Separation of Cobalt, Nickel, and Copper from Synthetic Metallic Alloy by Selective Dissolution with Acid Solutions Containing Oxidizing Agent

ABSTRACT

The dissolution behavior of Co, Ni, and Cu and the metallic mixture in acid solutions like HCl, H₂SO₄, CH₃SO₃H, and CH₃COOH and their mixture with H₂O₂ was investigated. The effect of parameters such as acid and H₂O₂ concentration, pulp density, reaction temperature, and time on the dissolution of metals was studied. The CH₃SO₃H-H₂O₂ system showed highly selective leaching ability for Co over Ni and Cu from their metallic mixtures at low temperature. Under the optimum condition, Co can be selectively dissolved over Ni and Cu within 30 min at 20°C with 95.0% purity. Ni from the residues was selectively leached over Cu by either H₂SO₄ solution or the mixture of H₂SO₄ and H₂O₂ with above 99.9 and 95.6% purity in either method. A process has been proposed for the separation of the three metals by selective leaching from metallic alloys. This process shows some economic and environmental advantages such as significant decrease in the consumption of acids, reaction temperature, and time. Separation of metals by selective leaching resulted in solutions with high purity and obviation of the subsequent separation steps, which has a favorable effect on the process economics and environment. Thus, the process can be applied to the real operation.

KEYWORDS:

• Metallic alloys
• cobalt
• nickel
• copper
• dissolution
• separation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Technology Innovation Program (Development of Material Component Technology) (Project number: 2011183) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea).