Short routine direct method for the fluorimetric determination of uranium in phosphate rocks

A short routine direct fluorimetric procedure for the determination of up to 0.06 percent uranium in phosphate ricks is described. The procedure employs a simple acid leach for preparing the solution, and the uranium is determined directly on a 1.8-mg aliquot. The results obtained by using this simply procedure on several thousand samples are discussed. The quenching of the uranium fluorescence by foreign elements was found to be negligible, for all practical purposes, and results on western phosphates may be corrected by using an empirically determined quenching factor.