Study of Uranium release from Uranium waste rock pile material: column experiments

Uranium release from the waste rock pile material was studied using modelled seepage water with various humic acid contents and flow-through velocities. The dynamic elution experiments using 233U-spiking, which were prepared on the basis of evaluated batch experiments, were preceded by equilibration of the rock material with solution in which the uranium total concentration was near to equilibrium determined in batch experiments. This type of experiments models real conditions in the waste rock pile for situations in which the release of uranium from the rock layer dominates. The observed influence of the presence humic acid on the release of uranium from the layer of rock pile material was variable and ambiguous, also due to the large retention of humic acid in the rock layer. (orig.)