JOM最新文献

This study uses sulfuric acid activation-water leaching method to decompose and leach iron from roasted cyanide tailings, thereby creating favorable conditions for the further leaching of gold from the tailings. The leachate obtained from the decomposition of iron is purified and then prepared into liquid polyferric sulfate. The gold in the leaching residue after iron decomposition is leached using cyanidation. The results show that at 100°C, by activating cyanide tailings with concentrated sulfuric acid for 1 h at a volume-to-mass ratio of 0.7:1, the leaching rate of iron can reach 82.64%. With 4000 g/ton of sodium cyanide used on the leached residue, the gold leaching rate can reach 83.4%. After reduction with iron powder, the strongly acidic, high-iron-content solution uses Na₂S as a precipitating agent to remove arsenic and zinc through a two-stage precipitation process. The arsenic content in the solution can be reduced from 253 mg/L to 5.01 mg/L, and the zinc content can be reduced from 207 mg/L to 65.8 mg/L. This study not only realizes the high-value utilization of waste but also reduces the accumulation of waste through the treatment of roasting cyanide tailings, which has a good application prospect.

301 stainless steel is austenitic stainless steel with excellent service characteristics. To fully reveal the influence of the spraying process on its surface characteristics, a 3D HVOF thermal spraying model was established in this study. The transient evolution for flame flow was simulated during the spraying WC-12Co powder on the surface of 301 stainless-steel substrate, and the particle distribution at different locations in the calculation domain was captured. The effects of substrate shape, spraying angle and spraying distance on the substrate temperature, strain rate and shear stress were analyzed. The results show that the temperature distribution affects the strain rate and shear stress on the substrate surface. The more uniform the temperature distribution, the lower the strain rate and shear stress. For the cylinder substrate, the strain rate and shear stress of 60° spraying angle are lower and concentrated on one side (upper part) of the substrate. The spraying direction should be selected from top to bottom, which can uniformly reduce the substrate surface stress and facilitate the high-quality coating formation.

New energy vehicles are gradually becoming widespread in China, and the quantity of installed and retired power LiFePO₄ batteries has increased. The traditional wet recovery process of LiFePO₄ cathode materials produces a lot of waste acid and waste alkali, which is inconsistent with the modern industrial concept of zero emissions and zero waste. This paper proposes a novel environmental protection process for direct remediation of spent LiFePO₄. Li₂CO₃ is the lithium source, and expired food-grade sucrose is used to reduce the spent LiFePO₄ cathode materials, which are then regenerated under the premise of achieving zero emissions and zero waste. When the addition of Li₂CO₃ is 4 wt% and the sucrose content is 15 wt%, the regenerated LiFePO₄/C material exhibits uniform particle size and favorable morphology. At 0.1 C, the initial discharge specific capacity is 156.15 mAh g^-1. At 5 C, its discharge performance is 106.01 mAh g^-1, and the electrochemical performance of the regenerated LiFePO₄/C material is similar to that of the commercial LiFePO₄. Moreover, the regulation mechanism of lithium replenishment repair in LiFePO₄ cathode materials is explored from the perspectives of material structure and physical phase composition.

The oxygen evolution reaction (OER) is known as a kinetics barrier in electrochemical water splitting. Developing stabilized non-precious metal-based catalysts is crucial for the wide application of electrolytic water splitting in oxygen production. Porous Co-based intermetallics function as promising non-noble metal catalysts for OER. Porous nanogrid-like Cu-doped Co-based materials (D-CAC) were prepared via the combination of rapid self-exothermic reactions and subsequent chemical dealloying. The Co-Al intermetallics possess high porosity and large specific surface area, which can promote mass transfer. On the other hand, proper metal doping is beneficial to adjust the absorption and desorption of oxygen-containing intermediate species. Accordingly, the D-CAC sample exhibited excellent OER activity with an overpotential of 370 mV@10 mA cm^-1 and a low Tafel slope of 52.7 mV dec^-1 in 1 M KOH. These findings offer a novel perspective on the efficient development of cobalt-based electrocatalysts for oxygen evolution.

The NASICON-type LATP (Li-Al-Ti-P-O) solid electrolytes possess good ion conductivity and high thermal stability, making them one of the most promising solid electrolytes for developing organic–inorganic composite solid electrolytes, especially the LATP@PEO (polyethylene oxide) composite solid electrolytes. At present, traditional coprecipitation methods are commonly used to prepare LATP. However, the LATP solid electrolytes prepared by this method possess low purity and crystallinity, multiple impurities, and difficulty in controlling grain size and morphology. These seriously restrict the improvement of ion conductivity of LATP@PEO composite solid electrolytes. Based on this, in this work, LATP was prepared by a continuous microfluidic coprecipitation method. Compared with the traditional coprecipitation method, the crystallinity of LATP obtained by the continuous microfluidic coprecipitation method was higher and the particle size dispersion was more uniform. Furthermore, it has been found that LATP@PEO composite solid electrolytes with high ionic conductivity (1.23 × 10^-5 S cm^-1) and low impedance (470 Ω) were obtained through a solution pouring method. The results show that the LATP obtained by continuous microfluidic coprecipitation is more conducive to improving the ionic conductivity and reducing the impedance of the LATP@PEO composite solid electrolytes than the LATP obtained by the traditional coprecipitation method. This finding suggests that the continuous microfluidic coprecipitation method would be the potential choice to prepare LATP solid electrolytes, and it possesses great prospects of industrial applications in the future.

With the introduction of low-carbon initiatives, China's metallurgical industry is undergoing a transition toward greener, low-carbon practices. Plasma technology, characterized by its high thermal performance, concentrated energy, significant chemical activity, rapid cooling rates, and controllable reaction atmospheres, has found extensive applications in this field. This paper reviews the advancements in plasma technology as applied to powder metallurgy, auxiliary combustion, and iron and steel production. In powder metallurgy, notable methods include discharge plasma sintering and plasma assisted combustion. In ironmaking, technologies such as plasma ironmaking and plasma direct reduction of iron oxide are employed. In steelmaking, plasma is utilized for melting, refining, and tundish heating processes. Currently, the application of plasma in sintering and auxiliary combustion remains limited, and there is a notable lack of in-depth research on direct reduced iron. Additionally, plasma metallurgy faces challenges, including short equipment lifespan, difficulties in controlling process parameters, and high costs. This paper proposes measures and methods to address these challenges, aiming to provide technical support for the large-scale application of plasma technology in metallurgy.

The effects of rolling temperature on the microstructure, mechanical anisotropy, and formability of 7B52 laminated aluminum alloy were studied using uniaxial tensile testing, Erichsen cupping test, scanning electron microscopy, and backscattered electron diffraction. The results indicate that 7B52 sheets are all well-bonded when rolled at 370°C, 420°C, and 470°C. The comprehensive mechanical properties of the sheet continuously improved as the rolling temperature decreased. When the rolling temperature decreased to 370°C, the as-quenched sample exhibited the lowest anisotropy and the optimum formability, with an in-plane anisotropy (IPA) value of 3.0 and an Erichsen index (IE) value of 6.9 mm. The excellent mechanical properties of the sheet are mainly due to the finer grains, lower grain aspect ratio, higher recrystallization volume fraction, and the balance of Goss and S texture components.