Table I.
Determination of Fluoride in a Standardized Uranium Tetrafluoride Sample
Sample Taken, Gram 0.1930 0.2713 0.4189 0.2940 0,6999 0 5665 0,4053 0.459i
0.5331 0.5376 0 5666 0,4498 0 5785 0.4653 0.6218
(Calculated fluoride content 23.91%) Fluoride Found Gram c /O 7 23.78 0 0459 0 0645 23.77 23,99 0 1005 23 91 0 0703 23.77 0 1664 24.08 0 1364 23 88 0 0968 23 84 0 1096 23 7 i 0 1267 24 09 0 1295 0 1362 21.04 0 1065 23 68) 23 931 0 1383 0 1117 24 011 0 1479 23 i 9 J Mean 23.89 Std. dev. 10.13
ard de\-iation was 10.130 on a value of 23.9%, which was satisfactory for the purpose in hand. The mean value obtained from 15 experiments for the fluoride content of the sample was 23.89% against the theoretical value of 23.91%. This was calculated from the uranium tetrafluoride content (97.93%) and the uranyl fluoride content (1.69%) which n-ere determined in the S e w Brunsn-ick Laboratories of the U. S. Atomic Energy Commission. The results on the expcrimental materials were in agreement n ith the expected values. Operation of the columns was simple. The time required for elution of a sample was about 15 minutes and for regeneration about 10 minutes. The end point of the titration n-as also
Remarks Titration finished after removal of CO?
Titration carried out in presence of dissOl\TPd CO:
satisfactory, though not a5 sharp as when a strong mineral acid is titrated. Complete color change from pink (excess acid) to lemon-yellow was effected by adding about 0.5 nil. of 0 . 2 s sodium hydroxide. Although the change was gradual and went through the intermediate shades, the end point could be determined to within one drop of the standard solution. S o detectable losses of hydrofluoric acid resulting from interaction with the glass apparatus 11-ere observed. The use of plastic equipment. n-hich was not then obtainable, might lead to even better results. This analytical method is suitable for determining the total fluoride content in uranium tetrafluoride uranium hexa-
fluoride, and u r a n ~ - fluoride. l Uranium oxides and nietallic elements generally cause no interference but acids (except carbonic acid) must be absent. I n this respect, the method resembles that using pyrohydrolysis ( 1 ) . As all the uranium aiitl an!. other metal ions in the original sample \Till be removed from the column by hydrochloric acid, it should be possible to cletermine uranium in the same sanipk ns used for the fluoride determination. However, because of the ease with n-hich uranium fluoride can be dissolvetl and the uranium content can be determined rrhen the socliuin hydroxide-hydrogen peroxide reagent is used, this is usc,ful only when the sample is limited. ACKNOWLEDGMENT
The author n-ishes to thank Eltlorado Mining and Refining, Ltd., for permission to publish this paper. LITERATURE CITED
(1) Gillies, G . AI., Keen, 1.J., Lister, B. -%. J., Rees, D., "Determination by Pyohydrolysis of Uranium, Fluorine, and Oxide Impurity in Uranium Tetrafluoride," Brit. Atomic Energy Research Establishment C/M 225 (October 1954). (2) Rodden, J., "Ahalytical Cheniistry of the llanhattan Project," pp. 226-70, lIcGrav+Hill, S e n Tork, 1950. (3) Sporek, I
