X-Ray Fluoresent Determination of Rare Earth Elements in Carbon and Low-Alloy Steel

Abstract

In a recent study to improve the properties of steel by the addition of rare earth elements, a need arose for an accurate analytical method of these elements. An investigation was undertaken to determine 4 rare earth elements (La, Ce, Nd, and Pr) in the range of 0.005 to 0.15% by the X-ray fluorescent technique.
In the absence of reliable standards, the glass-bead technique for odd samples such as drillings was developed. Rare earth elements were precipitated as the fluorides after dissolving 5g of the sample in sulfuric acid, and the filtered fluorides followed by ignition to oxides were mixed with sodium tetra borate and melted to prepare glass-bead.
The glass-bead method provided for precision less than 2% of the amount present. A good agreement was obtained between the chemical and X-ray results.
The advantages of the method are the facility of the construction of a calibration curve by using chemical reagents, the absence of interelemental effects because of the separation of rare earth elements, and the versatility to be applicable to other materials with minor modifications.
The standard samples of low-alloy steel were furthermore prepared for the direct metal disk technique and a conventional procedure was taken with satisfactory results.