Use of combined solvent extraction-electrodeposition techniques to uranium and thorium isotopes analysis in industrial phosphoric acid, phosphate and phosphogypsum by alpha-particle spectrometry

Investigation of key factors in preparation of alpha sources by electrodeposition

The electrodeposition for alpha source preparation, using several electrolyte solution-cathode material combinations, is investigated and evaluated. The investigated factors focused on the electrodeposition time, the applied current, electrolyte volume and anode-cathode distances for the conventional electrodeposition cell (with no external stirring or cooling system). The conditions (temperature and the solution pH) during the electrodeposition process were also studied and discussed. The optimized parameters for each system are provided, and evaluated for the usage in determination of actinides (uranium, plutonium, americium and curium radioisotopes) in various samples.

Preparation of U(VI) and Th(IV) alpha-sources from sea and fresh water samples by combining coprecipitation, solvent extraction and electrodeposition procedures

A simple method combining coprecipitation, solvent extraction and electrodeposition for determining uranium and thorium in sea water and fresh water samples is developed. It offers a considerable saving in time, minimising chemical treatment and costs. The analytical procedure consists of enrichment of U and Th by coprecipitation with iron(III) hydroxides and subsequent extraction by diethylether solution and electrodeposition of each actinide in the extracting organic phase in which it was separated.

The dependence of the coprecipitation, the extraction-electrodeposition and the overall yields of the above mentioned elements is examined in relation to the initial aqueous solution acidity and various amounts of iron carrier. At an initial pH between 6 and 10, quantitative coprecipitation of U and Th requires use of an Fe(III) quantity which depends on the acidity of these solutions. This quantity varies, under explored conditions, between 10 and 110mg/L. At a starting pH of 11, this coprecipitation becomes almost independent of Fe(III) amounts.

The proposed procedure was used to analyse the content of U and Th isotopes in water samples. Recoveries of 60%-93% are obtained for uranium and 63%-86% for thorium. Good resolutions (37-56.5keV) are also achieved under optimum conditions. These resolutions allow to make accurate determination of U and Th isotopes in various water samples.