Cement – composition, structure and fineness – Q&A

by Alon Vaisman

In the presentation, we described where and how various technologies fit into the value chain of cement production from quarry to finished grinding and gave practical examples of value and return on investment for the users.

If you missed the webinar, you can view a recording on our website.

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Below is a list of answers to the questions asked at the event.

Q: How long does one measurement take? How much sample is needed for one measurement?

This depends on the type of materials, but for clinker, you can assume typically about 5 minutes (both for XRF and XRD). The amount of sample is in the order of grams.

Q: Can you elaborate a little more about the sample preparation? I have not done XRF by myself. Please sum up more reasons for fused beads compared to pressed tablets than “going beyond”!

There is a whole lot to say about sample preparation and I encourage you to have a look on our website, where we have a number of application notes on this topic.

In general, there are two ways of doing sample preparation: using fused beads or pressed pellets. For XRF the advantages of using fused beads are that you eliminate the mineralogical effect. Elements bound in different minerals can give a different contribution to the spectrum. With fused beads, you reduce the particle size effect and you reduce absorption/enhancement effects due to the dilution you apply. Fused beads give for XRF analysis more reliable results than pressed pellets, but it cannot be used for XRD measurements.

The advantages of pressed pellets is the ease of sample preparation, generally lower cost and you can use this type of preparation for both XRF and XRD.

Q: On your preparation method, what is the best ratio that does you recommend sample to flux to get an accurate reading on the x-ray?

This depends on the material you analyze, but typically the ratio is between 1:5 to 1:30, where 1:10 is the most common ratio.

Q: You mention the effect of Ferrite related to longer scale reactivity of clinker, can you explain a little more?

All the clinker phases alite, belite, aluminate and ferrite contribute to strength, hydration properties as well as color. It goes a little beyond the scope of the webinar to explain the details. A good reading material can be found on Understanding Cement or the cement engineers’ handbook.

Q: I am a current user of HighScore for Rietveld refinement on a clinker. I have been asked to start working on cement. I am having troubles quantifying fly ash (amorphous material). Are there any courses/guides out for quantifying fly ash content?

The method to deal with the amorphous material or poorly crystalline material is called PONCKS. This methodology can be set-up in our HighScore Plus software. We give training on these topics.

Please do not hesitate to This email address is being protected from spambots. You need JavaScript enabled to view it. if you have any further questions that haven’t been answered above!