Experimental investigation of dust explosions with a focus on black mass in battery recycling

Abstract

The number of batteries in various applications at end-of-life and production waste from battery gigafactories increase significantly. At the same time, new EU regulations are introduced to promote battery recycling, which is a new and rapidly growing business. Large amounts of combustible dust are generated in battery recycling. Managing combustible dust hazards at the battery recycling plants is one of the key factors to minimize the incidents and down time and, therefore, to improve the work environment, and to increase the profitability of the business. Accordingly, the present work aims at exploring the risk of explosion of black mass dusts associated with battery recycling. Specifically, four black mass samples from different battery recycling plants are experimentally investigated. Microscope images, particle size distribution, water content and organic carbonates are analyzed. Dust explosion experiments are performed in a 20-L vessel. Parameters including dust concentration, ignition energy, ignition delay, dust injection pressure are varied. Results show that a 10 kJ ignition energy cannot generate high explosion overpressure, whereas an ignition energy of 20 kJ yields an explosion overpressure above 6 bar for black mass sample C at a concentration of 300 g/m³. The obtained experimental results are compared with published data on various explosion-related characteristics of other dusts relevant to battery recycling, in particular, aluminum and graphite dusts.