Making waste profitable: Efficient recovery of metallic iron from jarosite residues

Abstract

To address the hazardous by-product of zinc smelting and resource utilization of jarosite residue, this study applies an electric field-assisted hot acid treatment to completely recycle Iron (Fe). This innovative approach aims to enhance the leaching efficiency of Fe from jarosite residue. The introduction of electric field changes the charge distribution on the surface of the particles to enhanced ions and electrons exchange and promotes the collision between particles to strengthen reaction kinetics. Based on the above, the leaching efficiency of Fe in jarosite under sulfuric acid attack is improved observably. The result shows that Fe leaching efficiency reaches 98.83%, which is increased by 28% under the optimal experimental conditions: current density of 30 mA/cm2, H2SO4 concentration of 1.5 mol/L, solid-liquid ratio of 70 g/L, temperature of 80 °C and time of 12 h. Leaching kinetics calculations shows that the apparent activation energy is 16.97 kJ/mol and leaching of jarosite residue is controlled by a mixture of chemical reaction and diffusion, temperature and concentration of leaching solution have influence on leaching. This work provides a feasible idea for the efficient leaching Fe from jarosite residue.