Lithium recovery from production waste by thermal pre-treatment

Abstract

Among the two types of lithium batteries, non-rechargeable primary-type batteries, and secondary-type rechargeable lithium-ion batteries (LIB), there have been efforts to recycle lithium only for LIB. Primary lithium batteries experience a vast market expansion with a present market volume of 2500–3200 t Li/a. Owed to a lack of apt technology, approx. 25% of this lithium is disposed of as lithium foil punching residues and is not recycled. The non-uniform lithium metal waste qualities, the high hazard potential when handling metallic lithium as well as the intake of impurities through the processing procedure are the main reasons why lithium from this source has not been recycled, yet.These problems have been solved through thermally converting lithium into Li2O and Li3N, followed by dissolution in water and precipitation with CO2, allowing for obtaining Li2CO3 already in battery-grade quality as a crude product (>99.5% purity) after precipitation. Accompanying iodine is recovered in analytical grade quality through sublimation. By means of design of experiments (DoE), a process has been developed and optimized that displays broad input material variability and consumes only water and CO2 as process chemicals. 83 ± 2.5% isolated yield of Li2CO3 was obtained by conducting the oxidation at 400 °C with 0.25 g residue of whatever origin for 2.5 h. As the products bg-Li2CO3, I2, and Fe2O3 are all marketable it is almost zero waste.