When is Iron discovered?
There are some indications of the use of iron 4000 years before Christ, used by the Sumerians and also by the Egyptians.
Two or three thousand years before Christ more and more objects made of iron are emerging in places such as Mesopotamia, Anatolia or Egypt.
In spite of it, its use was fundamentally for ceremonies, because it was a very expensive metal, more even than gold. Certain sources suggest that it may be obtained as a byproduct when obtaining copper.
Between 1600 a. C. and 1200 a. C. its use in the Middle East is increasing. Although the predominant metal is bronze.
The discovery of iron between the XII century a. C. and X a. C. there is a rapid step in the Middle East from the bronze weapons to the iron ones due to the lack of tin.
This period is known as the Iron Age and was progressively implanted throughout the world. In Greece, it begins to be used about the year 1000 a. C. arrived in Western Europe in the seventh century BC. C.
The replacement of bronze by iron was gradual since it was difficult to locate the ore, then melt it at high temperatures, to finally forge it.
A review of the history
The Iron Age can be defined as the last stage of prehistory that began around 1200 BC when the very material that gave it its name managed to change everything.
Its antecedent lies in the Bronze Age (3500 to 1200 BC), a time when bronze was used to make all kinds of tools and in which the techniques to make them were polished.
Tools of the Iron Age
It should be noted that, with the discovery of iron, everything changes again. The weapons are harder, the stronger armor and the tools that were previously easily bent, now become the toughest ever manufactured.
Iron is everything for this period, a mineral that has since become something absolutely essential.
In Central Europe, it emerged in the ninth century BC. C. the culture of Hallstatt (replacing the culture of the fields of urns, which is called the first Iron Age, it coincides with the introduction of this metal.
Around 450 a. C. La Tène culture was developed, also called the second Iron Age. Iron is used in tools, weapons, and jewelry, although bronze objects are still found.
During this period of transition from bronze to iron, the carburization process is discovered, which consists of adding carbon to iron.
Until then iron was obtained by mixing iron with slag, with some carbon or carbides, then forged, removing the slag and oxidizing the carbon, thus creating the product with a shape. The iron thus obtained had a very low carbon content and could not easily be hardened by cooling it in water.
With the carbonization process, a much harder product could be achieved by heating the piece of wrought iron in a bed of charcoal, then submerging it in water or oil. The product obtained, which had a steel surface, was harder and less fragile than bronze, so it began to replace it.
In China, the first iron that was used came from meteorites. Wrought iron objects have been found in the northwest, from the 8th century BC. C. The procedure used was the same as that used in the Middle East and Europe.
In the last years of the Zhou Dynasty (550 BC) it is possible to obtain cast iron (product of the fusion of pig iron). The mineral found in China has a high phosphorus content, which melts at lower temperatures than in Europe.
The cast iron took longer to be manufactured in Europe because the necessary temperature was not achieved. The first samples of cast iron have been found in Sweden from 1150 to 1350.
In the Middle Ages, and until the end of the 19th century, almost all European countries used the steel method called farga Catalana, which consists of obtaining iron and low carbon steel using charcoal and iron ore.
This system was definitively implanted in the fifteenth century. It was possible to reach 1200 ° C. This procedure was maintained until the blast furnace stage.
In the beginning, charcoal is used in the process of obtaining iron as a source of heat and as a reducing agent. In England in the eighteenth century begins to be scarce so it becomes more expensive charcoal.
Coke, a fossil fuel, is being used as an alternative. It was first used by Abraham Darby, at the beginning of the 18th century, who built a blast furnace in Coalbrookdale.
The blast furnace evolved over the years. Henry Cort, in 1784, applied new techniques that improved production. In 1826 the German Friedrich Harkot built a blast furnace without smoke masonry.
From the end of the 18th century to the present day and the beginning of the 19th century, iron is widely used as a structural element (in bridges, buildings, …).
Examples of these are the great iron bridges that exist in the main cities of the world, the glass palace built for the universal exhibition in London, the Eiffel Tower in Paris, the Triana Bridge in Seville (Spain).
After the congresses of the last years, on the reserves of iron, the possible shortage of this metal has been approximated in 50 to 70 years, although the Sun sends us in the form of meteorites a quantity of this metal or that is suspected that the center of the earth is formed by a mixture of iron and nickel.
In any case, the current technique does not allow even the industrial use of these quantities very spread around the world.