Radium-226 Liberation from Uranium Ore Processing Mill Waste Solids and Uranium Rocks Into Surface Streams - I. The Effect of Different pH of Surface Waters

Intensive uranium ore mining and processing cause increasing contamination of surface waters with natural radioactivity not only of a pertinent residing region, but often of large areas. Most of the radioactive wastes penetrating into surface waters (mine waters, effluents from uranium ore processing mills, wash down from dumps and overburdens) contain radioactive isotopes bound before all to sedimenting matter. This paper presents the results of experimental studies of the dependence of radium release bound in radium ore and sediments on different concentrations of hydrogen ions in surface waters. Dried homogenized samples of uranium ore and sediments containing 226Ra to 14 pCi/g, 84 pCi/g and 540 pCi/g were shaken for 15, 30, 60, 180, 300 and 480 min with water of a pH modified in the range of 1–13. Radium was leached in 15–30 min of shaking in the maximum amount when pH was 1 (to 22%). With the increasing of pH the amount of released radium decreased to pH 9.