Question

Explain the following terms: Smelting.

Answer 1

To answer this question, you must recall the process of smelting. Smelting is a method of extractive metallurgy. It involves the process of heating an ore for the extraction of the base metal. It is a very significant process in metallurgy and is used commonly for the extraction of metals like iron.

Complete step by step solution
Smelting is the process of the extraction of a metal obtained either in the elemental form or in the form of a simple compound, from its ore by heating it to temperature higher than its melting point in the presence of oxidizing agents like air, or in the presence of reducing agents like coke. The process of smelting was first used for the extraction of copper metal in the ancient middle- east and then was used for obtaining tin, lead and silver. The high temperatures required for the process of smelting were achieved by the use of furnaces with forced- air drafts. It was necessary as the temperatures required for the smelting of iron are even higher.
In modern extraction processes, various primary steps are carried out for the purification of the ore as much as possible before it is subjected to smelting. In the smelting process of an oxide, namely iron oxide, the ore is heated to a high temperature. The oxygen combines with the carbon present in the fuel and escapes the mixture as carbon monoxide or carbon dioxide. Other impurities that are known as gangue are removed by the addition of a flux which combines with the former to form slag.

Note
Calcium oxide is used commonly as a flux while coke is used as a reducing agent and a fuel in the blast furnace in the smelting process of iron. During the process of smelting, the impurities that are known as gangue are removed by the addition of the flux which combines with the former to form slag.