Fluorescent X-Ray Spectrographic Determination of Uranium in Waters and Brines

Abstract

In a search for a method sensitive to small concentrations of uranium in water and brine, a modification of a fluorometric method was adopted. The uranium is precipitated from the water or brine by the method of Smith and Grimaldi, and the ashed precipitate is analyzed by fluorescent x-ray spectrography. When an internal standard is required, yttrium nitrate is added. The sample holder of the Norelco x-ray spectrograph wTas modified to place the small precipitate samples in the most intense part of the beam from the molybdenum target x-ray tube. As little as 0.01 mg. of uranium, equivalent to 0.01 p.p.m. in a 1-liter water sample, can readily be measured, when the matrix contains no appreciable concentration of highly absorbing elements. The time for analysis is about 10 minutes per sample, when no internal standard is used, and about 15 minutes when the internal standard is used, exclusive of the precipitation process. THE recent public interest in the potentialities of oil-field waters as a source of uranium led to an investigation of methods for the analysis of waters and brines containing very small concentrations of this element. None of the methods described in the literature was entirely satisfactory, particularly for use in a study of a possible economical process for recovering uranium from water and brine solutions.

Water Analysis

“…The application of x-ray fluorescence analysis to the determination of uranium in waters and brines was reported by Kehl and Russell (128). The uranium is concentrated by Grimaldi's technique using aluminum phosphate coprecipitation.…”

X-Ray Emission Analysis of Plutonium and Uranium Compound Mixtures.

“…Yttrium (3,5, IS, IS), strontium (4, 10, 12, 13), and bromine (10,13) have been used in the analysis of either plutonium or uranium. The uranium-tothorium ratio has also been used (1,14), although in this case thorium was not added as an internal standard but was already present in the sample.…”

Trace Analysis by Combination of Ion Exchange and X-Ray Fluorescence. Determination of Uranium in Sulfate Effluents

“…Thus Pish and Huffman (5) first used the method to analyze uranium solutions directly, claiming an accuracy of 1% in the range studied by them (0.01 to l.OAf). Kehl and Russel (4), and also Flikkema, Larsen, and Schablaske (2), precipitated uranium from solution (U: 10_3M) and studied the precipitates by x-ray fluorescence. Wilson and Wheeler (9) studied the effect of using different x-ray targets when analyzing for uranium in solution, while more recently, Smithson,Eager,and Van Cleave (6) have applied the method for the direct determination of uranium in flotation concentrates and leach liquors.…”