Factors affecting the leaching of radium-226 from barium-radium sulphate sludges

CIM Bulletin, Vol. 82, No. 928, 1989

P.M. Huck, University of Alberta, and R. John, Environment Canada

The National Uranium Tailings Program was established in 1982 to develop, in part, a mathematical predictive model which would allow the assessment of the impact of uranium mill tailings on the environment and particularly on humans. To achieve this, various studies were undertaken to establish the role played by key constituents of the tailings. This paper summarizes the findings of a study carried out under that program, to examine the leachability of barium-radium sulphate sludges produced in the treatment of uranium mill tailings decants. The investigators performed detailed chemical analysis of the sludge, applied geochemical computer models to investigate sludge leaching behaviour, and conducted experiments to assess the impact of bacteria on leaching. The modelling showed that the redox state of the sludge-leachant system was the most important factor. Substantial bacterially-mediated dissolution of the sludge and release of radium was demonstrated experimentally under suitable reducing conditions.
Mots Clés: Mineral processing, Uranium tailings research, Environment, Barium-radium sulphate sludges, Leaching, National Uranium Tailings Program (NUTP), Radium-226