Characterizing Battery Recycling Residues with TESCAN TIMA

Why Black Mass Composition Matters for Efficient Recycling

Black mass is often treated as a black box — chemically rich, but structurally undefined. Yet the quality of any battery recycling stream depends on how well materials are sorted and separated. Without a detailed understanding of particle-level composition, valuable metals may be lost to waste, or incompatible chemistries may degrade recovery purity.

Conventional bulk techniques like XRF or ICP-MS can quantify elements, but not the phases from which they originate, or whether they are liberated or locked. A better approach is needed — one that sees each particle as a data point and provides a complete picture of composition, morphology, and association.

Automated Mineralogy Across Particle Size Fractions

Black mass material from Accurec Recycling GmbH was classified into four size fractions: <63 µm, 63–125 µm, 125–500 µm, and 500–1000 µm. Samples were embedded in iodine-doped epoxy to allow EDS-based quantification of carbon-containing phases.

Each fraction was analyzed using TESCAN TIMA, with categorization scripts distinguishing between key lithium-ion battery components: graphite, Al/Cu foils, lithium cobalt oxide (LCO), nickel manganese cobalt oxides (NMC), nickel cobalt aluminum oxide (NCA), lithium iron phosphate (LFP), and casing alloys. Phase identification was supported by EDS mapping and matched to chemical assay data from XRF for accuracy validation. Liberation and association metrics were calculated directly within the TIMA software.

Compositional Trends, Phase Associations, and Liberation Analysis

TIMA results showed a clear shift in material distribution across size fractions. Copper foils were most abundant in coarse particles, while graphite and oxidized aluminum foils occurred more frequently in the fine fractions. The analysis also confirmed a 2:1 weight ratio of LCO to NMC particles, with trace amounts of NCA and LFP. Crucially, liberation analysis showed that copper current collectors separate more efficiently from graphite than aluminum does from lithium metal oxides.

This behavior likely results from binder interactions, which cause oxide particles to remain attached to foils. TIMA also revealed the presence of alloy fragments and complex associations — including Cu entraining small Al or lithium metal oxide (LMO) particles — especially in the mid-size ranges. These findings provide direct evidence for refining mechanical treatment steps, optimizing sieving strategies, and adjusting chemical leaching stages based on actual particle behavior rather than assumptions.