Recycling of nickel–metal hydride batteries. II: Electrochemical deposition of cobalt and nickel

Abstract

A combination of hydrometallurgical and electrochemical processes has been developed for the separation and recovery of nickel and cobalt from cylindrical nickel-metal hydride rechargeable batteries. Leaching tests revealed that a 4 mol dm −3 hydrochloric acid solution at 95• C was suitable to dissolve all metals from the battery after 3 h dissolution. The rare earths were separated from the leaching solution by solvent extraction with 25% bis(2-ethylhexyl)phosphoric acid (D2EHPA) in kerosene. The nickel and cobalt present in the aqueous phase were subjected to electrowinning. Galvanostatic tests on simulated aqueous solutions investigated the effect of current density, pH, and temperature with regard to current efficiency and deposit composition and morphology. The results indicated that achieving an Ni-Co composition with desirable properties was possible by varying the applied current density. Preferential cobalt deposition was observed at low current densities. Galvanostatic tests using solutions obtained from treatment of batteries revealed that the aqueous chloride phase, obtained from the extraction, was suitable for recovery of nickel and cobalt through simultaneous electrodeposition. Scanning electron micrography and X-ray diffraction analysis gave detailed information of the morphology and the crystallographic orientation of the obtained deposits.

AB5-alloy oxide/graphene composite anode with excellent cyclic stability for lithium ion batteries

“…Considerable effort has been devoted to recycling AB 5 -type alloys [8]. However, current approaches are based on the pyrometallurgical, chemical, and physical processes with high-temperature (above 1200°C), acids or bases, leading to the down-cycled metals or metal salts [9]. The most desirable recycling probably returns the recycled alloys to application for advanced batteries, whereas the reuse in lithium ion batteries is the most attractive.…”

Recycling of the rare earth oxides from spent rechargeable batteries using waste metallurgical slags

“…The rare earths are now considered as the most critical, with the highest supply risk raw materials 1 . Because there exist only few exploitable natural resources of rare earths in Europe, the EU will mainly have to rely on recycling of REEs from pre-consumer scrap and especially End-of-Life products, known as "urban mining".…”

Recovery of rare metal compounds from nickel–metal hydride battery waste and their application to CH4 dry reforming catalyst

“…The establishment of a method of recovering these elements from the waste in an environmentally thoughtful way is therefore desirable. The recovery of these elements from spent Ni-MH batteries has previously examined by extraction with organic solvent, magnetic separation and electrochemical deposition [1][2][3][4]. We are studying recovery process of rare metals from Ni-MH battery waste and spent Ni-MH batteries and utilization of recovered metals for environmental conservation.…”