Dear Mr. Abdul Aziz

Separation of different size of clay particles using sedimentation technique has to be done in different steps.

The method of choice is the settling tube method („Atterberg”) which is performed following the Stokes ‘Law.

1. Remove from your sample organic matter and soluble salt minerals by hydrogen peroxide and washing, respectively.

2. For mud-low or mud-free sample you can immediately dry the sample at approx. 70°C. For those samples enriched in mud pass your sample by wet-sieving to a set of sieves where the sand particles are retained as a function of mesh- or sieve size

3. The remaining fraction less than 20µm or 63µm is saved for the settling tube method. You must disperse the fine-grained matter, pour the slurry into the settling tube shake it and let it separate the coarser-grained matter from the finer one in a laboratory room under constant temperatures. In a view plain words, the finer and the purer the fraction you want to achieve the longer the time span necessary to attain these results. You can well separate the < 2µm fraction and even better the

Harald G. Dill Thank you so much sir for the answer.

I think hydrometer method is good, simple and accurate one if followed step by step carefully. As the clay reading should be taken after 2 hours from shaking.

Thanks @Doriana Vinci @Ali Zidan

Thanks dear Doriana

Can any please explain the exact time interval after shaking to separate silt+clay and then clay in 1000 ml volumetric cylinder.

exact time interval