I have a limited amount of sediment to work with, and would like to sieve the sediments leftover from a loss on ignition analysis for a particle size analysis. I understand that organic matter is gone, so that would likely give me an underestimate of particle size, but am not familiar with changes to actual particles (fusing, etc.) at high temperatures.
550C is employed to remove ash content from any sample including yours. If you do have an analysis of ash content before and after heating you could get an idea about particle size and furthermore, if particle breaks in the temperature then you can expect to see a change and an increase in the finer particles are expected.
Herring's law tells you that there will be an increase in size as the fine particles fuse together with increased solid-solid diffusion. See slides 50 and onwards in:
October 2nd, 2013 The PSD, zeta potential, and rheology of ceramic materials and ceramic slurries/suspensions
https://www.brainshark.com/malvern/vu?pi=97328853&text=M021507
Dear Mr. Harrison,
as you mention that clay minerals (maybe Fe-Mn hydroxides, carbonates and phosphates too, either as particle or coating ?) are involved in the process a glance at the runs reported for thermochemical/ physical methods like the thermal analysis of DSC reveals that there are two critical zones which have implications on the variation of size and crystal structure of your particles. While the first zone around 100°C is less prominent indicative of the release of adsorbed water, the second one between 300 and 500°C has a stronger affect caused by the dehydroxylation and decarbonization mainly. I gave a rather general overview because of missing information of the precise composition of the mineral assemblage which is essential by quantity and quality.
Best regards
H.G.Dill
Just thinking again about this question. What changes might be expected at 350 C rather than the conventional 550C ?
To heat soil samples in this temperature, the organic matter (carbon) will be combusted. Depending on the mineral assemblage some weight losses will happens - Calcite and gibbsite are probably examples of mineral that will loss mass in this temperature. The literature about thermogravimetric analyses of clay mineral can give you a more complete overview.
- Badges
- Science topic
- Similar topics
- Geoscience
- Asia
- India