Processing of spent Ni-MH batteries for the recovery of cobalt, nickel and rare earth elements bearing materials by means of a chemical and electrochemical sequential process

Influence of Na+, K+, Mn2+, Fe2+and Zn2+ions on the electrodeposition of Ni-Co alloys: Implications for the recycling of Ni-MH batteries

“…The synthetic electrolytes were formulated in concordance with the composition of the solutions obtained by the processing of spent Ni-MH batteries [7]. In order to evaluate the influence of each ion independently, 6 solutions were prepared (Table 1).…”

“…New legislation changes issued in the Latin American countries have encouraged the application of valorisation strategies, not only to prevent environmental damage, but also to recover metal values from this kind of electronic wastes. A feasible solution for this local problem could be the adoption of small-scale hydrometallurgical facilities, in order to process these wastes without the need of exporting them to other countries, most of which are usually located in Europe and East Asia [7]. Nickel, cobalt and rare earths are strategic materials, which are worth to be recovered from depleted Ni-MH batteries; nevertheless, the hydrometallurgical recycling of Ni-MH batteries is a challenging issue, due to its internal chemical complexity [1][2][3][4][5][6][7][8].…”

“…Nickel, cobalt and rare earths are strategic materials, which are worth to be recovered from depleted Ni-MH batteries; nevertheless, the hydrometallurgical recycling of Ni-MH batteries is a challenging issue, due to its internal chemical complexity [1][2][3][4][5][6][7][8]. In a previous paper [7], a small-scale hydrometallurgical processing route was devised, comprising a chemical stage and an electrochemical stage. During the chemical stage, the active electrode materials of the Ni-MH batteries were leached using aqueous H 2 SO 4 .…”

“…A feasible solution for this local problem could be the adoption of small-scale hydrometallurgical facilities, in order to process these wastes without the need of exporting them to other countries, most of which are usually located in Europe and East Asia [7]. Nickel, cobalt and rare earths are strategic materials, which are worth to be recovered from depleted Ni-MH batteries; nevertheless, the hydrometallurgical recycling of Ni-MH batteries is a challenging issue, due to its internal chemical complexity [1][2][3][4][5][6][7][8]. In a previous paper [7], a small-scale hydrometallurgical processing route was devised, comprising a chemical stage and an electrochemical stage.…”

“…The obtained pregnant solution was then submitted to pH adjustment in a settling reactor, in which the rare earths were recovered as an insoluble complex sulphate. The remnant solution, containing nickel, cobalt and some other ions is then electrolyzed, in order to recover a Ni-Co alloy [7]. This latter stage is not yet well understood, because of the interaction of the several ions present in the solution.…”