sir,kindly explain what is an alumino thermic process?
Chromic oxide is mixed with powdered aluminum the ratio 3:1 and is placed in a large fire clay crucible. A mixture of barium peroxide (BaO2) and magnesium (Mg) powder is placed over this. The crucible is surrounded by sand, which prevents loss of heat by radiation. The mixture is ignited by a piece of magnesium ribbon. During this process a large amount of heat is liberated, in which chromic oxide is reduced to chromium. The molten chromium is collected in the crucible and aluminium oxide is removed as slag.
The overall reaction is:
- Cr2O3 + 2Al â Al2O3 + 468.6 KJ