Numerical simulation of iron removal process characteristics and equipment optimisation in zinc hydrometallurgy

To address the challenges associated with the iron removal process in zinc hydrometallurgy, such as low reaction efficiency and excessive residue generation, this study employed numerical simulation to investigate the process characteristics within an industrial-scale iron removal reactor. The simulation revealed non-uniform transport characteristics, including relatively low gas holdup in the middle and upper regions and heterogeneous distributions of Fe2+ concentration and pH. These distributions indicate spatially non-uniform mass transfer within the reactor. Based on the simulation results, two equipment optimisation strategies were proposed and evaluated numerically. First, installing an additional impeller in the upper section increased gas holdup in the middle and upper regions and reduced the quasi-steady average Fe2+ concentration by 15.1%. Second, increasing the spacing between heating-coil turns reduced flow obstruction and improved mass-transfer conditions. This study provides a theoretical foundation and practical guidance for the structural optimisation and process intensification of industrial-scale iron removal reactors.