Assessment of NORM in bauxite residue to facilitate valorization

Abstract

In the new Euratom Basic Safety Standard (BSS), materials with elevated concentrations of natural radionuclides can be considered as a potential source of radiological exposure. Such materials are often found in mining and metal extractive industries, where natural radionuclides are likely to end up and accumulate in the residue streams. Radiological assessment of the produced residues is a first and often sufficient step to demonstrate worker safety against radiological exposure. Bauxite Residue (BR) is an example of a material which has an elevated natural radionuclide concentration. BR used in this work is coming from Greece and was assessed to be below the BSS reference levels and therefore does not pose a significant risk of elevated radiological exposure. The processing of BR might result in further radionuclide accumulation in secondary residues, which also should be characterized to demonstrate the radiological safety of workers. In this work, the radiological properties of the residues produced after applying different extractive techniques for the recovery of iron, alumina and Rare Earth Elements (REE) were examined. All the analyzed samples were produced at the laboratory scale. The results suggest that for these residues, there is no significant radionuclide accumulation which would cause potentially elevated radiological exposure.