Optimization of mineral acids leaching process for the recovery of rare earth elements from Greek red mud

Rare earth elements (REEs) present a wide range of properties and applications in modern technology. Due to thorium co‐existence in their main ores, attention has been drown to exploitation of alternative resources such as apatite, bauxite, red mud, phosphates, mine tailings, etc. Red mud (RM), the byproduct of alumina’s production from bauxites by Bayer process, is a material produced in huge quantities up to 750.000 tons/year from Aluminum of Greece (AoG) with a content of ~1kg REEs/ton RM, including about 190 g scandium oxide/ton RM. A novel integrated procedure for the selective separation of REEs has been performed based on an over 20 years of experience 1, 2. In this study leaching experiments aiming to the selective recovery of REEs were conducted and co‐evaluated with previous research in order to optimize the process.