Production of zinc and manganese oxide particles by pyrolysis of alkaline and Zn–C battery waste

Artikel i vetenskaplig tidskrift, 2016

Production of zinc and manganese oxide particles from alkaline and zinc–carbon battery black mass was studied by a pyrolysis process at 850–950 °C with various residence times under 1 L/min N2(g) flow rate conditions without using any additive. The particular and chemical properties of the battery waste were characterized to investigate the possible reactions and effects on the properties of the reaction products. The thermodynamics of the pyrolysis process were studied using the HSC Chemistry 5.11 software. The carbothermic reduction reaction of battery black mass takes place and makes it possible to produce fine zinc particles by a rapid condensation, after the evaporation of zinc from a pyrolysis batch. The amount of zinc that can be separated from the black mass is increased by both pyrolysis temperature and residence time. Zinc recovery of 97% was achieved at 950 °C and 1 h residence time using the proposed alkaline battery recycling process. The pyrolysis residue is mainly MnO powder with a low amount of zinc, iron and potassium impurities and has an average particle size of 2.9 μm. The obtained zinc particles have an average particle size of about 860 nm and consist of hexagonal crystals around 110 nm in size. The morphology of the zinc particles changes from a hexagonal shape to s spherical morphology by elevating the pyrolysis temperature.