Best references for the QPA of Portland cement

Fawcett, T. G.; Blanton, J. R.; Kabekkodu, S.; Blanton, Thomas N.; Lyza, J.; Broton, D.

doi:10.1017/s0885715622000215

Cited by 2 publications

(10 citation statements)

References 12 publications

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“…Reliable QPAs for slags are achieved using the block refinement method laid out in Fawcett et al (2022), where restrictions on certain parameters, such as temperature factors and crystallite sizes can be manually refined. This approach led to the best refinement results of this laboratory data.…”

Section: Discussionmentioning

confidence: 99%

“…The main refinement technique used in this research was the "Modified Rietveld" block refinement using JADE Pro (MDI, 2023), as it seemed to best handle the various crystallite sizes found in this material. Whole pattern RIR was performed in the SIeve+ module in PDF-4+ (Fawcett et al, 2015(Fawcett et al, , 2020(Fawcett et al, , 2022 to validate the block refinement method. The full, automated Rietveld refinement option in JADE Pro was tested periodically during this project by T. Fawcett, which showed correct identification of phases >10 wt%, but false positives for most, if not all, remaining phases.…”

Section: Quantitative Phase Analyses and Data Analysesmentioning

confidence: 99%

“…Before adjusting any other intensity-based parameters, crystallite sizes were refined for all phases >1 wt%, excluding iron oxides like wustite, magnesioferrite, jacobsite, hematite, and srebrodolskite, following the protocol of Fawcett et al (2022). s0 and p0 were also refined at this time, as s0 refined the peak shape to a typical pseudo-Voigt profile, and p0 refined the calibrated instrument parameters for the Rigaku MiniFlex from a previously developed instrument profile curve (IPC).…”

Section: Bof Example Phase Refinementmentioning

confidence: 99%

“…All these issues related to the proper QPA of slags compound, forming a large quantity of potential variables that could lead to an unrealistic refinement. As mentioned in Fawcett et al (2022), “A difficulty of QPA by Rietveld analysis is the large number of potential variables that can be refined using 12 structures, multiple supercells, polymorphs, and variable doping at atomic sites.” Like in cements, having a large group of phases in a material, and therefore having more refinable parameters, could lead to an unrealistically better fit during Rietveld refinement. The analyst must be cautious to avoid impractical refinements and ensure that there is enough information in the data to support their analysis (Peterson et al, 2006, 16).…”

Section: Introductionmentioning

confidence: 99%

“…Table I from Best References: comparison of methods used in quantitative phase analysis(Fawcett et al, 2022).…”

mentioning

confidence: 99%

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Challenges of quantitative phase analysis of iron and steel slags: a look at sample complexity

Lyza¹,

Fawcett

Page³

et al. 2023

Powder Diffr.

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Quantitative phase analysis (QPA) of slags is complex due to the natural richness of phases and variability in sample composition. The number of phases frequently exceeds 10, with certain slag types (EAF, BOF, blends, stainless) having extreme peak overlap, making identification difficult. Another convolution arises from the variable crystallite sizes of phases found in slag, as well as the mixture of crystalline and amorphous components specific to each slag type. Additionally, polymorphs are common because of the complexity of the steelmaking and slag cooling processes, such as the cation-doped calcium aluminum silicate (Ca3Al2O6, C3A, Z = 24) supercell in LMF slag. References for these doped variants may not exist or in many cases are not known in advance, therefore it is incumbent on the analyzer to be aware of such discrepancies and choose the best available reference. All issues can compound to form a highly intricate QPA and have prevented previous methods of QPA from accurately measuring phase components in slag. QPA was performed via the internal standard method using 8 wt% ZnO as the internal standard and JADE Pro's Whole Pattern Fitting analysis. For each phase, five variables (lattice parameters, preferred orientation, scale factor, temperature factor, and crystallite size) must be accounted for during quantitation, with a specific emphasis on not refining crystallite sizes for iron oxides and trace phases as they are inclined to over-broaden and interact with the background to improve the goodness of fit (R/E value). Preliminary investigations show somewhat reliable results with the use of custom file sets created within PDF-4+ specifically targeted toward slag minerals to further regulate and normalize the analysis process. The objective of this research is to provide a standard protocol for collecting data, as well as to update methodologies and databases for QPA, to the slag community for implementation in a conventional laboratory setting. Currently, Whole Pattern Fitting “Modified” Rietveld block refinement coupled with the addition of a ZnO internal standard gives the most accurate QPA results, though further research is needed to improve upon the complex issues found in this study of the QPA of slags.

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Section: Discussionmentioning

confidence: 99%

Section: Quantitative Phase Analyses and Data Analysesmentioning

confidence: 99%

Section: Bof Example Phase Refinementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Table I from Best References: comparison of methods used in quantitative phase analysis(Fawcett et al, 2022).…”

mentioning

confidence: 99%

See 3 more Smart Citations

Challenges of quantitative phase analysis of iron and steel slags: a look at sample complexity

Lyza¹,

Fawcett

Page³

et al. 2023

Powder Diffr.

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An Improved Model for Biogenic Ammonium Urate

Thornton

Fawcett

Kaduk

et al. 2023

Crystal Growth & Design

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The pathological crystallization of ammonium urate inside the urinary tract is a well-documented medical condition; however, structural studies of the biogenic material have proven challenging owing to its propensity to precipitate as a powder and to exhibit diffraction patterns with widely varying intensities. Using block Rietveld refinement methods of powder diffraction data, here we identify ammonium urate hydrate (AUH) as a likely component in natural uroliths. AUH has a planar 2-D hydrogen-bonded organic framework of urate ions separated by ammonium ions with water molecules residing in bisecting channels. AUH is stable up to 150 °C for short time periods but begins to decompose with prolonged heating times and/or at higher temperatures. Changes in the solid-state structure and composition of synthetic material over a temperature range from 25 to 300 °C are elucidated through thermogravimetric and spectroscopic data, combustion analysis, and time-resolved synchrotron powder X-ray diffraction studies. We contend that biogenic ammonium urate is more accurately modeled as a mixture of AUH and anhydrous ammonium urate, in ratios that can vary depending on the growth environment. The similar but not identical diffraction patterns of these two forms likely account for much of the variability seen in natural ammonium urate samples.

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Best references for the QPA of Portland cement

Cited by 2 publications

References 12 publications

Challenges of quantitative phase analysis of iron and steel slags: a look at sample complexity

Challenges of quantitative phase analysis of iron and steel slags: a look at sample complexity

An Improved Model for Biogenic Ammonium Urate

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