: 220
The extraction method directly correlates with a metal's position in the reactivity series — this is the single most important organising principle in metallurgy.
Very reactive metals (Na, K, Ca, Mg, Al): Extracted by electrolysis of fused salts/oxides. Their oxide-formation lines lie at the very bottom of the Ellingham diagram. No chemical reducing agent is powerful enough.
Moderately reactive metals (Zn, Fe, Ni, Sn, Pb): Extracted by carbon reduction (smelting). The carbon line crosses their oxide lines at accessible temperatures.
Less reactive metals (Cu, Pb from sulphides): Self-reduction possible. The sulphide and oxide of the same metal react to give free metal.
Least reactive metals (Ag, Au): Found native or extracted by cyanide leaching followed by displacement with zinc.
Key metal-ore-method associations for JEE: Fe/Fe2O3/blast furnace with CO; Cu/CuFeS2/froth flotation + self-reduction; Al/Al2O3.2H2O/Bayer's + Hall-Heroult; Zn/ZnS/froth flotation + roasting + carbon reduction; Au/native/cyanide process + Zn displacement; Ni/NiS/Mond process refining.