Leaching Kinetics of Crucial Metals from Bismutite Ore: Parameter Determination

Abstract

This study investigated the leaching kinetics of the crucial metals-aluminum (Al), iron (Fe), and zirconium (Zr) from bismutite ore using sulfuric acid (H₂SO₄) as the lixiviant. The influences of acid concentration (0.1–3 mol/L), leaching time (5–120 min), and temperature (28–80 °C) on metal extraction efficiency were systematically evaluated. The results demonstrated that increased acid concentrations and higher temperatures significantly enhanced metal recovery. The optimal leaching conditions were 2.5 mol/L H₂SO₄, a solid-to-liquid ratio of 100 g/L, and a temperature of 80 °C for 120 minutes, yielding leaching efficiencies of 99.82% for Al, 85.4% for Fe, and 99.2% for Zr. Kinetic modelling via the shrinking core model indicated that the process is chemically controlled, with activation energies of 31.06, 38.02, and 42.79 kJ/mol for Al, Fe, and Zr, respectively. The enriched leachate produced under these conditions is suitable for the subsequent selective recovery of target metals. This work supports sustainable metallurgical practices by promoting efficient, multi-element extraction from complex ores.