Abstract
— This study investigates the leaching kinetics of chalcopyrite concentrate using three different lixiviants: sulfuric acid (H₂SO₄), ferrous sulfate (FeSO₄), and ferric sulfate (Fe₂(SO₄)₃) across a temperature range of 25°C to 65°C. Characterization of the chalcopyrite concentrate via X-ray fluorescence (XRF) revealed copper and iron as the dominant components at 32.88% and 27.82%, respectively, confirming economic viability for copper extraction. X-ray diffraction (XRD) analysis identified a complex mineralogical assemblage including chalcopyrite (CuFeS₂), bornite (Cu₅FeS₄), chalcocite (Cu₂S), covellite (CuS), and various gangue minerals. Scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) confirmed stoichiometric composition and revealed smooth, angular particle morphology with minimal surface oxidation. Kinetic modeling using the Shrinking Core Model (SCM) demonstrated temperature-dependent mechanistic transitions. For H₂SO₄ leaching, diffusion through the product layer dominated with correlation coefficients (R²) ranging from 0.90 to 0.99 and activation energies between 51.2 to 79.8 kJ/mol. FeSO₄ leaching exhibited chemical reaction control at elevated temperatures (55-65°C) with R² values reaching 0.98, while diffusion control prevailed at lower temperatures (25-45°C). Fe₂(SO₄)₃ leaching showed the most pronounced mechanistic shift, with diffusion control dominating below 45°C (R² up to 0.9959) and chemical reaction control above 55°C (R² = 0.9815). Copper recovery increased substantially with temperature across all lixiviants, ranging from 6-10% at 25-45°C to 15-22% at 55-65°C after eight hours. The formation of passivating elemental sulfur layers at lower temperatures and their breakdown at elevated temperatures explain the observed mechanistic transitions. These findings provide critical insights for optimizing industrial hydrometallurgical copper extraction processes from chalcopyrite concentrates. Keywords— Chalcopyrite, ferric sulfate, ferrous sulfate, sulfuric acid, leaching kinetic.