LAUSR

Abstract Much attention has been paid to deal with cesium from the serious concern over the environmental threat as a well-known radionuclide. Radioactive cesium is usually precipitated and concentrated from aqueous waste before the final processing such as verification at high temperature for permanent storage underground somewhere. Few choices are available due to the high solubility of almost all the cesium compounds. A new idea is developed to use insoluble magnesium source to increase the efficiency of precipitating cesium as struvite (CsMgPO4.6H2O). Activated antigorite (Mg3Si2O5(OH)4) by ball-milling was used together with phosphoric acid to combine cesium chloride and form struvite at nearly stoichiometric ratio, even by simple agitation at room temperature. It is more interesting to notice that other alkali metals of potassium and sodium do not form stable struvite phase and remain in solution, giving a very high selectivity of cesium removal over potassium and sodium. This method may be applied both in cesium removal from the radioactively contaminated source and cesium concentration for metallurgical processing.