METHOD OF EXTRACTING AMERICIUM Russian patent published in 2013 - IPC C22B60/02 C22B3/20 

FIELD: chemistry.

SUBSTANCE: invention relates to methods of extracting americium in form of americium dioxide from solutions. The invention can be used in the technology of extracting americium from production and radioactive wastes. The method involves concentrating nitric acid solution containing americium and impurities to americium content of not less than 100 mg/l by multi-step deposition of a precipitate containing americium, followed by dissolution thereof each time in a new portion of the starting solution. The precipitate containing americium is obtained from each portion of the solution by adding to 3.8-6.0 M nitric acid solution, which contains americium and impurities, ammonium hydroxide or an alkali metal hydroxide until achieving residual acidity of 0.1-0.2 M, oxalic acid to concentration of 10-50 g/l and adjusting acidity of the obtained reaction mixture to pH 0.6-2.3 if there are hydrolysable impurities in the starting solution and to pH 0.6-3.5 if not. The precipitate obtained by deposition from the americium-concentrated solution is then calcined and the calcined precipitate is then dissolved in nitric acid solution. Americium is then extracted from the obtained solution by a tributyl phosphate-based solid extractant, re-extracted, americium oxalate is deposited from the re-extract and then calcined to americium dioxide.

EFFECT: wider range of methods of extracting americium.

3 cl, 2 ex