23 Mar 2018

XRF Fusion Beads for Cement Analysis | Spectroscopy Solutions

The chemical composition of cement influences performance. Elemental analysis can determine the quality of a cement and indicate which applications it is best suited to. XRF is the elemental analysis method of choice in the cement industry. This article outlines the best preparation method, using a Nieka Fusion Fluxer, supplied by Specac, for the XRF analysis of cement.

Specac only provides the Nieka Fusion Fluxers to customers from the United Kingdom.

The Nieka Fusion Flux range are the premium option for preparing fusion beads for sample analysis.

CLICK HERE FOR PRODUCT PRICING

Cement is a valuable and versatile material that is used for houses, roads, and infrastructure. It is not surprising, then, that cement is big business with the world's cement-makers making revenues of $250 billion per year.

The Composition of Cement Determines its Performance

Cement is made by heating a variety of materials including limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore. The result is a powder that mainly consists of oxides of calcium, silicon, aluminum, iron, magnesium and other trace elements including sodium and potassium.

A cement wall. The chemical composition of cement influences performance. Elemental analysis can determine the quality of a cement and indicate which applications it is best suited to.

Cement is useful because it acts as a binder. When cement is mixed with gravel or rocks and water is added, the mixture then hardens to form concrete. When water is added to cement CaO, SiO2, Al2O3, and Fe2O3 are hydrated to form calcium aluminosilicates and aluminoferrite hydrate, causing the cement to harden.

The performance of cement is influenced by its exact chemical composition and its mineral composition. For example, increased levels of MgO can cause weakness in the hardened cement. The nature of the raw materials used to make cement can lead to significant variations in the chemical composition of the final cement. Chemical analysis of cement can, therefore, be used to determine the cement quality and what applications a particular cement may be best suited to.

Chemical analysis is routinely used in cement manufacturing to test quarry sites, assess intermediate products, and for cement quality control. Those in manufacturing and construction may consider analyzing their cement to ensure that it is appropriate for the desired application and prevent costly repairs later.

Elemental Analysis of Cement

Elemental analysis of cement can tell us the proportion of each element present in the sample.  Although the mineral composition of cement can be more helpful in determining the quality and properties of cement, this can be difficult to measure. Elemental analysis is much easier to perform than mineral analysis, and the elemental ratios obtained can be converted into weight fractions of each oxide present in the sample. The ratios of oxides present in the sample can then be used to estimate the mineral composition of the cement.

We analyzed cement using Specac grinding and pressing equipment to prepare the sample.

Read our application note on the XRF analysis of cement samples

There are a wide range of elemental analysis methods available including gravimetry, atomic spectroscopy, inductively coupled plasma mass spectrometry, and X-ray photoelectron spectroscopy. However, many methods of elemental analysis require expensive instrumentation and complex methods. X-ray fluorescence (XRF) analysis provides versatile elemental analysis with relatively inexpensive equipment and simple procedures.

Studies have shown that with appropriate calibration and by using a reliable sample preparation method, XRF analysis can be as accurate as other elemental analysis methods like X-ray photoelectron spectroscopy. As a result, XRF is widely used in the cement industry for elemental analysis.

XRF is Widely Used for Cement Analysis

XRF is a versatile characterization technique that has become the method of choice for cement analysis.  XRF involves exposing a sample of cement to X-ray light, which excites the elements present in the sample. As the elements relax back to their ground state, they emit light.  The light emitted as the elements relax is characteristic to the particular elements present in the sample and measuring the fluorescence allows the exact chemical composition of the sample to be calculated. XRF analysis is non-destructive, quick, and simple to conduct, but correct sample preparation is essential to achieving accurate results.

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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What is XRF? Read about the technique here

Previously, pressed powder pellets have been used to conduct XRF analysis of cement samples. However, the use of alternative raw materials and additives in cement, combined with the development of new methods of sample preparation, means that pressed powder pellets are no longer the best option for XRF sample preparation of cement samples.

Fused Disc Preparation for Cement XRF

Producing fused discs from cement samples for XRF analysis offer several advantages over pressed powder pellets. Forming cement samples into fused discs involves mixing the sample with a flux (usually a lithium tetraborate or tetraborate/metaborate mixture) and melting the mixture in a platinum crucible at a very high temperature (900-1200 °C). The molten mixture can then be formed into a disc using a mold.

Preparing fused discs from cement samples does present some challenges. Finding the correct preparation strategy often involves trial and error to find the best additives, ratios, and fusion parameters.  For XRF analysis to be accurate, the fused disc samples must be prepared accurately, and the method must be repeatable and reliable. Preparation methods must be validated, and XRF measurements must be calibrated using reference materials with known elemental compositions prepared in the same manner as the cement samples.

The Nieka Fusion Flux range are the best option for preparing fusion beads for sample analysis.

CLICK HERE FOR PRODUCT PRICING

Using a sample preparation instrument such as a Fusion Fluxer from Specac can aid in developing an appropriate XRF sample preparation method and virtually guarantees reliable preparation and accurate XRF results. The Fusion Fluxers supplied by Specac are highly customizable, so appropriate preparation parameters are always within reach. Once a suitable preparation method has been determined, Fusion Fluxers from Specac offer reliable and repeatable preparation with automation, high-throughput, and ultra-high efficiency. Furthermore, the Fusion Fluxers distributed by Specac are easy to use and available at low-cost.

Fusion Fluxer features:

  • Lowest (safer) gas pressure, with natural or bottled gas option
  • Ultra-high efficiency & low cost of ownership
  • Efficient and customisable to your sample recipe
  • Real-time temperature monitoring by painted monitoring process

Conclusion | XRF Fusion Bead Preparation of Cement

The chemical composition of cement can vary widely and significantly affects performance. Elemental analysis of cement using XRF can provide peace of mind regarding the quality and suitability of a cement for a given application. Reliable, repeatable preparation of cement samples for XRF analysis is made easy with the premium quality Nieka Fusion Fluxer, available from Specac.

To learn more about what spectroscopy can do, check out #SpectroscopySolutions for more insights into the applications XRF and FTIR can fit.

Look up #SpectroscopyGuides for tips and tricks to help your analysis.

Also, check out our #SpectroscopySolutions presence on YouTube!

References and Further Reading

  1. ‘The global cement industry: Ready-mixed fortunes’ https://www.economist.com/news/business/21579844-worlds-cement-giants-look-set-recoverybut-will-it-be-durable-ready-mixed-fortunes
  2.  ‘Cement Materials Analysis’ http://www.claisse.com/en/medias/fichiers/nouvelles/claisse_cement_materials_analysis_accurate_total_solution_worldcement_xrf__35.pdf
  3. ‘Analysis of Chemical Composition of Portland Cement in Ghana: A Key to Understand the Behavior of Cement’ M. Bediako, E. Opoku Amankwah, Advances in Materials Science and Engineering, 2015.
  4. ‘Mineral and oxide composition of portland cement’ http://iti.northwestern.edu/cement/monograph/Monograph3_6.html
  5. ‘X-ray fluorescence analysis of iron(III), potassium and sulfur oxides in cements with a hyperbolic addition-dilution model and using a single multicomponent standard’ F. Bosch Reig, V. Peris Martinez,  J. V. Gimeno Adelantado,  S. Sánchez Ramos,  D. J. Yusá Marco, F. Bosch Mossi, Journal of Analytic Atomic Spectrometry, 1998.
  6. ‘XRF Fusion Beads | Electric & Gas Fusion Fluxers’ https://www.specac.com/en/products/sample-preparation/xrf/xrf-automatic-fusion-bead- machine