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Iron smelting is an industrial process used to extract usable iron from raw ore with the use of heat and chemical agents. After smelting, the iron can be further processed and alloyed with other materials to produce a wide range of metal products. These products can be used for everything from cooking utensils to the development of structural steel. Large-scale iron smelting occurs in facilities worldwide, particularly near large deposits of usable ores.
Smelting is often described simply as a melting process, but it is actually a chemical reaction. Iron ore doesn't feature chunks of iron embedded in rock, but a complex chemical compound. In smelting, a technician uses heat and a reducing agent to catalyze a chemical reaction that frees the iron so it can be extracted. Historically, humans used charcoal in their iron smelting, and coke is more common today.
A problem arises almost immediately with iron smelting. Most ores are not pure. Simply smelting with heat and a reducing agent would yield iron mixed with impurities that might compromise the quality of the metal. As a result, it is also necessary to add a flux. Limestone, for example, can be added to the mixture to separate impurities and leave behind clean, usable iron. Other fluxes are also available and a technician can select the most appropriate on the basis of what is known about the ore and how it performs during smelting.
Large furnaces are used for iron smelting, although early humans used pits and other environments in their metallurgy. Finished iron can be poured into molds to make blocks for easy handling, transportation, and shipment to other destinations. The metal can be melted to create alloys and annealed through heat treatments to create the desired level of strength and flexibility. Mistakes made during this process could result in brittle or discolored metals that might not function as well.
Engineers may supervise the iron smelting process on a factory floor to make sure the equipment is in working order and to confirm that people are operating it correctly. Personnel work in hot, sometimes crowded environments to control every stage of the process, pour off finished iron, and prepare for the next batch. The level of training necessary can depend on the facility and the position. Some train people with no prior experience to operate smelting equipment and monitor the metal while it is processed, while others look for employees with formal education or experience.