Hydrometallurgical route to recover nickel, cobalt and cadmium from spent Ni–Cd batteries

• Published in: Journal of power sources 2012-12, Vol.220, p.286-291
• Main Authors: Fernandes, Aline, Afonso, Julio Carlos, Bourdot Dutra, Achilles Junqueira
• Format: Article
• Language: English
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Metals recovery; Nickel precipitation; Ni–Cd batteries; Solvent extraction
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2012.08.011

In this work a hydrometallurgical route to recover nickel, cobalt and cadmium after leaching spent Ni–Cd batteries with hydrochloric acid was investigated. Co(II) and Cd(II) were both recovered by solvent extraction. Cd(II) was first extracted (99.7 wt.%) with pure tri-n-butylphosphate (TBP), in the original leachate acidity (5.1 mol L−1), in two stages at 25 °C with an aqueous/organic (A/O) phase ratio = 1 v/v. The Co(II) present in the raffinate (free acidity 4.1 mol L−1) was extracted with Alamine 336 or Alamine 304 (10 vol.% in kerosene) at 25 °C with an A/O ratio = 1 in two stages. 97.5 wt.% of Co(II) was extracted using Alamine 336 while only 90.4 wt.% was extracted in the case of Alamine 304. Ni(II) was isolated from the raffinate as oxalate after addition of ammonium oxalate at pH 2. ▸ Full metals separation in acidic medium. ▸ Cadmium and cobalt recovered by a sequential SX at high free acidity. ▸ Detailed study on cobalt extraction using tertiary amines in HCl medium. ▸ Nickel recovered as oxalate. ▸ Lower generation of final wastes.