Question

Write the name of different stages of obtaining pure metal from its ore. Explain refining of copper by electrolysis with diagram?

Answer 1

The process of obtaining pure metal from the ore is divided into five steps:
$\bullet$ Crushing and grinding of ore
$\bullet$ Concentration of ore
$\bullet$ Roasting, calcination and smelting
$\bullet$ Reduction
$\bullet$ Refining of metals
For refining impure copper by electrolysis:
$\bullet$ A thick block of impure copper is used as the anode.
$\bullet$ A thin strip of pure copper is used as the cathode.
$\bullet$ A water-soluble salt is taken as an electrolyte.
$\bullet$ On passing current through the electrolyte, the impure copper from the anode dissolves into the electrolyte.
$\bullet$ An equivalent amount of pure copper from the electrolyte is deposited at the cathode.
$\bullet$ The soluble impurities go into the solution, whereas the insoluble impurities settle at the bottom of the anode and are known as anode mud.
$Anode:C{u}_{\left(s\right)\left(Impure\right)}\to C{u}_{\left(aq\right)}^{2+}+2e^{-}$ (oxidation)
$Cathode:C{u}_{\left(aq\right)}^{2+}+2e^{-}\to C{u}_{\left(s\right)}$ (reduction)
Net reaction: $C{u}_{\left(s\right)\left(Impure\right)}\to C{u}_{\left(s\right)\left(Pure\right)}$