Study on Roasting for Selective Lithium Leaching of Cathode Active Materials from Spent Lithium-Ion Batteries

Yeonjae Jung,Yonghwan Kim,Seongho Son,Bongyoung Yoo,Sungcheol Park

doi:10.3390/met11091336

Yeonjae Jung, Yonghwan Kim + Show 3 more

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https://doi.org/10.3390/met11091336

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Abstract

Recently, many studies have been conducted on the materialization of spent batteries. In conventional cases, lithium is recovered from an acidic solution through the leaching and separation of valuable metals; however, it is difficult to remove impurities because lithium is recovered in the last step. Cathode active materials of lithium-ion batteries comprise oxides with lithium, such as LiNixCoyMnzO2 and LiCoO2. Thus, lithium should be converted into a compound that can be leached in deionized water for selective lithium leaching. Recent studies on the leaching and recovery of Li2CO3 through a carbon reduction reaction show low economic efficiency, due to the solubility of Li2CO3 at room temperature being as low as 13 g/L. This paper proposes a method of roasting after nitric acid deposition for selective lithium leaching and recovery to LiNO3. Based on experiments involving the varying of the amount of nitric acid, roasting temperature, and solid–liquid ratio, optimal values were found to be dipping in 10 M HNO3 2 mL/g, roasting at 275 °C, and deionized water with a solid–liquid ratio of 10 mL/g, respectively. Over 80% Li leaching was possible under these conditions. IC analysis confirmed that the purity was 97% lithium nitrate.

Highlights

In recent years, the use of secondary batteries has increased rapidly owing to the increasing use of mobile devices and electric vehicles
There has been a significant increase in their usage in the case of electric vehicles, where large-capacity batteries are used, unlike those used in mobile devices
The organic matter in the black power led to a decrease in the lithium leaching rate

Summary

Introduction

The use of secondary batteries has increased rapidly owing to the increasing use of mobile devices and electric vehicles. There has been a significant increase in their usage in the case of electric vehicles, where large-capacity batteries are used, unlike those used in mobile devices. For electric vehicles and mobile devices, lithium-ion batteries (LIBs) with high energy density and low weight characteristics are commonly used [4,5]. It is difficult and costly to remove impurities using conventional processes, because Li recovery is conducted in the last step To overcome this problem, selective Li leaching has been actively studied [6–8], and involves leaching only Li after changing the phase of Li into a leachable phase by performing a carbon reduction reaction. A portion of Li in LiCoO2 in the active material reacts with carbon (C), thereby forming Li2CO3

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