Extraction of lanthanum and yttrium from red mud following elimination of ionic impurities

ABSTRACT

This study investigated the effect of atmospheric pressure agitation leaching method on lanthanum and yttrium extractions from red mud. In order to remove the undesired alkaline ions, the first stage leaching was carried out at pH 3, then, the leach cake was fed to the second stage leaching. At 40% solids ratio, 90.1% La and 91.6% Y extraction was achieved. It was determined that the leaching processes were controlled by a combination of chemical reaction and ash diffusion models. In terms of their dissolution behavior, a strong relationship between La and Y was found with a coefficient ratio of 0.95.

KEYWORDS:

• Red mud
• lanthanum
• yttrium
• multi-stage H₂SO₄ leaching
• kinetics