Selective roasting transformation to extract lithium from LiNi_0.815Co_0.15Al_0.035O₂ anode material of waste Tesla battery

To achieve the goals for "carbon peaking and carbon neutrality", the new energy industry has been strongly supported by national policies. With the rapid development of China's lithium new energy industry, the production and scrap volume of lithium-ion batteries, the core components of new energy vehicles, have been increasing. The comprehensive recycling of ternary lithium batteries, containing a large amount of valuable metals and hazardous wastes, are of both economic and environmental benefits. The traditional pyrometallurgy has the disadvantages of high energy consumption, high lithium loss rate and heavy pollution, and the routine hydrometallurgy also has the problems of long process, complex purification process, low comprehensive lithium recovery rate and a large amount of wastewater. At present, LiNi_0.5Co_0.2Mn_0.3O₂ (NCM) ternary anode materials are taken as the main research objects, while the recovery of new aluminum-containing Tesla battery materials is rarely reported. Therefore, with the typical Tesla ternary anode material LiNi_0.815Co_0.15Al_0.035O₂ (NCA) as raw material, carbon and hydrogen reducing agents, the lithium in waste lithium batteries was selectively extracted and recovered by reduction and roasting transformation—selective lithium extraction processes. Comparisons were conducted from the perspectives of reduction roasting and leaching methods, economic cost and environmental aspects. The results show that, by carbon reduction and roasting-selective lithium extraction process, the extraction rates of Li, Ni, Co and Al are 97.84%, 0.45%, 0.36% and 0.75%, respectively, at a carbon content of 15.0%, temperature of 700 ℃ and roasting time of 90 mins. The transition temperature is rather low when NCA materials are treated by hydrogen reduction roasting selective lithium extraction process. The extraction rate of Li is 95.97% and that of Al 8.65%, but the extraction rates of Ni and Co are both less than 0.5% at a roasting temperature of 500℃, hydrogen flow rate of 300 mL/min in the same roasting time. Meanwhile, no pollution gas such as CO and CO₂ is generated in the products. Therefore, hydrogen reduction roasting has a large potential for industrial applications.