REPORT FOR GENERAL RESEARCH FOR DECEMBER 11, 1950 TO APRIL 2, 1951. (Radium Volume)

The work presented in this volume concludes the research on methods for the recovery of purified radium from K-65 residues. The completion of a final report and an engineering study of the proposed process are underway. The preliminary treatment of the K-65 residues with 15% sodium hydroxide was checked and found to give 84% removal of lead and 40% removal of silica. The combined sodium hydroxide, sodium carbonate treatment for removing additional amounts of lead and achieving a preliminary conversion of the radium-barium silfates to carbonates has been studied at 170 deg C under pressure as well as at 100 deg C as previously used. A marked improvemont was found with the use of higher temperatures. Alternate methods were studied for removing the residual lead content in place of precipitation with hydrogen sulfide. Precipitation of insoluble hydroxides was found to remove about 90% of the lead present. The over-all recovery of radium in the residues treatment has been checked and found to be better than 98%. The work on the separation of radium from barium by fractional precipitation of the chromates has shown that in actual practices the results are in good agreement with the results calculated from the observed enrichment factors. The fractionation schemes have been worked out for the use of cyanide at 0 and 25 deg C and urea at 100 deg C. Additional measurements have been made on the solubility of barium chromate in nitric acid to determine the barium concentrations which can be handled in the fractional precipitation of the barium-radium chromates. The use of ion exchange for the separation of radium from barium appears to be most useful for the final purification of the radium. Additional experiments were directed toward increasing the amount of radium to the milligram level and toward determining, by extrapolation, the amount of barium in the radium fractions below the level which can be detected analytically. It has been found that the liquid wastes from the radium process can be effectively decontaminated by neutralization under the proper conditions. The decontamination obtained results largely from the precipitation of the lead sulfate which occurs when the solutions are neutralized. Additional experiments have shown femous suifide to be the most suitable precipitating agent found for a second decontamination step rather than the femous ferrocyanide previously suggested. Experiments have shown that the major pcntion of the nitric acid used for the conversion of the barium-radium chromates to nitrates can be recovered by distillation for reuse. (auth