Poling

This method is applied to those metals which contain impurities as their own oxides. The crude metal is melted in a big container and is then stirred with green poles of wood. Gaseous hydrocarbons (CH₄, C₂H₆, C₂H₄, etc) are released from green poles which reduces the oxides of metals to the pure state by taking up oxygen. Copper is purified by Poling Process.