Physical separation, mechanical enrichment and recycling-oriented characterization of spent NiMH batteries
Journal article, 2018

Nickel–metal hydride (NiMH) batteries contain high amount of industrial metals, especially iron, nickel, cobalt and rare earth elements. Although the battery waste is a considerable secondary source for metal and chemical industries, a recycling process requires a suitable pretreatment method before proceeding with recovery step to reclaim all valuable elements. In this study, AA- and AAA-type spent NiMH batteries were ground and then sieved for size measurement and classification. Chemical composition of the ground battery black mass and sorted six different size fractions were determined by an analytical technique. Crystal structures of the samples were analyzed by X-ray diffraction. Results show that after mechanical treatment, almost 87 wt% of the spent NiMH batteries are suitable for further recycling steps. Size classification by sieving enriched the iron content of the samples in the coarse fraction which is bigger than 0.25 mm. On the other hand, the amounts of nickel and rare earth elements increased by decreasing sample size, and concentrated in the finer fractions. Anode and cathode active materials that are hydrogen storage alloy and nickel hydroxide were mainly collected in finer size fraction of the battery black mass.

Waste characterization

Spent batteries

Mechanical enrichment

NiMH battery

Physical separation


Burcak Ebin

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Martina Petranikova

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Christian Ekberg

Chalmers, Chemistry and Chemical Engineering, Energy and Material

Journal of Material Cycles and Waste Management

1438-4957 (ISSN) 1611-8227 (eISSN)

Vol. 20 4 2018-2027

Hydrochemical and pyrochemical recycling of metals from batteries

Swedish Energy Agency (P37714-1), 2013-12-01 -- 2015-12-31.

Areas of Advance




Materials Science

Subject Categories

Analytical Chemistry

Other Environmental Engineering

Environmental Management



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