PURPOSE: To simplify the separation of ruthenium by solving with nitric acid, the lead alloy obtained by adding bismuth and the like during the recovery in lead solving method, of noble metals contained in the non-soluble deposit produced in reprocessing factory for spent nuclear fuel.
CONSTITUTION: The components in non-soluble deposit of fission products to be recovered are mostly noble metals and form an alloy of hexagonal closest packing structure of five elements including moribdenum and technetium. When the fission products noble metals are recovered in lead solving method, bismuth or palladium is added, and then rhodium, for example, makes up metal compound with the added bismuth and the like and separates in lead. When nitric acid is added to this, the added elements solves in nitric acid and rhodium having formed metal compound becomes fine particles and is activated to solve in nitric acid. Since ruthenium does not form metal compound with the added bismuth, lead and the like, it remains as the deposit. The adding bismuth or palladium during the lead solving should be in the range between 5 to 10 times of weight ratio to rhodium.
MATSUI TSUNEO
NAKAHIRA HIROSHI
KITAGAWA MASATOSHI
OKADA HIROSHI
SUMITOMO METAL MINING CO