Effect of different concentrations of sulfuric acid on leaching of radionuclide isotopes in sedimentary rock samples, Sinai, Egypt

This research focused on studying the effect of sulfuric acid concentrations on the leaching of different radionuclides (²³⁸U and ²³⁵U series) in two samples (high- and low-grade). The activity concentrations of radionuclides in the uranium series (²³⁸U and ²³⁵U) were measured by an HPGe detector. The leaching efficiency of ²³⁸U and ²³⁵U series was different in the samples and the leaching percent of ²³⁰Th was the highest in the samples, which may be due to the presence of the organic matter. There are radioactive disequilibria between ²³⁸U, ²³⁴U and ²³⁰Th in leachate and residual phase due to redistribution between acid-soluble and acid-resistant phases.