Radiological and chemical assessment of phosphate rocks in some countries

Abstract

In this study, the radiological, structural and chemical characterizations of Mardin-Mazi{dotless}da?i{dotless} phosphate rock, which is an important phosphate fertilizer source in Turkey were investigated and compared to those of several different phosphate rocks of Tunisia, Egypt, Morocco, Algeria and Syria using gamma spectrometry, X-ray diffraction (XRD) and X-ray fluorescence (XRF) measurement techniques. Elemental analysis results of phosphate samples showed that they were mainly composed of CaO, P2O5, SiO2, Al2O3, SO3 and Fe2O3. Elemental concentrations of U and Th were calculated using 226Ra and 232Th activity concentrations, respectively. As a result of XRD analysis, the main peaks of the samples were found to be Fluorapatite (Ca5(PO4)3F). The radioactivity concentration levels for 226Ra, 232Th and 40K in all phosphate samples ranged from 250 to 1029Bqkg-1 with a mean of 535Bqkg-1, from 5 to 50Bqkg-1 with a mean of 20Bqkg-1 and from 117 to 186Bqkg-1 with a mean of 148Bqkg-1, respectively. The computed values of annual effective doses ranged from 0.17 to 0.59mSv, with a mean value of 0.33mSv, which is lower than the recommended limit of 1mSvy-1 by the International Commission on Radiological Protection. © 2010 Elsevier B.V.