Chemical Analysis of Coal by Energy Dispersive X-Ray Fluorescence Utilizing Artificial Standards

Abstract Accurate determinations of the elemental composition of coal by classical methods can be quite difficult and are normally very time consuming. X-ray fluorescence utilizing the powder method, however, has the ability of providing accurate and rapid analyses. Unfortunately, well characterized standards, although available, are not plentiful. In addition, the durability or stability of ground and pelletized coal samples is poor resulting in deterioration with time. As a result, artificial coal standards were prepared from certified geological materials by fusing in lithium-tetra-borate in percentages approximating expected ash contents and compositions in coal. Since the lithium-tetra-borate comprises about the same percentage of the standard as does the carbon, hydrogen, and oxygen in coal, the ground and pelletized coal sample can be assayed against the fused calibration curves by compensating for the differences in the mass absorption coefficients of the two matrices.