Solvent extraction-liquid scintillation method for assay of uranium and thorium in phosphate-containing material

Journal Article · Mon Jan 01 04:00:00 EST 1979 · Nucl. Technol.; (United States)

OSTI ID:6488067

Bouwer, E J ^[1]; McKlveen, J W; McDowell, W J

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1. Arizona State Univ., Tempe

A method utilizing solvent extraction coupled with liquid scintillation spectrometry has been developed for the assay of uranium and thorium in fertilizers and phosphate-containing minerals and chemicals. Trioctylphosphine oxide in toluene is used to extract uranium and thorium from a perchloric and nitric acid solution, with phosphate interference being suppressed by the addition of aluminum ion. The uranium and thorium are stripped from this solution, and uranium is separated from the thorium by selective reextraction of uranium into a scintillator with Adogen 364 (tertiary amine) sulfate. The thorium remaining in the aqueous is reextracted into another scintillator with (primary) 1-nonyldecylamine sulfate. Both nuclides are counted separately in a high-resolution liquid scintillation spectrometer. The sensitivity of the counting method is enhanced by the use of pulse-shape rejection of the beta--gamma background. Results indicate a detection threshold of 0.0038 pCi of uranium (1.1 part/10/sup 8/) with a 1000-min counting time. Reproducibility of +- 2.5% was found at the 50-ppM level. For thorium detection, thresholds are 4 part/10/sup 13/ for the same counting time with +- 3.0% average recovery of /sup 230/Th and 7 part/10/sup 8/ of /sup 232/Th.

• OSTI ID: 6488067
• Journal Information: Nucl. Technol.; (United States), Journal Name: Nucl. Technol.; (United States) Vol. 42:1; ISSN NUTYB
• Country of Publication: United States
• Language: English

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ACTINIDES
AROMATICS
CHEMICAL ANALYSIS
COUNTING TECHNIQUES
ELEMENTS
EXTRACTION
FERTILIZERS
HYDROCARBONS
LIQUID SCINTILLATION DETECTORS
MEASURING INSTRUMENTS
METALS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
RADIATION DETECTORS
SCINTILLATION COUNTERS
SCINTILLATION COUNTING
SEPARATION PROCESSES
SOLVENT EXTRACTION
THORIUM
TOLUENE
TOPO
URANIUM