Presentation - Combined LA-ICP-MS and SEM-EDX analyses for spatially resolved major, minor and trace element detection in cement clinker phases

Abstract

This study combines 2D element mappings obtained by laser ablation with inductively coupled plasma mass spectrometry (LA-ICP-MS) and energy dispersive X-ray spectrometry (EDX) in the scanning electron microscope (SEM) to analyse the chemical composition of cement clinker phases. It is revealed that this approach enables to determine the major and trace element concentrations in phases like alite, belite and the interstitial phase of real Portland cement clinker. A protocol is shown how to record and subsequently register both datasets as such, that the combined analysis significantly broadens the output of the individual measurements. The low detection limits of LA-ICP-MS delivers trace element concentrations and the high spatial resolution and analytical accuracy of SEM-EDX identifies the clinker phases.
Results show that Ba, K, V, and Rb are preferentially incorporated into belite. This allows to study the influence of minor and trace elements on the stabilisation and reactivity of clinker phases.

Full text

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Combined LA-ICP-MS and SEM-EDX analyses for
spatially resolved major, minor and trace element
detection in cement clinker phases
Florian Kleiner, Marco Decker*,
Christiane Rößler, Harald Hilbig*,
Horst-Michael-Ludwig
* TU München, Center for Building Materials

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
•The chemical composition of cement clinkers determines the
reactivity and properties of concrete.
•Minor (< 1.0 up to 2.0 wt.-%) and trace elements (< 0.1 wt.-%) also
influence the clinker reactivity.
•They originate from the raw materials and the use of alternative fuel for
the calcination process.
•It is challenging to identify, in which clinker phases the minor and trace
elements are incorporated.
Motivation

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
•EDX
+Good spatial resolution
(< 0.5 µm/px raw scan, < 1 µm/px segmentation)
-Detection limit and accuracy of 0.1 wt.-%
•LA-ICP-MS
+Very low detection limits (few atoms, mass
spectroscopy)
-Low spatial resolution (6 x 6 µm ablation area)
-Line ablation leads to overlaps and “not square
pixels”
oNoisy results and therefore hard to segment data
Analytical methods

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
LA-ICP-MS
source: Günther, 2005, 10.1016/j.trac.2004.11.017
https://www.geowiss.uni-mainz.de/la-icp-ms-labor/

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Laser Ablation is a destructive method
raw data available: 10.5281/zenodo.5679544

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Laser Ablation is a destructive method
raw data available: 10.5281/zenodo.5679544

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Laser Ablation is a destructive method
•LA-ICP-MS has to follow the EDX analysis
•Conductive layers should be removed
•Ablation depth depends on the material
(works in clinker due to a comparable durability)
•Elements are measured sequentially
•Multiple ablation runs necessary
•Signal originates from slightly different material depths
•Ablation size should be calibrated using follow-up SEM images

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Combination of both methods
Goal
Combination of
high-resolution phase segmentation (EDX)
and
low detection limits of LA-ICP-MS
Locate minor and trace elements
within cement clinker phases

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Specimen - Cement clinker grain

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Workflow –1. polishing and area selection
raw data available: 10.5281/zenodo.5742586

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Workflow –2. BSE imaging
raw data available: 10.5281/zenodo.5742586

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Workflow –3. EDX mapping
raw data available: 10.5281/zenodo.5742586

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Workflow –4. Laser ablation, followed by SEM
Conductive layers (C/Au)
have to be removed
raw data available: 10.5281/zenodo.5742586

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Workflow –5. alignment of LA-ICP-MS dataset
raw data available: 10.5281/zenodo.5742586

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Workflow –6. align EDX + LA-ICP-MS dataset
raw data available: 10.5281/zenodo.5742586

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Area 2
raw data available: 10.5281/zenodo.5742586

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Area 3
raw data available: 10.5281/zenodo.5742586

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Spot analysis
•LA-ICP-MS also profits from a larger spotsize (ø 23 µm)
•Better signal
•More elements
•Works good for large, homogeneous
phases like belite.
•Small phases (C3A, C4AF), can’t be
measured.
•Alite is also hard to measure, due to
inclusions of other phases.

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Calibration
Detection limit 0.1 wt.-%
•The raw ICP-MS results are uncalibrated and have to be calibrated using standard materials.
•There exists no real “standard material” to calibrate the LA-ICP-MS for all trace elements.
•The mean signal of a LA-ICP-MS
mapping is assumed to be the
same as the mean chemical
composition!
•However, the EDX analysis shows,
that the selected area might not
be fully representative!

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
Results
Comparison of the EDX results. Belite, 3 mapped areas.
Comparison of the LA-ICP-MS results. Belite, 3 mapped areas.
Detection limit 0.1 wt.-%
•Low standard deviations due
to noise.
•The deviation between the
mean measurements is
relatively high.
•High standard deviations due
to noise.
•The deviation between the
mean measurements is
relatively low.

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
LA-ICP-MS differences between phases

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
•It is possible to combine LA-ICP-MS and EDX datasets with good
accuracy.
•This allow to locate the incorporating phase of minor and trace
elements.
•Na, Ti, Mn are predominantly incorporated in C3A and C4AF
•K, V, Ba, Rb are predominantly incorporated in belite
•Improvements are possible by using a smaller laser and different mass
spectrometers, which allow to measure elements simultaneously.
Conclusion

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
alite belite
Mg
Na
C3A and C4AF
Appendix: Data fit

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
alite belite
Si
Al
C3A and C4AF
Appendix: Data fit

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
alite belite
Ca
K
C3A and C4AF
Appendix: Data fit

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
alite belite
V
Ti
C3A and C4AF
Appendix: Data fit

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
alite belite
Mn
Cr
C3A and C4AF
Appendix: Data fit

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
alite belite C3A and C4AF
Zn
Fe
Appendix: Data fit

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Florian Kleiner, Kombination von EDX & LA-ICP-MS
26.04.2022
alite belite
Ba
Rb
C3A and C4AF
Appendix: Data fit

www.uni-weimar.de
floriankleiner.de
github.com/kleinerELM
researchgate.net/profile/Florian-Kleiner
www.uni-weimar.de
floriankleiner.de
github.com/kleinerELM
researchgate.net/profile/Florian-Kleiner
Thank you for your attention!
doi: 10.1016/j.cemconres.2022.106875
In
Cement and Concrete Research
Closed Access (sorry 🙄)