Extraction of Rare-Earth Elements from Silicate-Based Ore through Hydrometallurgical Route

Author(s)

Botelho Junior, Amilton Barbosa ; Romano Espinosa, Denise Crocce ; Vaughan, James ; Soares Tenorio, Jorge Alberto

• Document type: Journal article
• Source: METALS; v. 12, n. 7, p. 21-pg., 2022-07-01.

Abstract

The European Union and several countries/regions classified the rare-earth elements (REEs), such as lanthanum, cerium, neodymium, and scandium, as critical due to the risk of supply interruption. For this reason, the growing demand for REEs has resulted in forgotten reserves receiving economic interest. So, the search for new sources and the development of chemical process is important, such as silicate-based ore. Since there is almost no literature on the extraction of REEs from this source, a new approach was developed in the present study. Direct leaching and acid baking were studied using sulfuric acid. The effect of the acid concentration, temperature, solid-liquid ratio, oxidizing/reducing medium, and acid dosage were studied. Results showed that the extraction of REEs achieved up to 80% at 90 degrees C in oxidizing medium, and scandium and iron achieved 13.5% and 65.0%, respectively. For the acid baking experiments, the results were better than direct leaching for REEs at over 85%. The scandium leaching rate was lower than direct leaching. On the other hand, the extraction of iron was lower in acid baking than direct leaching. The iron and scandium extraction rates were higher in lower temperatures (<200 degrees C) and acid dosages, achieving 50% and 6.3%, respectively. Future studies should explore thermal treatment before acid leaching. (AU)

• FAPESP's process: 18/03483-6 - Kinect and thermodynamic studies for scandium recovery from Brazilian red mud using hydrometallurgical techniques
• Grantee: Amilton Barbosa Botelho Junior
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 19/11866-5 - Development of innovative processes for the recovery of critical metals
• Grantee: Denise Crocce Romano Espinosa
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/11417-3 - Obtaining Scandium from bauxite residue red mud by leaching process in acidic medium
• Grantee: Jorge Alberto Soares Tenório
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/51871-9 - Study Center for Technology in Waste Solid Treatment and Recycling - SCTWSTR
• Grantee: Jorge Alberto Soares Tenório
• Support Opportunities: Research Projects - Thematic Grants