Method for separating and purifying fission noble metals

• Main Authors: WADA; YUKIO, SHIMAUCHI; HISAAKI, NAKAHIRA; HIROSHI, SHIBAYAMA; HARUO, KIRISHIMA; KENJI
• Format: Patent
• Language: English
• Published: 02.04.1996
• Edition: 6
• Subjects: CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F; DECONTAMINATION ARRANGEMENTS THEREFOR; FERROUS OR NON-FERROUS ALLOYS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; INORGANIC CHEMISTRY; METALLURGY; NUCLEAR ENGINEERING; NUCLEAR PHYSICS; NUCLEAR REACTORS; PHYSICS; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULARRADIATION OR PARTICLE BOMBARDMENT; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PCT No. PCT/JP93/01332 Sec. 371 Date Sep. 19, 1994 Sec. 102(e) Date Sep. 19, 1994 PCT Filed Sep. 17, 1993.Fission noble metals contained in an insoluble residue and/or a high-level radioactive liquid waste generated in the step of reprocessing spent nuclear fuels are dissolved in nitric acid to prepare a palladium-containing nitric acid solution, which is then brought into liquid-liquid contact with an extracting solvent containing a dialkyl sulfide in which each alkyl group has 4 to 10 carbon atoms as an extractant to extract the palladium component into the extracting solvent. The palladium-containing extracting solvent is brought into liquid-liquid contact with an aqueous thio compound solution or aqueous ammonia solution to strip the palladium component into the aqueous solution. A borohydride compound in added to the palladium-containing aqueous solution to precipitate palladium from this solution by reduction, and metallic palladium is recovered by separating the precipitate from the aqueous solution.