Measurement of clay content in the foundry sand
Aim of the experiment:
To determine the clay content in the given sand sample.
Mechanism:
The instrument consists of stirrer, glass jar, siphon, timer unit, 53 micron sieve pan, wash bottle.
Sand Type: Green Sand & Raw fresh Sand
Procedure:
The clay content in the molding sand is determined as follows:
1.
2.
3.
4.
5.
6.
Dry thoroughly a small quantity of prepared molding sand.
Separate 50 gms. Of dry molding sand and transfer the same to a wash bottle.
Add in it 475 cc of distilled water and 25 cc of a 3% NaOH solution.
Using a rapid stirrer, agitate the whole mixture for about 10 minutes.
Fill the wash bottle with the water up to the mark indicated on the same.
After the sand etc. has settled for about 10 minutes, siphon out the water from the wash
bottle.
Clay is dissolved in water (due to stirring action) and gets removed along with the same.
7. To the sand thus left in the water bottle, add more water, stir the constituents again and
let the sand settle.
8. Repeat step 7 till the water over the settled sand is clean. This assures that the whole of
the clay has been removed from the sand.
9. Dry the settled down sand.
10. The clay content can be determined from the difference in the weights of the initial and
final (step 9) sand samples.
Precautions:
Clean the equipment after use. Protect the Parts from rusting; apply rust preventing oil when not
in use
Observation Table:
Sample Description
Wt. of Sand
(gm) (W1)
Wt. of dry Sand (gm) after
cleaning (W2)
% of Clay = {(W1W2) / W1}× 100
Raw Fresh Sand
Green Molding Sand ( sand+
Binder+ Bentonite + Coal
powder)
Fig: Clay content test: Electric stirrer
Result:
The average clay content in the given sand sample = ______________________