low HRE consumption, offering a novel strategy for the green preparation and resource-efficient utilization of high-performance NdFeB magnets.

Rare-earth permanent magnets (e.g., Sm-Co, Nd-Fe-B, Sm-Fe-N) are core components of high-performance magnetic materials, widely used in new energy, electronic information, and national defense. Compared with physical methods, chemical preparation techniques for rare-earth permanent magnets exhibit unique advantages such as atomic-level mixing, morphology controllability, and low-temperature synthesis, and are gradually becoming research hotspots. This review systematically summarized the research progress of chemical preparation technologies including the sol-gel method, hydrothermal method, co-precipitation method, thermal decomposition method, and emerging synthetic approaches. It analyzed the microstructure regulation mechanisms and magnetic performance optimization strategies, followed by discussion of current challenges and future development directions in this field.

With unique multi-principal element alloy system, medium and high entropy alloys exhibit a series of outstanding comprehensive properties: not only do they possess high strength and hardness, but they also have strong wear resistance and good chemical stability. In high-temperature environments, medium and high entropy alloys can still maintain stable structures and properties, and have excellent oxidation resistance. These properties make them widely used in aerospace, electronic processes, mechanical engineering and other fields. Due to the precise formula and uniform mixing of multiple elements involved in preparation of medium and high entropy alloys, there are extremely high requirements for purity of raw materials and accuracy of composition contents. At the same time, during the smelting process, in order to prevent problems such as composition segregation and non-uniform microstructure in medium and high entropy alloys, it is necessary to precisely control smelting parameters to ensure uniformity of the alloy composition and stability of the microstructure. This review sorted out a large number of domestic and international literatures. It summarized composition design of medium and high entropy alloys, and discussed preparation process of medium and high entropy alloy coatings and influence of process parameters on coating quality, providing references for innovation in material composition and structure of medium and high entroply alloy coatings.

Accurate determination of germanium (Ge) content in smelting dust is of great guiding significance for scientific recycling of smelting dust. Smelting dust contains a large amount of metastannic acid, which can encapsulate the sample, making it difficult to achieve complete decomposition using hydrochloric acid (HCl) and nitric acid (HNO₃). A variety of sample dissolution methods were investigated, and complete sample decomposition was achieved by using sodium peroxide (Na₂O₂)-hydrochloric acid-nitric acid for sample digestion. Meanwhile, the temperature was controlled to avoid the volatilization loss of germanium. The analytical line of Ge at 259.253 nm was selected, and contents of sample solution were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Overall, a method for determination of germanium in smelting dust was established. Under the optimized experimental conditions, mass concentration of germanium in the range of 0.50~15.00 µg/mL showed a good linear relationship with the emission intensity, with a linear correlation coefficient (r) of 0.99973, and a detection limit of 0.0013% (mass fraction). The matrix effect was investigated, and results showed that the coexisting elements in smelting dust had no significant influence on the determination of germanium. When the proposed method was applied to the determination of germanium in smelting dust samples, the relative standard deviation (RSD, n=11) ranged from 1.15% to 2.82%, and the recovery rate was in the range of 97.7% to 100.8%.

With the rapid advancement of electronic information technology and accelerated replacement of electronic products, the generation of waste electrical and electronic equipment (WEEE) has continued to increase, becoming a major environmental and resource challenge worldwide. Efficient copper recovery from waste printed circuit boards (WPCBs), a representative component of WEEE with high metal content, is particularly essential. This study focused on resource recovery of copper from WPCBs and systematically reviewed the main technological pathways currently applied, including physical-mechanical separation, thermal treatment, hydrometallurgical processing, and supercritical fluid extraction. Their performance was comparatively analyzed in terms of recovery efficiency, environmental impact, economic feasibility, and technical maturity. Results indicated that each technology exhibited distinct advantages in copper recovery, while several emerging technologies demonstrated strong potential to enhance recovery efficiency, reduce energy consumption, and mitigate secondary pollution. Based on these findings, the study proposed strategies to advance the high-value recycling of WPCBs, such as implementing multi-dimensional technology assessments, strengthening policy and financial support, establishing regional demonstration projects, developing localized green processes, and optimizing the recycling infrastructure. The novelty of this work lay in comparative analysis of multiple treatment technologies, comprehensive evaluation of their applicability to copper recovery, and formulation of systematic, context-specific countermeasures for China's WPCB recycling sector. These findings provided theoretical insights and technical guidance for promoting the sustainable and high-value utilization of WPCBs.

To address challenges of high fluoride concentration and strong corrosivity in waste acid from nonferrous metal smelting flue gas purification, which hinder the automation of treatment processes, a novel defluoridation reagent (JCFRR001) was developed. This study investigated the defluoridation performance of the proposed reagent. Results showed that the reagent exhibited good adaptability under fluctuating concentrations of sulfuric acid (5~55 g/L) and fluoride ions (F⁻, 5~25 g/L), achieving a consistent reduction of F⁻ to below 2.5 g/L in treated waste acid. Treatment of actual waste acid further demonstrated that, with initial F⁻ concentrations ranging from 5.6 to 18.4 g/L, the effluent F⁻ concentration decreased to 0.97~2.49 g/L after defluoridation. Resulting fluorite slag contained 77.47%~88.21% CaF₂ by mass, meeting the FF-75 grade requirements for fluorite concentrate (YB/T 5217—2019). Moreover, the study confirmed that the front-end defluoridation process had no significant impact on subsequent sulfide-based heavy metal removal process, thereby providing technical support for the automation of waste acid treatment systems.

Complex orebodies often exhibit intricate geometries, extensive branching and fault truncation, and the traditional practice of manually stitching wireframes one by one is inefficient and highly subjective. This paper proposed a refined and efficient modeling strategy tailored to complex orebody geometries. It formalized a signed distance field (SDF) definition and an efficient construction method based on contour lines, and implemented a hierarchical workflow—multi-wireframe automatic one-step modeling, local wireframe correction, and sporadic extrapolation modeling—that balanced automation with boundary fidelity. The method was validated on a structurally complex concession in the Democratic Republic of the Congo using the DIMINE platform. The overall modeling cycle was reduced from 230~440 h to 46~67 h. Over 170 mineralization models (≈1.91×10⁷ m³) and more than 180 orebody models (≈1.31×10⁷ m³) were successfully produced. Obtained models passed closure and topological validity checks with controllable errors. Results demonstrated that the proposed approach substantially improved automation for complex orebody modeling while retaining geometric accuracy at local mutation zones via secondary repairs, and thus offered a general technical path and implementation scheme for similar complex deposits.