Removal of ⁶⁰Co and ¹⁵²Eu in waste water from volume reduction treatment of activated concrete waste

When Co, Eu, etc elements, which are inherently present in the cement phase of concrete, are irradiated by neutron, ⁶⁰Co and ¹⁵²Eu are known to be generated, and are major nuclides in the irradiated concrete waste. It is known that the concrete usually consist of aggregate (gravel and sand) and cement and the radioactive nuclides exist in the cement phase. Accordingly, if the aggregate part is completely removed from the concrete, the volume of concrete waste to be disposed can be greatly reduced. The separation of cement and aggregate is known to be carried out by thermally-assisted mechanical way. The elements to be studied in this work were determined as major elements found in the solution prepared from actual dissolution of ordinary concrete including Co and Eu, as shown in Table 1. The radionuclides existing in the wastewater should be removed from the solution for the separated solution to be released to environment. The nuclides in the solution, of which concentrations are extremely low and lower than their solubilities, are known to be separated by coprecipitation using HFO (Hydrous Ferric Oxide) material and HAlO (Hydrous Aluminum Oxide). For that, it is necessary to understand exact hydro-chemical behavior of all the elements included in the wastewater. This work studied the thermodynamic behaviors of the major elements in the wastewater generated from the volume reduction process of concrete waste. The hydro-chemical behavior of all the majorelements of wastewater generated from concrete waste treatment were evaluated.