Selective separation of radium and actinium from bulk thorium target material on strong acid cation exchange resin from sulfate media

Daniel R McAlister; E Philip Horwitz

doi:10.1016/j.apradiso.2018.06.008

Selective separation of radium and actinium from bulk thorium target material on strong acid cation exchange resin from sulfate media

Appl Radiat Isot. 2018 Oct:140:18-23. doi: 10.1016/j.apradiso.2018.06.008. Epub 2018 Jun 21.

Authors

Daniel R McAlister¹, E Philip Horwitz²

Affiliations

¹ PG Research Foundation, 1955 University Lane, Lisle, IL 60532, USA; Eichrom Technologies, LLC, 1955 University Lane, Lisle, IL 60532, USA. Electronic address: dmcalister@eichrom.com.
² PG Research Foundation, 1955 University Lane, Lisle, IL 60532, USA; Eichrom Technologies, LLC, 1955 University Lane, Lisle, IL 60532, USA.

PMID: 29936271
DOI: 10.1016/j.apradiso.2018.06.008

Abstract

This work presents a complete scheme for the selective separation of actinium and radium isotopes from bulk ²³²Th target material, in a process that may be applied in a separation scheme for the production of ²²⁵Ac by proton spallation on thorium. Thorium metal is dissolved in sulfuric acid with small amounts of HF. Actinium and radium are retained on cation exchange resin from the sulfate medium, while neutral and anionic thorium sulfate complexes are rejected. Following rinsing steps to remove residual thorium, actinium and radium are recovered from the cation exchange resin using 5 M HNO₃. Further separations of actinium via extraction chromatography with UTEVA and DGA resins yield actinium in >92% yield, while providing additional decontamination from thorium and other spallation byproducts. The radium fraction can be further processed following ingrowth of ²²⁵Ac from ²²⁵Ra to produce additional ²²⁵Ac free from any potential ²²⁷Ac impurity.

Keywords: (227)Ac; Actinium, (225)Ac; Extraction chromatography; Ion exchange; Nuclear medicine.