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

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 degrees C with an aqueous/organic (A/O) phase ratio = 1 v/v. The Co(11) 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 degrees 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. (C) 2012 Elsevier B.V. All rights reserved.