Preparations for a Reduction and Liquid-Liquid Separation Experiment for Element 106, Seaborgium

Abstract

The purpose of this thesis was to check if it was possible to prepare a mechanical and chemical system that can reduce Seaborgium, element 106, and separate between the reduced and the oxidized state. To do this the liquid-liquid extraction system SISAK has been coupled to a flow electrolytic column, which is able to reduce single atoms. To overcome the high difference in flow rate between these two systems a membrane degasser has been utilized which managed to severely reduce the amount of fluid needed. Several extraction schemes have been tested. These had the goal that they should manage to strongly extract only one of the oxidation states. As a model for Sg experiments Mo and W have been used. During the work of this thesis it has been shown that it is possible to reduce and separate between two oxidation states of Mo. Furthermore, slight separation has been achieved for W in some systems. This have been done to model Sg in such a way that it is realistic to believe that Sg will behave in the same way. In addition a proof of concept has been achieved were the newly developed membrane degasser, the flow electrolytic column and the SISAK centrifuge have been coupled together. This managed to reduce enough Mo and separate between the reduced and oxidized Mo species at a flow rate of 0.2 mL/s and with the aquatic solution 0.1 M HCl + 0.9 M LiCl and an organic solution of 0.01 M hinokitiol in Toluene. Some kinetic studies have been performed at 0.2 mL/s flow rate with HDEHP as an extractant in toluene and an aquatic solution of 0.1 m H2SO4. Additionally retention on the carbon electrode is discussed. The work presented in this thesis have been performed as a part of a large collaboration between the nuclear chemistry group at the university of Oslo, Norway and between the superheavy element group in Tokai, Japan. An importan part of this work has therefore been to set up a working SISAK set-up in Tokai and a working flow electrolytic column in Oslo.