Kaolin Spergau




BGMN Application: Standard Sample Kaolin Spergau

Author:
Dr. R. Kleeberg
Sample preparation:
- hand milled in an agate mortar, sieved < 20 um
- filled without pressure in an Al- sample holder (thick sample)
- minimization or preferred orientation by sandpaper
Measurement:
- URD-65 (SEIFERT-FPM GmbH) Cu long fine focus tube;
- secondary monochromator
- angular range 5 .. 78 degree, 0.03 degree step size

Phase	Lattice parameters	Preferred orientation	Peak model	Special features
quartz	2	-	crystallite size	-
kaolinite	6	6	crystallite size; microstrain	6 disordering parameters
muscovite 2M1	4	6^th order; automatic reduced to 2^th order	crystallite size anisotropic	site occupation for K⁺

Table 1: Phase parameters for calculation

Results:
R_wp = 11.7 %; calculation time: 1 h 45 min;

Phase Nominal content Rietveld content

quartz 15.0 16.9

kaolinite 71.6 75.4

muscovite 2M1 12.8 (illite) 7.7

Table 2: Calculation results (weight %)
Remark:

the calculated mica concentration is too low because substantial more illite 1M and 1Md than muscovite is contained in the sample; consequently quartz and kaolinite are overestimated

Figure 1: Observed, calculated and difference Cu-K-alpha powder pattern for the kaolin Spergau sample

BGMN Application: