Analysis of slag samples

This data sheet demonstrates accurate elemental analysis of NaO, MgO, Al2O3, SiO2, P2O5, S, K2O, CaO, TiO2, MnO and Fe in slag samples.

Slag plays an important role as raw material in the cement and construction industry. In the cement industry it is used to reduce the amount of the expensive clinker component needed. XRF with its simple sample preparation and easy calibration maintenance is well suited to monitor slag compositions. 

Zetium Metals edition

Introduction

This data sheet demonstrates accurate elemental analysis of NaO, MgO, Al2O3, SiO2, P2O5, S, K2O, CaO, TiO2, MnO and Fe

in slag samples.

Application background

Slag is a byproduct of the iron and steel making processes. It is formed during the fluxing process used to remove the non-ferrous constituents of the blast furnace charge. Slag plays an important role as raw material in the cement and construction industry. In the cement industry it is used to reduce the amount of the expensive clinker component needed. XRF with its simple sample preparation and easy calibration maintenance is well suited to monitor slag compositions.

Instrumentation

Measurements were performed using the PANalytical Metals edition of Zetium, a fully integrated wavelength dispersive XRF spectrometer, complete with a X-Y sample handler and state-of-the-art software. It is engineered for excellence in terms of analytical and operational performance.

Configuration setup:

X-ray tubeRhodium anode 4 kW SST-mAX tube
Tube power60 kV/66 mA
GoniometerSi, AI, Ca, Fe, Mg, S, Mn, Ti, V, P, Cr, Na, K
MediumVacuum
Shielding plate37 mm
Sample holderStainless steel 37 mm aperture

Sample preparation and measurement details

Twelve commercially available blast furnace slag reference materials were used to set up a pressed pellet calibration. 10 grams of slag material were mixed to 1 gram of wax (binder) to make pressed pellets of 40 mm in diameter, pressing at 20 tons for 30 seconds.

Pressed pellets were loaded on the Metals edition of Zetium by using standard sample holders and measured to determine the concentration of Na2O, MgO, Al2O3, SiO2, P2O5, S, K2O, CaO, TiO2, MnO and Fe in slag samples. Each sample was analyzed for a total time of 222 seconds (roughly 4 minutes), measuring at the peak and background positions, see Table 1

Table 1. Application measurement time (in seconds)

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Results

Calibration plots for SiO2, Na2O, CaO and Fe are reported in Figures 1-4 and show the good correlation between certified concentrations and the measured intensities. Table 2 presents the RMS and lower limits of detection (LLD) of the individual element calibrations. Due to the influence of mineralogy and particle size on the accuracy of the analysis, the pressed powder pellet method of sample preparation is best suited when the calibration standards and the routine samples have the same characteristics and can be deemed ‘in-type’. As commercial reference materials were used, the quality of calibration can be further improved by using ‘in-type’ standards.

Table 2. RMS value for the pressed pellet calibration for slag analysis 

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Figure 1. Calibration line for SiO2 

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Figure 2. Calibration line for Na2O 

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Figure 3. Calibration line for CaO 

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Figure 4. Calibration line for Fe 

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Table 3. Analytical precision for sample BFS 3210 

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Conclusion

This study shows the capability of PANalytical's Metals edition of Zetium to analyze iron blast furnace slag samples as pressed pellets. The accuracy of results for major and minor elements - including Na content - makes the Metals edition of Zetium highly suitable for process control in the ferrous metal production.

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