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1. Take the <2 µm clay fraction, this should be rinsed and free of any treatments.
2. In centrifuge tube, add ~20 mL of 1N HCl.
3. Vortex the sample to completely dislodge all material before pouring sample into a 100 mL beaker, add stir bar once sample is in place.
4. Set hotplate to 300°C (boiling point of HCl is ~101ºC, but in order to maintain a continuous boil the hotplate needs to be much hotter)
5. Set the stir RPM below 100, this is only to keep the material suspended within the HCl
6. Start time once the samples have come to a complete boil, leave for 2 hours — add more HCl as necessary (DO NOT let the sample go dry and burn)
7. Once the sample has boiled for 2 hours, turn off the hot plate and allow sample to return to room temperature before pouring beaker contents back into a clean centrifuge tube. Rinse beaker with DI water to collect all material
8. Centrifuge down for 15 mins at 1500 rpm, decant acid and rinse with 25 mL nanopure (DI) water. Repeat the washing cycle 3 times.
9. After samples has been washed 3 times and is free of HCl, centrifuge for 60 mins at 3000 rpm

Troubleshooting

If the dismembrator does not start the program after pressing the button "Start", i.e., if the screen still displays 'P  0' (Power=0) and not 'rdy' (Ready), press the "Reset" button, then press "Test" and finally "Start". The dismembrator should clear the error and starts the program normally. Power on the display screen should be 'P  11' when a sample is vibrating. The cause of this error is unknown and happens when the dismembrator is turn on.

References

Jackson, M.L., 1956. Soil Chemical- Analysis Advanced Course by Hsueh-Wen Yeh, Hawaii Institute of Geophysics, 1980.
Moore, D.M., and Reynolds, R.C., Jr., 1989. X-ray Diffraction and the Identification and Analysis of Clay Minerals: New York (Oxford University Press).

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