Dissolution and Characterization of Goldfieldite Ore from Wase (Nigeria) via Hydrometallurgical Leaching in Ammonia Solutions

Abstract

This study investigates the hydrometallurgical extraction of copper from a complex goldfieldite ore sourced from Wase, Plateau State, Nigeria. The raw ore was systematically characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS). Elemental analysis revealed an ore composition dominated by SiO₂ (57.89%), PbO (19.19%), CuO (8.91%), and Al₂O₃ (9.02%), with mineralogical phases identifying goldfieldite (Cu20.60Te5.20Sb1.71), cerussite, and quartz. Dissolution experiments were performed in an aqueous ammonium hydroxide (NH₄OH) medium to assess the impacts of lixiviant concentration (0.05–0.5 M), reaction temperature (25–75°C), and particle size (45–125 µm) as a function of time. The dissolution rate correlated positively with both increasing lixiviant concentration and temperature, while varying inversely with particle size. Under the operating conditions (0.5 M NH₃, 75°C, 45 µm particle size, and 120 min run time), maximum copper dissolution of 87.0%.was achieved. Mineralogical and morphological evaluations of the spent leached residue verified the systematic depletion of copper phases, leaving a residual matrix dominated by quartz and pyrrhotite (Fe36.00S40.00). These results underscore the viability of alkaline ammoniacal leaching for processing complex, low-grade copper-bearing telluride ores.