Iron. The History of Iron Use

Iron is the earth's second most abundant metal resource, after aluminum. However, extracting iron from its ore requires only a tenth as much energy as does aluminum extraction. Iron's abundance, the relative ease of smelting it, and the varied services it can perform for us make it the most widely used metal. The annual consumption of iron and its alloys in the United States is about 500 kilograms per person. (By comparison, we consume only about 25 kilograms of aluminum).

Production of the large amounts of iron used by industrial society places heavy demands on energy and water resources, creates voluminous wastes, and can release undesired effluents. Disposal and recycling end-of-life products containing iron and steel are a significant part of the world's industrial economies today.

The History of Iron Use. People in southwest Asia began smelting iron nearly three thousand years ago. While bronze served as a symbol of wealth and power, iron's abundance and the relatively low cost of smelting it made the peoples' metal. Everyone who wanted iron tools and utensils and knew how to produce them could have them. As more people adopted iron, they initiated an Iron Age, which started around 2000 все in the Middle East, 1300 все in India, and 800 все in China.

While the Romans used massive amounts of iron, until about 1000 ce the most sophisticated iron technology flourished in Asia. The Chinese excelled in their use of the blast furnace to make iron to cast into utilitarian, ritual, and decorative objects. Indian artisans specialized in forging iron and making steel (an alloy of iron and carbon), which they exported to the West. This trade relationship was well established by 1000 ce. The African Iron Age, which began around 600 ce, lasted into the early twentieth century.

(There is no agreed-upon definition of the end of the Iron Age, but the following factors generally signal the end of what people mean by the Iron Age: (1) a significant increase in the scale of production; (2) adoption of water power for blowing furnaces; (3) adoption of the blast furnace in place of the bloomery forge.) In the New World the peoples of North and South America never used iron before European colonists arrived.

By the sixteenth century Europeans had mastered the techniques for manufacturing the iron and steel they needed to initiate Western industrialization. Subsequent European innovations—the coke-fired blast furnace for smelting iron and the Bessemer and Siemens (open-hearth) techniques for making cheap steel in large quantities—supplied the needs of the rapidly industrializing nations of the Atlantic community.

The iron and steel production per unit of gross national product increased around mid-nineteenth century as Western nations put infrastructure in place, and then began to decline in the last quarter of the twentieth century. It remains to be seen if the nations of the developing world can attain Western affluence with a smaller amount of iron per capita.