WDXRF Method Improves Light Element Quantification in Coal Analysis

In a recent study published in Spectrochimica Acta Part B: Atomic Spectroscopy, a novel X-ray fluorescence (XRF) method was combined with partial least squares (PLS) regression to determine light element content in coal. Carbon, oxygen, hydrogen, and nitrogen were studied. The researchers executing the study collected information that could be utilized by researchers to improve semi-quantitative methods of XRF based on fundamental parameters (FP) (1).

black coal in the hands, heavy industry, heating, mineral raw materials | Image Credit: © martingaal - stock.adobe.com

XRF analysis has been regularly used in coal analysis. However, the technique alone does have specific limitations. For example, traditional XRF analysis has limitations in quantifying specific light elements (1). To overcome the limitations of traditional XRF analysis, the researchers presented a way to improve on the technique by using wavelength dispersive XRF (WDXRF) scattering spectra to quantify carbon, oxygen, hydrogen, and nitrogen in coal samples (1).

The research team prepared a set of 25 coal samples for analysis. These samples underwent precise grinding, drying, and weighing, followed by compression into reusable steel rings (1). The spectra of coherent and incoherent scattering of the primary X-Ray radiation were then analyzed, revealing hidden differences that were previously unexploited for quantification of these crucial elements (1).

By utilizing PLS regression, the team createdcalibration curves for the concentrations of carbon, oxygen, hydrogen, and nitrogen in coal samples (1). Only WDXRF was needed to determine these elemental concentrations, and researchers did not need to employ special crystal analyzers (1). The researchers also discovered that the quantification of hydrogen can be done indirectly through scattering, despite it not having the characteristic spectral lines (1).

The results of this study enhance the semi-quantitative techniques of XRF based on fundamental parameters. This holds promise for improving coal quality assessment, as well as aiding in a better understanding of coal composition and its environmental implications.

This research determined that the differences in scattering spectra carry information about the concentration of light elements. They also concluded that the PLS model improves FP analysis for coal samples with high light element content.

Reference

(1) Sverchkov, I. P.; Matveeva, V. A.; Chukaeva, M. A. Determination of carbon, oxygen, hydrogen and nitrogen content in coals using WDXRF scattering spectra. Spectrochimica Acta Part B: At. Spectrosc. 2023, 207, 106738. DOI: 10.1016/j.sab.2023.106738