Recoveries of Valuable Metals from Spent Nickel Metal Hydride Vehicle Batteries via Sulfation, Selective Roasting, and Water Leaching

Kivanc Korkmaz,Åke Rasmuson,Mahmood Alemrajabi,Kerstin Forsberg

doi:10.1007/s40831-018-0169-1

Kivanc Korkmaz, Åke Rasmuson + Show 2 more

Open Access

https://doi.org/10.1007/s40831-018-0169-1

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Abstract

The recoveries of rare earth elements (REEs), nickel, and cobalt from hybrid electric vehicle batteries by sulfation, selective roasting, and water leaching have been studied. The cathode and anode materials of a Panasonic Prismatic Module nickel metal hydride (NiMH) battery were used in the study. The optimal conditions for each step of the process were determined by performing lab-scale experiments. It was found that 8 mol/L of sulfuric acid was sufficient for the sulfation with a solid-to-liquid ratio of 1/5. The optimal roasting conditions was determined to be 850 °C for 2 h. Under optimal conditions, 96% of the REEs could be obtained in the aqueous phase with negligible contamination of Ni and Co. The Ni and Co remained in solid phase as oxides together with traces of aluminum, zinc, and iron oxides. This method provides a way for the separation of the REEs from nickel, cobalt, and other elements present in the NiMH battery, into a leachate suitable for further processing.

Highlights

Nickel metal hydride (NiMH) batteries are commonly used in many applications in our daily life
A nickel metal hydride (NiMH) battery is a source of rare earth elements (REEs) as well as of nickel and cobalt
Lanthanum oxysulfate was identified in the X-ray diffraction (XRD) pattern of the solid residues after water leaching in the roasting experiment R11, performed at 900 °C, Fig. 5b

Summary

Introduction

Nickel metal hydride (NiMH) batteries are commonly used in many applications in our daily life. They are available in many sizes and forms from AA batteries to all-electric plug in vehicles in hybrid electric vehicle (HEV) applications. The big companies in the automobile industry, such as Toyota, Honda, Ford, and Chevrolet have been using NiMH batteries in their HEVs since the early 1980s. Upon the end of the batteries life cycle, the need to recycle them has been gaining importance. A NiMH battery is a source of rare earth elements (REEs) as well as of nickel and cobalt. The European Commission has declared REEs as critical elements due to their supply risk where Asia is dominating the market [1].

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