5.1 Pyrometallurgy

In pyrometallurgy, full batteries or pre-processed materials such as shreds or black mass are subjected to temperatures exceeding 1000 °C in a furnace. This high-temperature treatment breaks down organic materials and separates metals based on their melting points and chemical reactivity. 

The process results in two primary material streams: 

• A metal alloy typically containing cobalt (Co), copper (Cu), nickel (Ni), and iron (Fe) 
• A slag that captures aluminum (Al), lithium (Li), manganese (Mn), and other less valuable or reactive elements 

In addition, the process generates dust or ash, which may contain residual metals, and off-gases that require treatment using filters, scrubbers, or regenerative thermal oxidizers (RTOs) to meet environmental regulations. 

Pyrometallurgy is highly effective for recovering nickel, cobalt, and copper, making it a popular route for mixed feedstock and contaminated materials. However, it requires significant energy input and generally results in lithium losses to the slag. 

To comply with EU or other regulatory recycling efficiency targets, some advanced pyrometallurgical flowsheets now include lithium recovery steps from slag and dust. Since the recovered metal alloy is not yet suitable for direct reuse in batteries, a follow-up hydrometallurgical refining step is typically required to produce battery-grade materials. 

While pyrometallurgy can accept a wide range of input materials—including battery packs, modules, cells, shreds, black mass, and manufacturing scrap—it is important to note that anode scrap is typically excluded. This is due to its high carbon content, which can interfere with the smelting process, affect furnace stability, and increase unwanted emissions during thermal treatment.