Lithium Recovery from NCM Lithium Ion Battery by Carbonation Roasting Followed by Water Leaching

Abstract

Lithium is a representative rare metal and ranks 32nd in abundance among elements in the earth’s crust. Lithium is used in a variety of applications, including the production of organolithium compounds, as an alloying addition to aluminum and magnesium, and as the anode in rechargeable lithium ion batteries especially for electronic devices and electric vehicles. Today, lithium is an indispensable metal in our daily lives. It is important to recycle lithium from used lithium-ion batteries to prepare for lithium shortages and protect lithium resources. The active cathode material of a lithium ion battery contains other valuable metals including Ni, Co, and Mn. In this study, the effect of carbonation temperature on Li recovery from NCM (LiNixCoyMnzO2) powder as Li2CO3 was investigated. First, a carbonation roasting was performed to convert the Li in the NCM powder into Li2CO3 at various temperature using a thermo-gravimetric analyzer. The roasted cinder leached into the water to dissolve the Li2CO3. The results showed that in Ar gas atmosphere the NCM phase was decomposed into Li2O and Li1-xM1+xO2 phases and the weight decreased by 4.7%, but in a CO2 atmosphere Li2CO3 was formed, resulting in a 12.1% increase in weight. In the isothermal experiment, the weight and carbon concentration of cinder increased with temperature, and the Li ratio in the NCM gradually decreased. The NCM powder was able to react with CO2 above 853 K, while some nickel, cobalt and manganese were regenerated into different Li1-xM1+xO2 crystalline phases. The maximum Li recovery rate of 76% wsa achieved for 2 h carbonation roasting at 1073 K followed by water leaching, filtering and an evaporative crystallization process.