Low-acid leaching of lithium-ion battery active materials in Fe-catalyzed Cu-H2SO4 system

Antti Porvali,Sugam Shukla,Mari Lundström

doi:10.1016/j.hydromet.2020.105408

Antti Porvali, Sugam Shukla + Show 1 more

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https://doi.org/10.1016/j.hydromet.2020.105408

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Journal: Hydrometallurgy	Publication Date: Jun 23, 2020
Citations: 17	License type: cc-by

Affiliation: Aalto University

Abstract

Leaching of active cathode materials of Li-ion batteries (LIB) is a hotly contested topic. In the published literature, the best processes utilize concentrated acid (e.g. 2–3 M H2SO4) and elevated temperatures for waste LIB leaching, along with unstable reduction reagents such as H2O2. In this study, we demonstrate the dissolution of LiCoO2 (LCO) in a low-acid leaching system that utilizes typical battery elements which can be found in impure, recycled black masses; Fe2+ as a reducing agent towards LCO, and Cu as a reducing agent towards Fe3+. We show for the first time that the Cu-Fe2+-H2SO4 system can provide an excellent performance in dissolving LCO materials at low acid environment and near-room temperature (T = 30 °C), even to the point where the acidity of the solution decreases to pH = 1.89 while reaching Co extraction of 92%. To the best of our knowledge, such high leaching efficiency has not been previously reported under such mild conditions. Nowadays, recyclability of the process waters may also be important, and herein we highlighted the influence of Na2SO4 on leaching of LCO active materials as well in this system. Minimization of the lixiviant concentration and temperature is beneficial in allowing decrease in chemical and energy consumption. High pH operation also can support further downstream processing, helping to avoid the problem of sodium accumulation towards the end-stage where lithium is recovered.

Highlights

There is a strong on-going push towards electrification of society
We show for the first time that the Cu-Fe2+-H2SO4 system can provide an excellent performance in dissolving LCO materials at low acid environment and near-room temperature (T = 30 °C), even to the point where the acidity of the solution decreases to pH = 1.89 while reaching Co extraction of 92%
We have shown that low acid leaching under room temperature can provide a higher final yield with a sufficient kinetics compared to high acid leaching

Summary

Introduction

There is a strong on-going push towards electrification of society. Recently, Tesla produced their millionth electric vehicle (EV), with the other automotive makers are following in suit, and lithium-ion batteries (LIB) are playing a key-role in this revolution. The rapid adaptation of LIBs in EVs, stationary storage applications and vast array of consumer products, such as mobile phones, laptops and other electronics, have opened new opportunities to businesses This has given a new responsibility to hydrometallurgists: these batteries and their components need to be recycled, this most likely requires hydrometallurgical expertise at some part of the recycling process if the components are downcycled back to reagents (Fan et al, 2020; Harper et al, 2019). Present industrial activities are focused in particular on recycling of Co and Ni, found in lithium–cobalt oxide (LCO) and nickel–manganese–cobalt oxide (NMC) types of batteries (Chagnes and Swiatowska, 2015) These metals are the most valuable components in the batteries, whereas Li is often lost. In 2013, 32,000 t of LCO cathode materials had already been produced (Chagnes and Swiatowska, 2015)

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