The automated mineralogy: an important tool for geometallurgy studies of battery recycling

Since few years, a lot of companies and industries are developing battery recycling processes for the recovery of critical elements such as Li, Ni and Co. Before hydrometallurgical processing, mechanical and/or thermal treatment are applied in order to produce a black powder, also called blackmass. This high-value powder contains these above mentioned critical elements as well as graphite, rare earth metals and impurities such as solvents, plastics, aluminium and copper. The only data currently used to determine the quality of blackmass are chemical analyses of the major elements. However, micro-textures, liberation of elements and phases, as well as the amount of impurities in various phases are important parameters for the efficiency and performance of a hydrometallurgical process.

In order to evaluate the suitability for hydrometallurgical recycling process, it is essential to analyse the blackmass not only chemically but also with respect to size, shape and composition of particles. This presentation shows how these data can be acquired by using a refined QEMSCAN database. This database was created based on billions of point analyses on a total of some million particles. The results show that:

• Particles can be micro-texturally characterized and classified with respect to chemical element contents.
• Important textural and chemical particle variations exist in the blackmass of different origins showing different qualities.
• Elements deleterious to hydrometallurgical processing (i.g. Si, Mg, K, Ca, Fe, Al, Cu and others) can be present in specific and well liberated particles.
• Cathode active material compositions (different types of NMC as well as LCO, NCA, LFP, NiMH, etc) that are specific for each battery type can be distinguished.
• Digital simulation of additional physical mineral processing can optimize blackmass quality with respect to valuable elements.
• Special attention must be given to potential health risks during recycling and the processing of blackmass as elements like Cd and Co can be present in ultrafine particles.