1. Test for excess sand or other mineral fragments.
Take 100 grams of clay to be tested. Dry it in an oven at 100C until it dries. Powder the dried clay and pass it through a sieve shaker machine which contains various sieves starting from coarse to fine. After sieving, take out each fraction of the clay from different sieves. Weigh each fraction and report as sand/other impurities present in the clay.
Normally for practical purpose, the residue obtained over 200-mesh has to be considered as sand and other impurities. In some cases this will be on 300-mesh also. More the sand on 200-mesh, inferior the clay for usage in sanitaryware.
To be contd……
