Waste reduction and high value utilization of jarosite-alunite residue (JAR) produced from the recovery of spent lithium-ion battery

The residue known as jarosite-alunite (JAR) is produced when the leach solution of spent lithium-ion battery is neutralized. This residue typically consists of Fe, Al, Na2SO4, Ni, Co, and Mn. It is classified as both a hazardous solid waste and a secondary resource. A unique hydrometallurgical technique was implemented to recover Na2SO4 and use Al extracted from JAR in high value applications. This extraction process involves phase transformation and NaOH leaching, with the pH adjusted in the range from 10.9 to 14. Initially, the JAR compound underwent dissociation to isolate SO42− as Na2SO4 by means of NaOH at a moderate pH, while the other metals were preserved as a hydroxide residue. Afterwards, aluminum in the hydroxide residue was selectively leached with NaOH leaving Ni, Co, and Mn in the remaining residue. The results indicated that over 93% of Na2SO4 and 86% of Al in JAR were effectively recovered as Na2SO4 and high value-added γ-AlOOH, respectively. Additionally, the enriched Ni, Co, and Mn in the alkaline leach residue were selectively recovered by H2SO4 leaching. The suggested procedure led to a significant decrease in waste by more than 67%, offering a fresh approach to effectively reduce waste and recover metals from JAR.