Report for General Research September 18 to December 11, 1950 (Radium Volume)

The purpose of the research work reported in this volume is the development of a process for the separation and subsequent purification of radium from the K-65 (pitchblende) residue. Except for the accumulation of additional experimental data the process is essentially complete. After a preliminary extraction of about 85% of the lead and 40% of the silica with a 40% sodium hydroxide solution, the residue is treated with a solution containing both sodium hydroxide and sodium carbonate to obtain additional lead removal and partial conversion of the radium and barium sulfates to carbonates. After leaching out the soluble carbonates, the residue containing unconverted sulfates is treated with a sodium carbonate solution at 170{sup o} under pressure. A study of the amount and concentration of sodium carbonate required to obtain a satisfactory conversion of the sulfates has shown that the total sodium carbonate may be reduced by 40% and that smaller volumes of solution may be employed without serious decrease in the efficiency of the conversion. In order to make calculations on the number of steps and tank sizes for the radium-barium separation by fractional precipitation, equations have been developed to calculate this information from the theoretical separation factors determined experimentally. Three methods for carrying out the radium-barium separation by fractional precipitation of chromates have been studied and the separation factors determined. The methods differ in the reagent and temperature employed for the neutralization of the nitric acid solution of the chromates. The separation factor improves with decrease in temperature, and a marked improvement has been found by replacing urea which requires boiling temperatures for hydrolysis with potassium cyanate which hydrolyzes at much lower temperatures