Довольно IMHO взвешенные ответы в ResearchGATE
How to get the clay-size part(<2μm) from the soil sample?
Mathias H. Köster · 11.39 · Technische Universität München
Check if you have high amounts of organics or iron minerals. If yes: remove them prior to further sample processing with hydrogen peroxide (there are several approaches so you ought to check the literature) and EDTA or AAO for the iron minerals (again, the exact approach can be varied).
If there are neglibible organics and iron minerals, and after the above treatment, dispers the soil in water (keep the pH around neutral) and separate the < 2.0 um fraction by sedimentation in Atterberg cylinders or use centrifugation. Some soils have few true clay minerals, so it might be useful to use the < 6.3 fraction instread.
Settling times follows the Stokes law based on equivalent diameter, density, temperature, etc. Google provides plenty of examples.
2 / 0 · 2 days ago
Kenneth M Towe
Kenneth M Towe · 245.74 · Smithsonian Institution
Mathias... one caveat? Hydrogen peroxide may not remove all organics, esp. kerogen-like materials. Dithionite works well on iron oxides. But, surely there is someone he can speak with who has done some lab work on clays and soils?
2 days ago
Mathias H. Köster
Mathias H. Köster · 11.39 · Technische Universität München
Yes, Kenneth, you are right! I did not have that problem, yet, so I did not think of it.
1 / 0 · 2 days ago
Sachin Kumar Tripathi
Sachin Kumar Tripathi · 5.78 · Geological Survey of India
Kenneth sir, yes Mathias is right when you have removed all the organic material then dry and weigh it, you can get the actual content of the soil. So sieve it without having any advance equipment. Less than 63 μm will provide you silt size fraction and further you can go for pipetting (<2μm largest particle of colloidal, in this case, you leave your samples for more than 8 hours or less and then collect the colloidal water, in such case you may have chance to get the desired result). Otherwise nowadays so many sophisticated instruments are available who can easily separate the clay without doing all those things, as mentioned above by Mathias.
It doesn't matter what it is, he only need to separate the clay fraction from the soil. After analysis he would have better idea about all the available content within it.
you may check this link
http://nvlpubs.nist.gov/nistpubs/jres/13/jresv13n2p245_A2b.pdf http://faculty.nres.illinois.edu/~jstucki/Laboratory%20Methods/Clay%20fractionation_jws.pdf Regards,
2 days ago
Katerina Kovarova
Katerina Kovarova · 4.68 · Czech Technical University in Prague
I saparated clay minerals from finely crushed sandstone using ultrasonic bath followed by centrifugation. I did not deal wit the organic matter.
2 days ago
Abdelouahab Knidiri
Abdelouahab Knidiri · 6.14 · Cadi Ayyad University
Hi to all,
In general, separating clay fraction from sediments requiere the implementation of sevral operations ordered as follow:
1- According to the samples hardness: Crushing with a mortar or a grinder
2- Desintegration: practiced in an Erlenmeyer with a deionised watter, the coarse material of the bottom can be removed by successive decantations.
3- Decarbonation and washing: performed by successive washing with deionized water after dissolution of carbonates from the crushed samples with 0.2 N HCl (use a Ph meter to control the acidity deccrease after each washing operation until it becomes neutral) . The size-fraction (<2 mm) can be separated by sedimentation according to Stoke’s law using the procedures described by Thierry Holtzapffel ( LES MINERAUX ARGILEUX, Préparation; Analyse diffractométrique et détermination, 1985. SOCIETE GEOLOGIQUE DU NORD, Publiication n°12).
This method gives reliable results. However, as the colleagues have mentionned, special cases may occur (organic matter, rate of calcite, dolomite, etc.); The above document should be helpful for you.
Best regards
https://www.researchgate.net/post/How_to_get_the_clay-size_part2mm_from_the_soil_sample?tpr_view=I7pT1MolyKSsiR42jZ8jrse8HY1N3wkumBVF_1
Отправлено: 24.11.16 08:19. Заголовок: Про определение глинистости в лаборатории
