This data sheet shows that the Epsilon 4 – a high performance energy dispersive X-ray fluorescence spectrometer – is capable of analyzing Na2O, MgO, Al2O3, SiO2, P2O5, S, K2O, CaO, TiO2, MnO, Fe2O3, SrO and BaO in un-ashed coal samples.
Coal is classified and valued according to its sulfur, phosphorous, volatile and ash content. The composition of ash can effect coal processing, handling and final usage. For example, coking coal used in the steel making industry requires coal with low sulfur and phosphorous content otherwise the quality of steel produced is adversely affected.
This application note shows that the Epsilon 4 – a high performance energy dispersive X-ray fluorescence spectrometer – is capable of analyzing Na2O, MgO, Al2O3, SiO2, P2O5, S, K2O, CaO, TiO2, MnO, Fe2O3, SrO and BaO in unashed coal samples.
Coal is classified and valued according to its sulfur, phosphorous, volatile and ash content. The composition of ash can effect coal processing, handling and final usage.
For example, coking coal used in the steel making industry requires coal with low sulfur and phosphorous content otherwise the quality of steel produced is adversely affected. In case of burning coal for the production of electricity, sulfur can be a major atmospheric pollutant. In addition to elemental sulfur (S), other elements routinely determined and expressed as oxides, include Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, MnO, Fe2O3 and SrO.
Measurements were performed using an Epsilon 4 EDXRF spectrometer, equipped with a 10 W, 50 kV silver anode X-ray tube, 6 filters, a helium purge facility, a high-resolution silicon drift detector, a spinner and a 10-position removable sample changer.
The coal samples were dried at 105 ˚C , ground in a tungsten carbide swing mill for 60 s, mixed with wax (8 g sample + 2 g wax) and pressed into pellets under 20 tons for 30 s. The pellet samples were put in standard sample holders and loaded into the Epsilon 4.
A number of commercially available coal standards, RMs and CRMs from Alpha Resources and from the SA Bureau of Standards were used to setup the calibrations. The details of the measurement conditions are given in Table 1. Sodium was analyzed using a region of interest (ROI). Figures 1 and 2 show the spectra obtained for the elements in a typical coal standard.
Table 1. Measurement conditions
Figure 1. Spectrum obtained using measurement condition 3 (Table 1) and showing the excellent resolution of the detector
Figure 2. Spectrum obtained using measurement condition 2 (Table 1)
Figure 3. Calibration graph of P2O5
Figure 4. Calibration graph of S
The calibration plots shown in Figures 3 to 4 demonstrate the strong correlation between the given concentrations and the measured intensities. Table 2 presents the RMS values of the calibrations, and the achievable detection limits.
One sample was measured 20 times consecutively. The averages and the standard deviations (1 sigma) are presented in Table 3.
This work clearly demonstrates the suitability of the Epsilon 4 EDXRF spectrometer for the quantitative analysis of P2O5, S, Na2O, MgO, Al2O3, SiO2, K2O, CaO, TiO2, MnO, Fe2O3, SrO and BaO in unashed coal samples. Accurate and precise results can be obtained in just 2 minutes.
