THE USE OF TRI-n-OCTYLPHOSPHINE OXIDE IN THE SOLVENT EXTRACTION OF THORIUM FROM ACIDIC SOLUTIONS

Thorium is readily extracted by a solution of tri-noctylphosphine oxide in cyclohexane from either acidic nitrate or chloride solutions. The maximum extraction coefficient in a nitrate medium is 380 as compared to 1300 for a chloride solution. In nitrate media the extraction coefficient is relativelv unaffected by changes in the anion concentration. In chloride media the coefficient varies directly with increasing chloride concentration, i.e., from about 0.4 in one molar chloride to the maximum in 7 to 10 molar. The acid concentration should be at least one molar. Thorium is not appreciably extracted from sulfate solutions. The extraction coefficient is of the order of 0.3. The addition of nitrate or chloride increases the coefficient sufficiently so that essentially 99% of the thorium can be extracted in a single equilibration. In perchlolate systems the extractlon is most efficient in one molar acid. The maximum (The above was unscabble material