Liquid wastes from mining and milling of uranium ores - a laboratory study of treatment methods

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Date
1976-10
Journal Title
Journal ISSN
Volume Title
Publisher
Australian Atomic Energy Commission
Abstract
Methods of reducing the concentration of contaminants in mine water and in the acidic raffinate from uranium milling operations have been studied. Lime, limestone, caustic soda and lime-soda ash mixtures were compared as reagents for neutralising raffinates and for removing amines and heavy metals including radium from solution. All methods of neutralisation reduced contaminant levels significantly. Two-stage neutralisation using limestone in the first stage to pH 4, followed by second stage lime treatment appears to be an economically attractive approach. This method usually gave the lowest residual radium concentration provided the solids from the first stage were not removed before adding lime. Radium can be further removed from neutralised raffinates or from mine water conditioned with sulphate by the addition of barium chloride to co-precipitate the sulphates of barium and radium. The concentration of radium was readily reduced to less than 3 pCi £-1 by adding 10 mg Ba £-1 raffinate. For mine waters conditioned to 0.01 M in sulphate, barium additions of 20 mg £-l were required to attain the same radium concentrations. Adsorption on barytes was also effective in removing radium from conditioned mine water and neutralised raffinates.
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Keywords
Amines, Coprecipitation, Liquid wastes, Uranium ores, Sodium hydroxides, Waste processing
Citation
Ryan, R., & Alfredson, P.(1976). Liquid wastes from mining and milling of uranium ores : a laboratory study of treatment methods (AAEC/E394). Lucas Heights, N.S.W.: Australian Atomic Energy Commission, Research Establishment.