Determination of Trace Elements in Lignite Ashes

Abstract

Two spectrographic methods for the quantitative determination of trace elements in lignite ashes and shales are described. The involatile elements are determined in a controlled atmospher of carbon dioxide gas that suppresses cyanogen bands, improves line to background ratio, and provides a more precise technique for the simultaneous determination of a large number of elements. Lutecium oxide in calcium carbonate and fused potassium sulfate (1 + 1) is used as the internal standard The volatile elements are determined in an ordinary d.c. arc, using a pellet technique to increase the limit of detection and rate of volatilization. Antimony and cadmium potassium sulfate are used as internal standards. Analyses of U. S. Geological Survey standard rock samples G1 and W1 show that the method can be extended to other silicate rocks. An additional application of the controlled carbon dioxide atmosphere is the determination of boron and gallium.