8. Test for the presence of lime
The clay to be tested has to be taken out from the bulk supply by ‘Cone and Quarter’ method - the sample to be prepared is around 1 kg. From this master sample take out about 100 gms and soak it in distilled water about 1 litre. After soaking, […]

7. Test for Soluble Salts (..contd)
b) Determination of Sulphate
The clay to be tested has to be taken out from the bulk supply by ‘Cone and Quarter’ method - the sample to be prepared is around 1 kg. From this master sample take out about 100 gms and soak it in distilled water about 1 litre. […]

7. Test for Soluble Salts
a) Soluble Chlorides
The clay to be tested has to be taken out from the bulk supply by ‘Cone and Quarter’ method - the sample to be prepared is around 1 kg. From this master sample take out about 100 gms and soak it in distilled water about 1 litre. After soaking, […]

6. Test for fired water absorption
The degree of water absorption is the measure of the vitrification of a fired clay body. This is determined by the following procedure

Make bars of 5X5X10 cm. Minimum 3 bars has to be made.
Fire the bars and weigh the fired bars.
Boil the fired bars in water for 2 hours.
Dry the […]

5. Test for Total Shrinkage
Total fired shrinkage may be calculated by using the following formula. In ceramic applications the total shrinkage is very important to find out the final dimension of the article. The drying shrinkage gives the information about the shrinkage behaviour of the clay article during drying operation which is very important for […]

4. Test for firing Shrinkage
Firing shrinkage is normally determined on samples fired to various different temperatures. This gives an idea of progressive compaction of the clay with advancing temperature.

Fire the dried bars made for the drying shrinkage tests.
After firing measure the mass of length on the fired bar.
Find out firing shrinkage using the following formula

% […]

3. Test for drying shrinkage
The amount of shrinkage is a very important charcteristic of any clay especially in the slip casting process. The clay shrinks both at drying and firing. The drying stage shrinkage is called drying shrinkage and it is tested as linear shrinkage as follows.

Prepare few bars of the following dimension i.e. 14 […]

2. Test for water of plasticity.
This test finds out the amount of water required to make the clay plastic and workable. The more water the clay requires to become plastic, the finer its grain structure and hence apt to shrink more on drying.
a) Thoroughly dry the clay sample and pulverize it so that it will pass through […]

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 […]

The data collected from the tests listed in previous article, together with experience gained from working samples of the clay should give an informed estimate value of the clay. The chemical analysis report and the physical analysis report together should be used for finding out the suitability of the clay.
Once the individual clay properties are […]