Numerical study on the gas-liquid interface in the hydrogen reduction of copper slag process.

• A validated numerical model explores interfacial dynamics during hydrogen reduction. • Periodic patterns in the gas–liquid interface, vorticity distribution asymmetry, and swirling patterns are revealed. • Mass transfer efficiency is higher in the bubble plume, influenced by gas flow in distinct regions. • The study provides insights for optimizing hydrogen reduction processes and enhancing mass transfer efficiency. Hydrogen reduction provides an environmentally friendly alternative to traditional smelting for copper slag. The study investigates the gas–liquid interface dynamics during the process. A numerical model based on Coupled Level Set-Volume of Fluid (CLSVOF) and Large Eddy Simulation (LES) methods has been developed and validated against experimental data. The model accurately depicts bubbling modes and interface characteristics in the reactor. Results indicate periodic self-similar patterns in interfacial area and gas volume signals. The vorticity distribution shows asymmetry and swirling patterns, with higher vorticity in the gas injection and upper liquid surface regions. The mass transfer efficiency is higher in the bubble plume region than in the upper surface. Increasing gas flow rates expands the gas–liquid interface areas but decreases mass transfer efficiency in the bubble plume while increasing it in the upper surface. These findings provide valuable insights into the efficiency of the hydrogen reduction of the copper slag process. [ABSTRACT FROM AUTHOR]