Selective leaching of a mixed nickel-cobalt hydroxide precipitate in sulphuric acid solution with potassium permanganate as oxidant

ABSTRACT

Selective leaching of a mixed nickel-cobalt hydroxide precipitate was investigated using potassium permanganate as oxidant in sulfuric acid solution. 94.9% Ni, 50% Co and 0.6% Mn were dissolved under the following conditions: sulfuric acid concentration of 0.75 M, potassium permanganate of 5 g/L, temperature of 30°C, leaching duration of 60 min, solid-to-liquid ratio of 1/10, and stirring speed of 400rpm. The pregnant leach solution was subjected to a solvent extraction process. 98% Co and 99% Mn were extracted at pH 4.84 with 30% (v/v) Cyanex 272, leaving essentially all nickel in the raffinate. Based on the experimental results, a flowsheet is proposed.

KEYWORDS:

• Selective leaching
• potassium permanganate
• mixed nickel-cobalt hydroxide precipitate
• solvent extraction
• nickel

Acknowledgements

This work was partially supported by The Scientific and Technological Research Council of Turkey (TUBITAK) (Project No: 216M405). Sait is also grateful to Meta Nickel for supplying the fresh MHP product. The authors thank the anonymous reviewers for improving the manuscript.

Additional information

Funding

This work was supported by The Scientific and Technological Research Council of Turkey (TUBITAK) [Project No: 216M405].