Sorption of Protactinium, Thorium, and Other Actinides from the LiF–NaF–KF Melt by Activated Carbon

Abstract

The sorption of uranium and thorium fluorides by activated carbon from the eutectic was studied. The sorption isotherms of both fluorides at a temperature of 650°C have a pronounced convex character and are described by the Langmuir equation. Experiments were carried out on the sorption of protactinium by activated carbon AG-3 at 650°С from a melt of alkali metal fluorides LiF–NaF–KF containing thorium and neodymium fluorides. It was found that with an increase in the concentrations of neodymium or thorium fluorides, the value of protactinium sorption diminishes, and in the case of thorium fluoride, the decrease occurs to a greater extent. When protactinium is sorbed by activated carbon with metallic sodium, the sorption enhances by a factor of 20 at the 30% sodium content in the carbon. The separation factors of protactinium from other actinides rise with increasing sodium content in the carbon.