DETERMINATION OF RA-226 IN PHOSPHATE FERTILIZERS AND GYPSUM BY GAMMA-RAY SPECTROMETRY

The Ra-226 isotope was determined in 17%, 20% and 46% phosphate fertil izers and in gypsum. The fertilizer samples were dissolved in 10% nitr ic acid solution. The barium sulfate method was used for the precipita tion of Ra-226. An alkaline fusion method was used to separate the Ra- 226 from the gypsum. The Ra-226 concentrations present in these materi als were between 10(-4) and 10(-5) mu g g(-1). Neutron activation anal ysis was also used to verify the presence of uranium in the fertilizer s and gypsum; the uranium concentration in gypsum was 4.85 +/- 1.72 pp m.