• Identified sequential intermediate products (green rust, feroxyhyte, weakly crystalline nanoparticles) during magnetite crystallization, revealing a dissolution-recrystallization transformation mechanism.
• Demonstrated that zinc binds strongly to green rust via adsorption and lattice substitution, explaining the difficulty in separating zinc from magnetite.
• First-time elucidation of zinc binding configurations with key intermediate products, providing mechanistic insights for optimizing iron and zinc separation.
• Offers a novel approach for iron removal and resource recycling in zinc hydrometallurgy, potentially reducing hazardous waste and environmental impact.