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Quantitative Analysis of Cement by EDX-8000 (SRM 1880b, 1881a, 1884b, 1886a, 1887b, 1888b, 1889a)

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.

  • Sample

NIST Certificate of Analysis Standard Reference

Materials® Portland Cement

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

Table 1 shows the 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

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

Lower Limit of Detection (LLD)

-

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.

Fig. 3 X-Ray Fluorescence Spectra of Measured Elements

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

[mass%]

 

SiO2

Al2O3

Fe2O3

CaO

MgO

SO3

K2O

Na2O

1

20.09

5.032

3.615

64.12

1.088

2.729

0.622

0.100

2

20.05

5.031

3.609

64.15

1.087

2.740

0.621

0.098

3

20.04

5.043

3.615

64.18

1.087

2.736

0.612

0.107

4

20.01

5.022

3.625

64.16

1.089

2.738

0.616

0.105

5

19.96

5.038

3.618

64.18

1.148

2.744

0.620

0.100

6

20.02

5.045

3.625

64.18

1.094

2.744

0.615

0.114

7

20.11

5.052

3.630

64.18

1.157

2.743

0.616

0.110

8

20.09

5.037

3.628

64.17

1.174

2.740

0.619

0.112

9

19.98

5.032

3.631

64.17

1.101

2.741

0.616

0.109

10

20.14

5.040

3.614

64.21

1.158

2.745

0.621

0.100

Average

20.05

5.037

3.621

64.17

1.118

2.740

0.618

0.105

Standard Deviation

0.059

0.008

0.008

0.025

0.036

0.005

0.003

0.006

Coefficient of Variation [%]

0.30

0.17

0.22

0.04

3.2

0.17

0.52

5.5

Source: ETA

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