What is the poling process?

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Hint: Poling is the metallurgical process of purifying the metals like copper and tin (oxidized impurities). Poling is a method used to purify metals that have oxidized impurities. It is typically used to purify metals like copper or tin that are in the impure form of a copper oxide or tin oxide.

Complete answer: Metals that are having oxidized impurities can be purified and the metal can be extracted by the process called poling. A log of wood which must still be green is used to stir the liquid metal. The hydrocarbons in the green wood can reduce the metal & the oxygen released as \[C{{O}_{2}}\]​ gas. The reaction between metal oxide and carbon is given below:
\[MO+C\to M+C{{O}_{2}}\]
This is the old method of extraction of copper metal from its oxide. In which oxidized impurities that support oxide is present. Copper can be purified to extract copper metal.
The impure metal is placed in the furnace in which iron and sulfur are removed gently by blowing the air through the molten metal for the formation of iron oxide and Sulphur dioxide and these will be skimming off and in the foam of exit gas
Then the molten impure metal is stirred with green poles of wood. The green poles of wood release the hydrogen gases which reduce the oxide impurities.

Note: Natural gas or diesel, ammonia etc are also used as reducing agents in place of green wood in the modern days for the process of poling. It is conveniently used for the metals like copper and tin because carbon has more affinity for oxygen than these metals and thus carbon is able to reduce them.