Life cycle assessment of enhanced materials recovery from LTO-rich anode waste recycling via froth flotation

Abstract

The introduction of alternative anode chemistries into the market, such as lithium titanium oxide (LTO), will likely generate challenges in lithium-ion battery (LIB) recycling processes. This study provides a life cycle impact assessment (LCA) for a hydrometallurgical battery recycling process enhanced with anode material separation via flotation. Life cycle inventory (LCI) was obtained through process simulation, assuming a feed of mixed battery materials including nickel manganese cobalt (NMC), LTO, and graphite. Two scenarios were modeled in which flotation separation was placed before the hydrometallurgical flowsheet (SC1) or, alternatively, placed to treat the leach residue (SC2). For SC1, the battery elements recovery rates were: 85 % Li, 92 % Co, 89 % Ni, 87 % Mn, 89 % Cu and 88 % Ti, whereas for SC2 they were 88 % Li, 94 % Co, 94 % Ni, 90 % Mn, 97 % Cu and 96 % Ti. The LCA results for the organics in solvent extraction (SX) were for SC1 energy resource fossil (ERf) 76 %, eutrophication freshwater (EThf) 71 % and global warming (GW) 69 %, while in SC2 were of 78 % and EThf and GW with 70 %. Acidification (AC) was not affected considerably by the routes, as normalized results showed a difference of < 5 %. Additionally, the simulation results showed that a longer flotation time in SC1 resulted in losses of lithium metal oxides (LMeOs) to the float stream. Nevertheless, although in SC2, EIs were higher compared to SC1, higher recovery yields with minimized waste generation could be demonstrated.