Hi,
I am interested in quantifying the abundances of different phases of clay minerals of marine sediments using XRD analysis. Any suggestions regarding the detailed method/software will be appreciated.
Thanks!
Anupam
Hi Anupam,
If you have a well qualitative characterization of the mineral phases, you can try quantification of mayor phases by using the Rietveld method.
Good luck
Yes, Rietveld method will do for quantification. But clay minerals should be first characterised by normal diffraction, followed by glycolation, heat-treatment etc. depending on the type of clay minerals.
first you have to do XRF to determine major phases in your sample but if there is an important organic matter you must calcined your sample then thanks to Highscore you can get the answer.
You can return back to the article:
XRD- based quantitative analysis of clay minerals using reference intensity ratios, mineral intensity factors, Rietveld, and full pattern summation methods: A critical review. 2018.
Yes, you can use the Rietveld method to quantify the different percentage of the minerals. First, you need to scan the samples at a low scanning speed. The major clay minerals have the peak less than 10 degrees, so it is better for you to scan from 5 degrees.
After that, two steps :
Phase identification : you can go to http://www.crystallography.net/cod/search.html find .cif file for the phases. Download Vesta https://jp-minerals.org/vesta/en/download.html , use it to simulate XRD pattern for the phases, and compare them with your data. If the (at least) 3 majors peaks of it match your sample, it likely exists in your sample, otherwise, just trash it.
Rietveld Refinement
You do quantification of each phase using Fulllprof https://www.ill.eu/sites/fullprof/php/downloads.html or maud http://maud.radiographema.eu/ . You can find many tutorials on youtube
You can perform Rietveld analysis using GSAS-EXPGUI free software. There is a manual on the internet and it is very user friendly.
You can use Jade to do phase analysis, and then determine the relative content of each phase according to its strength, but this software needs to be learned, and the processing results are not very accurate.
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