Hello All -
I seek help finding the amorphous content of an iron ore sample. The problem might be my refinement. This sample was spiked with 9.4% corundum, and contains ~30% goethite, ~20% hematite, and a few percent quartz. My colleague conducted a refinement in JADE and got an estimate of 30% amorphous for this particular sample. I would thus expect to have an overestimated amount of of corundum in my sample, which would enable me to calculate the amorphous content. Instead, GSAS II gives me approximately the same weight% of corundum which was actually put into it (I get 9.1%). This gives a negative % amorphous content. In fact, in the GSAS archives, someone has already described the same problem I am experiencing: https://www.mail-archive.com/gsas-ii@mailman.aps.anl.gov/msg00015.html Details: In GSAS II I refine the sample using the phase fraction which gives the best fit, and convert these into weight percent using the equation from here: http://www.aps.anl.gov/Xray_Science_Division/Powder_Diffraction_Crystallography/5ParametersRecipes/5ParametersRecipes.pdf in which the weight percent is the phase fraction from GSAS II * Z * molecular weight. I then normalize the phases to equal a total of 100. I am using the second equation to find amorphous content in this paper: http://www.ccp14.ac.uk/solution/gsas/files/expgui_quant_gualtieri.pdf If anyone is interested in taking a shot, I'll be happy to send over data files or my current GSAS II project file. Thank you very much for your help in advance. Lindsay Young
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