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Quantitative Analysis of Cement by EDX-8000

High accuracy quality control analysis of cement is typically conducted using a wavelength dispersive X-ray fluorescence spectrometer. EDX instruments have become capable in recent years of analysis accuracy comparable to that of low-output wavelength dispersive type instruments. Not only do they offer such conveniences as the ability to analyze powders as they are, their range of applicability has greatly widened to include the analysis of such substances as cement. Here, we introduce the analysis accuracy obtained with pressure-formed cement standard powder samples using the new model EDX-8000.

♦ Standard Sample

NIST Certificate of Analysis Standard Reference Materials® Portland Cement

SRM 1880b, 1881a, 1884b, 1886a, 1887b, 1888b, 1889a

Table 1 shows the standard values.

Table 1: Standard Values
[mass%]
	SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO	SO₃	K₂O	Na₂O
1880b	20.42	5.183	3.681	64.16	1.176	2.710	0.646	0.091
1881a	22.26	7.060	3.090	57.58	2.981	3.366	1.228	0.199
1884b	19.30	4.851	2.937	61.31	4.740	4.034	0.957	0.278
1886a	22.38	3.875	0.152	67.87	1.932	2.086	0.093	0.021
1887b	19.59	4.911	2.471	61.15	3.624	4.599	0.961	0.288
1888b	20.42	4.277	3.062	63.13	3.562	2.634	0.658	0.136
1889a	20.66	3.89	1.937	65.34	0.814	2.690	0.605	0.195

♦ Sample Preparation

Pressure forming was conducted using a vinyl chloride ring (inner diameter 35 mmф), with a total pressure of 250 kN for 60 seconds. A photograph of the sample is shown in Fig. 1.

Fig. 1 - Pressure-Formed Briquette of Cement

♦ Calibration Curves

Analysis standard samples mentioned above, the calibration curve and accuracy (1σ) for each element are shown in Fig. 2.

Fig. 2 - Calibration Curves and Accuracy

♦ Lower Limits of Detection (L.L.D.)

The lower limits of detection calculated using the above calibration curves are shown in Table 2.

Table 2 Lower Limits of Detection (300 sec, 100 sec only for Fe2O3)
[mass%]
	SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO	SO₃	K₂O	Na₂O
L.L.D	-	0.0083	0.0022	-	0.0157	0.0066	0.0049	0.0159

♦ Repeatability

Using the above calibration curve method, the repeatability test results for SRM 1880b shown in Table 3 were obtained by simply conducting 10 repeat measurements. The X-ray fluorescence spectra for each measurement element of each sample are shown in Fig. 3.

Table 3 Repeatability for SRM 1880b (300 sec, 100 sec only for Fe2O3)

[mass%]

According to above characters, EDX-8000 can totally adapt to requirements of analyzing cement in actual production with high accuracy.

Source: ETA

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Quantitative Analysis of Cement by EDX-8000

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