A New Separation Process for Rare Earth Mixture with Low Yttrium Content

摘要

The low yttrium rare earth mixture was obtained from the extraction separation of ion-absorbed rare earth ore with high yttrium content (Y_2O_3 47% ～65% ) in Jiangxi by naphthenic acid-HCl system or other extractant. After the systematic studies on the flow-sheets of this mixture separation, and simultaneously according to the rare earth market, a new separation process for the low yttrium rare earth mixture was presented. The first step of the new process was the three-outlet process La-Gd / Tb Dy concentrate /Ho-Lu Y in HEH (EHP)-HCI system, Next, the heavy rare earth group (Ho-Lu Y) obtained from the first step was separated by Er Am process; the Tb Dy concentrate (Gd Tb Dy Ho Y) obtained from the first step was used as aqueous feed of Dy /Ho process, which extract (Ho YEr) was directly flowed into the extraction section of the Er /Tm process. In the new process, because the low yttrium mixture was divided into three groups at first, the content of rare earth element in respective groups were fast increased, such is more favourable to their separating further into individual rare earth product, producing more pure product easily, and increasing the yield of product of valuable element Tb. Dy. Er. etc. Separating high purity Tb and pure Dy product in the new process have the advantages of short flow path, high yield and low cost. The production control of the new process was relatively easy in comparison with previous process. The new process is especially suitable for some composition of the low yttrium mixture.