Page 4 - 3. Lesson Notes- Ch-3 Mettalurgy-2

Fig b.- Thermite process

ii. Reaction of MnO2 with Al powder-
When manganese dioxide is heated with aluminium powder, the following
reaction takes place –
3MnO2(s) + 4Al(s) → 3Mn(l) + 2Al2O3(s) + Heat

B. Extraction of Less reactive metals (Ores- Sulphides converted into
oxides by roasting ) –

➢ The less reactive metal Ores have a very low affinity for oxygen.
➢ Hence these oxides can be reduced by simple Heating. This is known as
Self reduction.

Example-

I. Cinnabar (HgS)-

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