SEPARATING AND PURIFYING METHOD FOR FISSION PRODUCT NOBLE METAL

摘要

PURPOSE:To separate and purify a high purity palladium from a nitrate solution containing palladium and effectively recover the palladium by adding a boron hydride compound into a palladiumcontaining aqueous solution, reducing and precipitating palladium from the palladium-containing aqueous solution. CONSTITUTION:An extracting solvent containing dialkyl sulfide having an alkyl group having 4-10 carbon atoms as an extracting agent is brought into liquid- liquid contact with a palladium-contained nitrate solution which an provide a fission product noble metal contained in an insoluble residue generated in the retreatment process of spent nuclear fuel and in a high level radioactive waste by mixer-settler system to extract the palladium component in the solvent. The palladium extracting solvent is reversely extracted by a thio compound aqueous solution such as thiourea or ammonia aqueous solution, and a boron hydride compound is added to the palladium-contained aqueous solution to reduce and precipitate the palladium from the palladium-contained aqueous solution. The precipitate is solid-liquid separated by filtration, whereby metal palladium can be provided.