Roasting, Phase Transformation and Leaching of Valuable Metals in Spent Lithium-Ion Batteries

Leaching behavior of valuable metal elements in roasted spent Lithium-ion batteries was investigated. The pulp of LiCoO(2) or Co(3)O(4) mixed with concentrated sulfuric acid and one of sodium sulfate, potassium sulfate or ammonium sulfate was heated at a temperature range of 150 degrees C to 300 degrees C. The cobalt-containing transformation products of were then subject to dissolution in hot water. The dissolution rate of the products from LiCoO(2) was 56.4 similar to 100%, and 97.2 similar to 100% for the products form Co(3)O(4). The Na(2)Co(SO(4))(2)center dot 4H(2)O phases were detected in the transformation products with sodium sulfate, which were easily dissolved into hot water. Moreover, the mixture of roasted residue of spent lithium-ion batteries with concentrated sulfuric acid and sodium sulfate was heated at 300 degrees C. Li and Co in the mixture were leached out in hot water, the leaching rates of Cu and Al reached 84.7% and 93.6%, respectively. When roasting temperature is high than 300 degrees C, all these elements reach a high leaching rates, and Cu and Al can be leached out completely.