Extraction of Radioruthenium by Nitrobenzene Solution of Polyvinyl Chloride

• Published in: RADIOISOTOPES Vol. 13; no. 6; pp. 450 - 454
• Main Authors: KODA, Yoshio, TANAKA, Motoharu, HUNG, Tsu-Chang
• Format: Journal Article
• Language: English; Japanese
• Published: Japan Radioisotope Association 1964
• ISSN: 0033-8303; 1884-4111
• DOI: 10.3769/radioisotopes.13.6_450

A rapid method of separation and determination of radio-ruthenium is proposed. The method is highly selective and allows the separation of radio-ruthenium from mixtures of fission products. When a large amount of sample water has to be treated as in the determination of radio-ruthenium in natural waters, ruthenium is preferably coprecipitated with hydrous ferric oxide prior to the final extraction step. The procedure is briefly given below: 5 mg of ferrous iron and 10 ml of 3 % hydrogen peroxide solution are added to every 1 liter of sample water, and pH of the solution is adjusted to about 6 using bromocresol purple as an indicator. The resulted hydrous ferric oxide is filtered through a glass filter. The precipitate is then dissolved in hot 1 N sulfuric acid. The solution is cooled and about 0.4 g of argentic oxide is added. After 10 minutes' standing at room temperature, the oxidation of ruthenium to the octavalent state is quantitative. Ruthenium tetroxide thus formed is then extracted with 0.1% nitrobenzene solution of polyvinyl chloride. Radionuclides such as 36Cl, 90Sr, 50Y, 99Tc and 74As are not extracted, distribution of these nuclides in favor of organic phase being very low. The over-all recovery of ruthenium of more than 98% is attainable. Ruthenium separated from mixtures of fission products shows a γ-ray spectrum identical to that of pure 106Ru-106Rh. Distribution ratio of ruthenium tetroxide between 1N sulfuric acid and the nitrobenzene solution of polyvinyl chloride is as high as 1, 000. Distribution ratios of ruthenium tetroxide between 1N sulfuric acid and some other organic solvents are also given.