During the process of electrolytic refining of copper Ag and Au are obtained as anode mud.

Na₃AlF₆(cryolite)is used to decrease the melting point of Al₂O₃ prior to electrolysis to get pure aluminium.

Froth floatation process is used for sulphide ores in which ore particles are accumulated in froth and the impurities remain in solution.

Due to high affinity for oxygen aluminium reduces several metallic oxides like Fe₂O₃, Cr₂O₃, Mn₂O₃ etc.
Cr₂O₃ + 2Al + Al₂O₃ + 2Cr + Heat
This process is known as thermite process.

Flux is used during metallurgy to remove silica and undesirable metal oxides.

Fluorine is the most electronegative element. Hence its electron affinity is highest. By gaining one electron it completes its octet. Whereas oxygen needs electrons,O^- is already a negatively charged species hence have some repulsion for the incoming electron. Na⁺, will again loose its octet by gaining electron.

PbS reduces PbO to Pb and SO₂ is liberated. This is called as self-reduction.

Calcination is heating ore in absence of air to remove moisture and volatile impurities.Carbonate ores decomposed to corresponding oxides as a result of calcination.