Exploration for uranium in phosphorites. A new study on uranium in Israel phosphorites

Phosphorites are attractive as an additional source of uranium for many reasons, the main being that uranium can be produced there as a by-product. Two hundred and fifty-four samples from nine phosphate fields and one oil shale deposit overlying phosphorites were examined for U, P2O5 and organic matter. Statistical treatment of the normalized results (U/P2O5) showed that the different phosphorite fields probably represent different populations as far as uranium content is concerned. The fields showed significant differences in uranium content; there are fields relatively rich in uranium, like Zefa with a normalized mean of 5.9 ppm uranium per 1% P2O5, while others such as Saraf have only a mean of 3.5 ppm. These fields have about 28% P2O5 (Zefa) and 25% P2O5 (Saraf). It is suggested that the uranium concentration of the sea-water (interstitial water) was the dominant factor in uranium precipitation and concentration. Furthermore, on the basis of these findings, it should now be possible to choose and reserve the appropriate raw material to obtain the highest yields of phosphoric acid and uranium, and to use other phosphorites less rich in uranium for other purposes. (author)