Selective Precipitation of REE-Rich Aluminum Phosphate with Low Lithium Losses from Lithium Enriched Slag Leachate

• Published in: Materials Vol. 17; no. 20; p. 5113
• Main Authors: Marcinov, Vladimír, Oráč, Dušan, Klimko, Jakub, Takáčová, Zita, Pirošková, Jana, Jankovský, Ondřej
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 19.10.2024; MDPI
• Subjects: Aluminum; Aluminum phosphate; Ammonium hydroxide; Analytical chemistry; Batteries; Copper; Efficiency; Energy consumption; Leachates; Leaching; Lithium; Lithium-ion batteries; Phosphates; Raw materials; Room temperature; Scientific imaging; Slag; Sodium phosphate; lithium-ion batteries recycling; lithium-ion batteries; solution refining; aluminum precipitation; lithium recycling; solution purification; hydrometallurgy; aluminum phosphate; lithium slag
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17205113

Currently, recycling of spent lithium-ion batteries is carried out using mechanical, pyrometallurgical and hydrometallurgical methods and their combination. The aim of this article is to study a part of the pyro-hydrometallurgical processing of spent lithium-ion batteries which includes lithium slag hydrometallurgical treatment and refining of the obtained leachate. Leaching was realized via dry digestion, which is an effective method capable of transferring over 99% of the present metals, such as Li, Al, Co, Cu, and others, to the leachate. In this work, the influence of three types of precipitation agents (NaOH, NH4OH, Na3PO4) on the precipitation efficiency of Al and Li losses was investigated. It was found that the precipitation of aluminum with NaOH can result in the co-precipitation of lithium, causing total lithium losses up to 40%. As a suitable precipitating agent for complete Al removal from Li leachate with a minimal loss of lithium (less than 2%), crystalline Na3PO4 was determined under the following conditions: pH = 3, 400 rpm, 10 min, room temperature. Analysis confirmed that, in addition to aluminum, the precipitate also contains the REEs La (3.4%), Ce (2.5%), Y (1.3%), Nd (1%), and Pr (0.3%). The selective recovery of these elements will be the subject of further study.