An investigation of radium extraction from uranium mill tailings

Uranium mill tailings contain small amounts of radionuclides that may result in low level radiation exposures to the population and environment over many years. The possibility of extracting a substantial portion of the most toxic radionuclide (226Ra) from sulfuric acid-leach process tailings from the Elliot Lake area was investigated by contacting with several leachants such as HNO3 and solutions of DTPA, EDTA and CaCl2.Data on the distribution of radium between the leachants and tailings were obtained for various contact times. Data on crosscurrent and countercurrent extraction were also obtained for the more promising extractants, and interpreted in terms of a pseudo-equilibrium model. Up to 85% of the radium could be removed by crosscurrent or countercurrent contacting with nitric acid or DTPA solutions.