ملخص الدراسة:

The activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K in the kaolin and gibbsite samples collected from various localities of Sinai, Egypt have been measured using the γ-ray spectroscopy technique. For each sample, various characterizing quantities such as Ra_eq, H_ex, H_in, and Iγ values are calculated. All the values lie within the worldwide range. the dose rates of the most samples varies from 48.07 to 88.27 with average 46.21 which are agreement with the recommended limits (18-93 nGy h^-1) except two samples are high called T.3.2 in EL Tih I location (201.04 nGy h^-1 ) and M₆ in Mussaba Salama ( 98.33 nGy h^-1). The Chemical and mineralogy analysis show that the uranium concentration ranges from 2 to 18 PPm which are agreement with the recommended limits except M1 sample equals 44 PPm.and Fe₂O₃% ranges from 0.45 to 4.20 except one sample called T.3.2 equals 15.7% and AL₂O₃ ranges from 11.7 to 37.2 %. So it is desirable to used in industrial, where Kaolin and gibbsite is host several economic metal values. Which used in many important industries such as; paper industry, ceramics, refractory bricks, white cement, textiles, Rubber, medical industries, and special types of plastics.