Development of an organic acid–based hydrometallurgical route for the leaching and recovery of copper and cobalt from a copper–cobalt ore

Abstract

The use of inorganic reagents for metal extraction and recovery is often associated with significant drawbacks, including acid mine drainage, equipment corrosion, and the generation of toxic by-products. In this study, the feasibility of an integrated organic acid-based hydrometallurgical route for the leaching, separation, and recovery of copper and cobalt from a copper–cobalt oxide ore was investigated. The mineralogical and elemental compositions of the ore were characterised using X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS). Leaching of Cu and Co was carried out in a gluconic acid–H 2 O 2 medium. Under the optimum conditions of +75–106 μm particle size, 65 °C, 2.0 M gluconic acid concentration, 5.0 vol% 2.0 M H 2 O 2 , a solid-to-liquid ratio (S:L) of 1:20 (g/mL), 500 rpm and duration of 30 min, 94.8% Co and 92.7% Cu were leached. Kinetic analysis indicated that the dissolution of Cu as mixed control and Co as chemical controlled between 25 and 35 °C and mixed controlled between 35 and 65 °C. Cu was recovered from the leachate via a solvent extraction–stripping–electrowinning route, achieving 90.8% Cu extraction using oleic acid, 95.9% Cu stripping with sulfuric acid, and 99.9% Cu recovery through electrowinning. Co was recovered by precipitation using oxalic acid, resulting in 80.2% Co precipitation. These findings demonstrate that the employed organic acids are efficient for the extraction and recovery of Cu and Co from a copper–cobalt ore.