By which method is the concentration of sulphide ore carried out?

Which method/process is used to obtain aluminium from pure alumina?

Which metal is purified by the method of liquation?

What change occurs in the concentrated ore during the roasting process?

During the extraction of metals,electrolytic refining is used to obtain pure metals.
$(a)$ Which material will be used as the anode and cathode for the refining of silver metal by this process?
$(b)$ Suggest a suitable electrolyte as well.
$(c)$ In this electrolytic cell,where do we get pure silver after passing an electric current?

Which of the following methods is $NOT$ a method for the refining of metals?