Recovery of industrial valuable metals from household battery waste

The modern community is dependent on electronic devices such as remote controls, alarm clocks, electric shavers, phones and computers, all of which are powered by household batteries. Alkaline, zinc–carbon (Zn-C), nickel metal hydride, lithium and lithium-ion batteries are the most common types of household energy storage technologies in the primary and secondary battery markets. Primary batteries, especially alkaline and Zn-C batteries, are the main constituents of the collected spent battery stream due to their short lifetimes. In this research, the recycling of main battery components, which are steel shells, zinc (Zn) and manganese oxides, was investigated. Household batteries were collected in Gothenburg, Sweden and mechanically pretreated by a company, Renova AB. The steel shells from spent batteries were industrially separated from the batteries themselves and the battery black mass obtained. A laboratory-scale pyrolysis method was applied to recover the Zn content via carbothermic reduction. First, the carbothermic reaction of the battery black mass was theoretically studied by HSC Chemistry 9.2 software. The effect of the amount of carbon on the Zn recovery was then examined by the designed process at 950°C. The recovery efficiency of Zn from battery black mass was over 99%, and the metal was collected as metallic Zn particles in a submicron particle size range. The pyrolysis residue was composed of mainly MnO2with some minor impurities such as iron and potassium. The suggested recycling process is a promising route not only for the effective extraction of secondary resources, but also for the utilization of recovered products in advanced technology applications.