(190d) Separation of Cerium From Leaching Solution of Monazite by Aeration Method

Rare earth elements are widely used in various fields due to their unique physical and chemical properties in accordance with the development of separation and purification techniques. Especially cerium is the most abundant in the series of rare earth elements, and the most widely used among rare earth elements. Cerium has chemically two stable valence states : Ce4+(ceric) and Ce3+(cerous). The ceric ion is a powerful oxidizing agent, and is completely stabilized when associated with the strongly coordinating ligand, oxygen. Ceric ion is precipitated as hydroxide compound at near pH 2.5 in acid media, but on the other hand the other rare earth elements are precipitated as hydroxide form between pH 6-7. Therefore acid-adjustment method of rare earth leached solution is widely used in the separation of cerium from the other elements. In order to separate cerium, cerous ion has to be oxidized to ceric ion preferentially. Aeration method was used to oxidize cerous hydroxide, and the effects of experimental variables such as aeration time, temperature solution on the oxidation of cerous were investigated and optimized aeration method in this study.