Sorption of Subgroup IV, V and VI Elements on Ion Exchangers from HCl/HF Solutions. Model Experiments for Chemical Studies of the Elements 105 and 106 in Aqueous Solution

Abstract

The distribution coefficients of Zr, Hf, Nb, Ta, Mo, W, and Pa on cation and anion exchange resins from mixed HCl/HF solutions were determined in batch experiments by radiometric measurements. From solutions of 0.05 to 0.1 M HCl with 1.0 X10"' M HF a Separation of subgroup V and VI from subgroup IV Clements is possible on DOWEX 50X8. This system is proposed for the fast on-line Separation of the Clements 105 and 106. In column experiments with cation exchangers W can be separated from Mo. This opens the possibility to determine the chemical behaviour of element 106 in comparison to the lighter homologs. Differenccs in the Sorption behaviour of Ta, Nb and Pa on cation exchange resins from 0.1 M HCl/2.0 X10"" M HF Solution should allow a Statement as to which of these Clements, element 105 has the highest similarity.

Sorption Behaviour of Uranium on Cation and Anion Exchange Resins from HCl/HF-Containing Aqueous Solutions: Model Experiments for the Determination of Chemical Properties of Element 106 (Seaborgium)

“…Predictions of the sorption properties of elements in ultra trace amounts are difficult because the tracers may behave very different than macroscopic amounts under identical conditions. Speciation calculations using literature data for zirconium hydrolysis [11] and fluoride complexation [12] showed that ZrFl^ and ZrF^ are the main species in 0.05-0.1 M HCl/lO-'^-lO-^ M HF Solution [13], According to this speciation, the subgroup IV elements zirconium and hafnium should sorb on cation exchange resins, which we could recently confirm experimentally [1].…”

“…The suitable concentration interval of 0.05-0.1 M HCl/10-''-10'M HF for the Separation of subgroup VI from subgroup IV elements on cation exchange resins was developed using molybdenum and tungsten, zirconium and hafnium, respectively, as model elements [1]. Predictions of the sorption properties of elements in ultra trace amounts are difficult because the tracers may behave very different than macroscopic amounts under identical conditions.…”

“…The sorption of ^'^U on DOWEX 50X8 and DOWEX 1X8 is shown as a function of the HF concentration at constant HCl concentrations of 0.1 M. To compare this behaviour with that of tungsten and molybdenum, their sorption behaviour is also depicted in this figure. These sorption studies were carried out earlier under the same conditions as the uranium study; the details of sample preparation and Performance were given earlier [1]. Uranium is sorbed onto the cation exchanger over a wide ränge of HF concentrations.…”

“…DOWEX 50WX8 or AMINEX A6) from diluted HCl/HF-containing solutions are applicable for fast on-line experiments aiming to separate seaborgium. The suitable concentration interval for the Separation of the hexavalent Clements tungsten and molybdenum from zirconium, hafnium and lanthanides was found to be 0.05-0.1 M HCyi0"^-10^ M HF [1]. This chemical system was successfully applied in on-line experiments with short-hved tungsten, hafnium and lutetium isotopes [2].…”

“…The Sorption behaviour of carrier-free uranium from diluted HCl/HF or HNO3/HF solutions used in Üie experiments that were described above is yet unknown. To compare the chemical properties of seaborgium with those of uranium, we investigated the Sorption behaviour of ^'^U on cation and anion exchangers from HCITHF solutions under the conditions used in [1]. Our present experiments were carried out in "batch" modus where the experimental time is rather long in comparison to the reaction time.…”