Schematic of the materials recovery process. Source: Michigan Technological UniversitySchematic of the materials recovery process. Source: Michigan Technological University

Chemical engineering students at Michigan Technological University look to the past to improve the future of lithium-ion battery recycling. They adapted tried and true technology used in the mining industry during the last century to selectively recover electrode materials from old batteries.

A froth flotation process similar to that used to separate metal from ore was tested with kerosene as the collector. The low-cost, low-energy scheme was demonstrated to recover graphite, cobalt, lithium and other critical materials. About 90 percent of anode materials and 10-13 percent of cathode materials were floated in froth layers. Standard gravity separation effectively separated copper from aluminum.

The froth flotation process using kerosene as the collector produced a tailing product having cathode materials of higher purity than those obtained without kerosene. For spent lithium-ion batteries, a low purity of cathode materials in tailings might be improved by fine grinding, which would expose freshly liberated hydrophobic surfaces and render more anode materials.

To contact the author of this article, email shimmelstein@globalspec.com