CHEMICAL TECHNOLOGY DIVISION, CHEMICAL DEVELOPMENT SECTION C PROGRESS REPORT FOR AUGUST-SEPTEMBER 1960
A chemical flowsheet is proposed for recovery of strontium and rare earths from Purex wastes. The iron in the waste is first complexed with tartrate and the pH is adjusted with caustic. Strontium and rare earths are extracted by a solvent comprised of d1(2-ethylhexyl) phosphoric - sodium di(2- ethylhexyl) phosphate - tributyl phosphate-Amsco 125-82 and stripped with nitric acid. Processing the strip product through additional solvent extraction cycles yields isolated concentrated strontium and rare-earth fractions. In extraction of americium and rare earths from concentrated lithium chloride solution by tributyl phosphate (TBP) and by amines, aluminum chloride eliminated the need for added free acid. Hydrolytic precipitation was prevented by 1 to 2N AlCl/sub 3/ in lON total chloride, and the extractions were higher and more reproducible than from 10N LiCl-0.1N HCl. Neither aluminum chloride nor calcium chloride could be used to replace the 10N LiCl completely. Much higher separation factors were obtained for americium over europium (85) and cerium (>100) by extraction from 10N chloride solution with 0.5M trilaurylamine than with TBP. The americium extraction coefficient was low, 0.4, but sufficient for use in a separation process. Preliminary tests indicated higher extraction of curium. An activity with americium extraction coefficient was low, 0.4, but sufficient for use in a separation process. Preliminary tests indicated higher extraction of curium. An activity with a half life of about 175 days has been identified as isomeric with 6.7 days Lu/sup 177/. In completion of laboratory development of the process for recovery of technetium, neptunium. and uranium by tertiary amine extraction from uranium hexafluoride transfer cylinder wash solutions, re- extraction of technetium from the first-cycle product solution established a part of the extraction isotherm for further concentration and separation of technetium from nitrate in a second cycle. For control of the first-cycle nitrate separation step, a direct test with pH indicator solution successfully distinguished between <97, 97 to 99. and>99% hydrolysis of the amine nitrate. Estimates based on this close a control of hydrolysis, together with the separation factors found in the previously reported tests, indicate that a nitrate-removal section of perhaps oniy 12 ideal stages could be operated so as to produce an ammonium pertechnetate concentrate, essentially free from nitrate, as the single-cycle product. Nitrohydrocarbons, RNO/sub 2/, products of the reaction between hydrocarbon diluents and nitric acid, were previously identified as contributing to ineffective cleanup of TBP-Amsco 125-82 solutions. The testing has been extended to systems which have been exposed to gamma -ray irradiation. Again, degradation products of the diluent were more detrimental to solvent cleanup than those coming from TBP. Parallel testing of the di (sec- butyl) phenylphosphonate-Solvesso 100-nitric acid system showed similar cleanup behavior patterns, demonstrating that the formation of nitrohydrocarbons occurs in diluents of widely varying nature, e.g., primarily aliphatic vs. primarily aromatic. The vapor pressures of a series of water-saturated solutions of tri-n- octylamine in benzene indicate that this system obeys Raoult's law (i.e., is apparently ideal) up to about 0.2M. in confirmation of the hypothesis used previously in deriving equilibrium constants for the system TOA- C/sub 6/H/sub 6/ :H/sub 2/O-H/sub 2/SO/sub 4/. (auth)
- Research Organization:
- Oak Ridge National Lab., Tenn.
- NSA Number:
- NSA-15-005853
- OSTI ID:
- 4080393
- Report Number(s):
- CF-60-9-119
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMINES
AMMONIUM COMPOUNDS
BENZENE
CHEMICAL REACTIONS
CLEANING
DIAGRAMS
GENERAL AND MISCELLANEOUS
HALF-LIFE
HYDROLYSIS
IRON COMPLEXES
ISOMERS
LUTETIUM 177
NEPTUNIUM
NITRATES
ORGANIC ACIDS
PERTECHNETATES
PRESSURE
PUREX PROCESS
RAOULT LAW
RARE EARTHS
REPROCESSING
SEPARATION PROCESSES
SOLUTIONS
SOLVENT EXTRACTION
STRONTIUM
SULFURIC ACID
TARTARIC ACID
TECHNETIUM
TECHNETIUM COMPOUNDS
THERMODYNAMICS
TOA
URANIUM
URANIUM HEXAFLUORIDE
VAPORS
WASTE PROCESSING
WATER