protocol to determination of organic matter in the sand (temperature and time)
Mr.Youssef, what type of sand is it? Is it sandy soil? In the usual ignition methods, water is first driven off at 110o C and a weighed quantity of dried soil/sand is heated in a furnace for 8 hours at a temperature of 350-400o C.
Such prcedure is not so accurate as the method does not discriminate between the loss of organic matter on heating and loss of mineral matter such as carbon dioxide from carbonates and water and hydroxyl groups from clay minerals.However, in the range of 350-400 oC(better 375+_5o C),the loss of water from mineral structures may be small or negligible.However, you have to check for the presence of CaCO3 in the sand/soil which may interfere in the organic matter estimation.
Thank you Mr. Annangi Subba Rao for your answer, I found in
the standard nf in 12879 that the determination temperature
of the organic matter rate is 550 C. And in an other article
I found 450C for 2 hours
Mr.Youssef, the main concern is loss of mineral structural water at temperature higher than 450o C. According to Ball (1964) , the greatest part of the weight loss due to the clay mineral water occurs in the temperature range of 450-600 oC.So one can keep temperature of ignition below or at around 450o C.Keeling(1962) observed that by heating clays at 375o C for 16 hours destroyed over 90% of the carbonaceous material without loss of structural water.By increasing the ignition temperature one can reduce the duration of ignition but ignition temperature beyond 450oC may not be prepferred.I do not have idea of the amount of structural water in your sand material.
Ball, D.F. (1964) J.Soil Sci.,15,84.This paper can be consulted for more details.
Keeling, P.S. (1962) Clay Miner.Bull.,28,155.
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