Of the various dissolved species contained in the effluents from the mining and milling of uranium ores,
the one which is of particular concern for environmental protection is Radium-226. The literature shows
that, in recent years, considerable efforts have been made to develop treatment systems that can achieve
the stricter effluent discharge standards imposed by the regulatory bodies. There has also been a
concern to treat the already existent sludges from previous treatments. The main priority is to limit, as
much as possible, the arising of sludge from future treatment systems. The most common treatment
used is the addition of lime and limestone to raise the pH followed by barium chloride to form a very
finely divided Ba(Ra)S04 precipitate which is then settled in large ponds or basins. In spite of the high
decontamination factors obtained with this technique, these may not be satisfactory in terms of
environmental protection. In addition, the industry is increasingly aware of the economical benefits
resulting from treatment processes that allow water reuse to the process. [Continues.]
Summitted in partial fulfilment of the requirements
for the award of
Doctor of Philosophy of the Loughborough University of Technology.
European Commission. Directorate-General of Environment, Portugal.