JOM最新文献

Spent Pd-Al₂O₃ catalyst was recovered by the metal smelting method. Cu and Fe were used as collector metals, and the capture process, smelting slag, and Pd-bearing alloy were comprehensively compared. The process condition results show that although the recovery rate of palladium of both capture processes is > 99%, the collection time using Fe smelting method is longer than that using Cu collection. The Si and P contents in Pd-bearing alloy under 1550°C obtained by Fe collection are obviously higher than those by Cu collection, which causes the difficulty in separation of Pd from impurities. The cost of Fe smelting process is much lower than that of Cu smelting process, while the metal Cu alloy can be further reused through subsequent electrolysis separation. Therefore, Cu collection is suggested to be a better collection metal due to the shorter smelting time, possible lower impurity content under higher temperature and more favorable subsequent treatment process.

The challenge of obtaining sufficient raw materials is a major concern when it comes to extracting lithium from spent lithium-ion batteries. One way to address this is through pyrometallurgical processing, which leaves undesirable elements such as lithium, aluminum and manganese in the slag. The engineered artificial minerals approach focuses on the effective recovery of critical elements. Different slag systems have been studied in the literature, and understanding the phase relationships in the (text {Li}_2{text {O}})-(text {SiO}_2)-CaO-(text {MnO}_x) system can lead to optimization of the recycling process. In this context, the stability of undesirable silicates can affect the maximum separation of Li from the slag. In order to contribute to the development of the Li recycling process, the stability of crystalline compounds was experimentally investigated in the present work for different slag compositions. The melted and solidified microstructures were characterized by SEM/EDX, EPMA, and XRD. Phase diagram data of binary and ternary systems were used to describe the solidification paths. As a result of solidification, crystals of (text {Li}_{2}text {SiO}_{3}) and (text {LiMnO}_2) were observed in a matrix consisting of (text {Ca}_{3}text {Si}_{2}hbox {O}_{7}) and (text {CaSiO}_{3}).

In order to further improve the density and properties of high-entropy boride ceramics, (Hf,Zr,W,Mo,Ti)B₂ high-entropy boride ceramics were prepared by boro/carbothermal reduction combined with SPS. The phase composition, microstructure, and mechanical properties of the ceramics were studied, and the results showed that (Hf,Zr,W,Mo,Ti)B₂ high-entropy boride powder contained a highentropy phase, an oxides impurities phase, a WB phase, and a HfB₂ phase at 1600 °C. After sintering at 2000 °C, there was no oxide impurity in the (Hf,Zr,W,Mo,Ti)B₂ high-entropy boride ceramics, which consisted of a high-entropy phase and a small amount of WB second phase. The hardness and fracture toughness were 29.9 ± 1.0 GPa and 3.36 ± 0.21 MPa·m^1/2, respectively. The hardness was higher than the high-entropy boride ceramics with the same components prepared by in situ reactive sintering and borothermal reduction. The mechanical properties of the high-entropy ceramics obtained by boro/carbothermal reduction was excellent. and were higher than those reported in the literature of the same component.

Spent automotive catalysts (SACs) are the most important secondary resource for platinum group metals (PGMs). Due to the complex physicochemical properties and low concentration of SAC, it is very difficult to recover Pt, Pd, and Rh. The technology of using smelting iron to recover PGMs has the advantages of a simple process and large-scale production. The rheological behavior of slag is an important influencing factor in the recycling process. In this paper, the principle of slag design is proposed, and CaO/SiO₂ mass ratio and B₂O₃ content are used as parameters to adjust the composition of the slag. The viscosity of slag was measured by the rotation axis method, and the structure of the slag was characterized by FTIR and Raman spectroscopy. The influence on the rheological properties and structure of slag was studied to optimize the smelting process. The optimized composition of the slag is 5.10 wt.%CaO-43.86 wt.%SiO₂-9.40 wt.%Al₂O₃-5.64 wt.%MgO-6.00 wt.%B₂O₃. In the reduction melting experiment, the recovery rate of PGMs reached 99.8%. This, furthermore, avoids the generation of ferrosilicon (FeSi), providing a reference for the effective recovery of PGMs.

Aluminum matrix composites hold promise for creating lightweight structural components with multifunctional properties. Nonetheless, achieving desired magnetic or electrical characteristics without compromising their fundamental mechanical properties presents a significant challenge. Here, we explore mechanical stir-based extrusion as a solid-state metalworking technique to develop fine-grained microstructures and highly refined metallic composites. Our study focuses on creating a SmCo₅-reinforced aluminum matrix composite using solid stir extrusion (SSE) and assessing its microstructure, mechanical, and magnetic properties through a comprehensive suite of characterization tools, including x-ray diffraction, electron microscopy, and magnetometry. Our findings reveal that incorporating a small amount (3.76 wt.%) of SmCo₅ phase in a non-heat-treatable, non-magnetic aluminum alloy via SSE yields a composite that exhibits good hard magnetic characteristics with a large coercivity (H_ci = 13.5 kOe) and improved mechanical properties. This study underscores non-equilibrium processing via solid-state high-speed stirring as a compelling method for crafting multifunctional materials with tailored mechanical and magnetic properties.

Optimally higher electrical conductivity and strength are most sought after but difficult to achieve in electrical grade Al alloys. In our study, we have investigated the improvement in both the properties of Al-Mg-Si alloy by introducing Al-8%B and Al-10%B master alloys to reduce the influence of impurity transition metals. Additionally, we conducted a comprehensive analysis to compare the performance of Al-8%B and Al-10%B master alloys, evaluating their respective abilities in boron treatment. Further, the focus was on the improvement of electrical conductivity and hardness of these alloys through heat treatment. We observed that the electrical conductivity and hardness consistently increased to a specific temperature threshold and then decreased. Finally, the study proposes a simple and easy to implement approach to optimize the electrical conductivity and hardness of Al-Mg-Si alloys by performing heat treatment with suitable parameters. This approach is less energy intensive, scalable, and involved with less time consumption in comparison to other practiced approaches.

Owing to its superior bulk mechanical properties, poly (ether ether ketone) (PEEK) has gained popularity over the past 15 years as a metal substitute in biomedical implants. Low surface energy is a fundamental issue with PEEK implants. This low surface energy caused by a moderately hydrophobic surface may be able to inhibit cellular adherence and result in the development of an inflammatory response, which may result in cell necrosis and apoptosis. In this work, plasma and ozone treatments have been utilized to surface activate PEEK and graft ionic bioactive polymer polyNaSS (poly (sodium styrene sulfonate)) successfully on the surface to promote cellular attachment and biomineralization. The main goal of our research has been to find a stable green process for surface modification of PEEK by plasma/ozone approaches to increase PolyNaSS grafting efficiency and biomineralization. To further the field of bioactive orthopedic and dental implant technology, this research attempts to address a significant constraint of PEEK implants while preserving their favorable mechanical properties.