In order to recognize the dripping and the carburizing behaviors of the molten iron within the coke packed bed in the flash ironmaking process, a transient three-dimensional numerical model was developed. The volume of fluid (VOF) approach is used to describe the movement of the molten iron and the argon gas. The porous medium module is employed to define the momentum, heat, and mass transfer between the coke packed bed and the molten iron. Moreover, a factor is introduced to consider the influence of the ash film on the carburization process. A reasonable agreement between the experiment and simulation is obtained. The results indicate that the molten iron flows downward from the upper crucible to middle crucible. After entering the middle crucible, the molten iron spreads around within the coke packed bed and simultaneously moves downward. The carbon is, therefore, transferred from the coke to the molten iron. With the 47-mm-height coke packed bed, the carbon content in the molten iron after the carburization decreases from 3.19 to 1.97 pct, while the coke diameter ranges from 2 to 5 mm. With the 2-mm-diameter coke, the carbon content in the molten iron after the carburization increases from 2.84 to 4.81 pct, while the coke packed bed height increases from 37 to 97 mm.

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The tip-enhanced Raman spectroscopy (TERS) provides a non-destructive and label-free molecular detection approach with high sensitivity due to the hotspot excited at tip apex, which depends crucially on the tip parameters. Here, we employed an Au cladded atomic force microscopy probe to investigate enhancement effect of the Au claddings, both in theories and experiments. The simulation optimized a highest enhancement with Au cladding thickness of 50 nm under given experimental condition, being consistent with the experimental results. It provides a practical guide to optimize the probes to improve the TERS sensitivity and exert potentials in further TERS applications.@en

Electroslag remelting (ESR) technology has been innovatively employed to recycle the rejected electrolytic manganese metal (EMM) scrap. For a better understanding of the refining process, a transient three-dimensional comprehensive numerical model was developed based on computational fluid dynamics (CFD). With the assistance of the magnetic potential vector, the Maxwell's equations were solved for representing the electromagnetic fields. The movement of the manganese droplets was described by the volume of fluid (VOF) approach. A reasonable agreement between the simulations and experimental data is obtained. With the continuous melting of the EMM scrap, manganese droplets are formed at the inlet of the simulation domain and fall down and through to the slag phase afterwards. The highly conductive manganese droplet significantly changes the distribution of the current streamline and the Lorentz force around it. The droplet tends to rotate and move along the horizontal direction. With the current ranges from 5000 A to 8000 A, the volume-average Joule hating density and the time-average melt rate increase from 1.97×10 7 W/m 3 to 5.25×10 7 W/m 3 and from 0.029 kg/s to 0.073 kg/s, respectively. The average equivalent diameter of the manganese droplet increases from about 3.02 mm to 3.77 mm. The average residence time however first decreases from 5.12 s to 4.86 s and then rise to 5.24 s. The more vigorous molten slag would increases the motion path as well as the motion time of the droplet in the slag layer. @en

Copper and zinc were recovered from waste diamond cutters through leaching with an ammonia–ammonium sulfate system and air as an oxidant. The effects of experimental parameters on the leaching process were investigated, and the potential–pH (E–pH) diagrams of Cu–NH₃–SO₄ ²⁻–H₂O and Zn–NH₃–SO₄ ²⁻–H₂O at 25°C were drawn. Results showed that the optimal parameters for the leaching reaction are as follows: reaction temperature, 45°C; leaching duration, 3 h; liquid-to-solid ratio, 50:1 (mL/g); stirring speed, 200 r/min; ammonia concentration, 4.0 mol/L; ammonium sulfate concentration, 1.0 mol/L; and air flow rate, 0.2 L/min. The results of the kinetics study indicated that the leaching is controlled by the surface chemical reaction at temperatures below 35°C, and the leaching is controlled by diffusion through the product layer at temperatures above 35°C.

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