Modelling the transport and fate of radionuclides in a sludge heap from the processing of phosphate ores

Abstract

The research project "Belgium NORM Site", coordinated by the Belgian Nuclear Research Centre (SCK*CEN), aims to prepare a study of the environmental impact generated by the sludge of calcium difluoride with radioactive elements, resulting from the phosphate industry. The phosphate rock, depending on its geological origin, may be enriched in natural radionuclides either from the uranium or thorium series (NORMs). Consequently, the processing of these types of ores generate by-products and residues also enriched in natural radionuclides (IAEA 2013). In this context, the physical, chemical and radiological characterization of soil samples and residues from the study site were performed. Also, natural leaching tests with different variants and determination of the coefficients of distribution among the main environmental compartments, were carried out. The results obtained will allow to develop mathematical models to describe the transport and transfer of the radionuclides (Dinis 2007), as well as other contaminants, and propose measures for the rehabilitation of the site.