The Steel Industry in the World
The Beginning
Around 4,500 years ago, metallic iron used by man was found in natura in meteorites collected by nomad tribes in the deserts of Asia Minor. There are also indications of occurrence and use of this metallic material in regions such as, for example, Greenland. For its beauty, maleability and difficult obtention, it was considered a precious metal used mainly for decorative purposes.
Many support the theory that men discovered iron in the Neolithic Age, between 6,000 to 4,000 B.C. It appeared by chance, when pieces of iron ore were used to protect a fire and, after heated, they started to shine. This phenomenon, today, is easy to explain: the heat from the fire had melted and broken the pieces.
The use of iron in this period was always accidental and the example above is a good one of this situation. Although rare, there were times when the material was also found in its natural state – case of some meteorites (rocky bodies composed of various ores, including iron, which fly about in space and naturally fall on Earth). As it came from space, many peoples considered iron a gift from the gods.
Little by little, iron came to be used more often, since it was discovered how to extract it from its ore. Regular exploitation began around 1,500 B.C., probably in the Middle East, from where the metal would have been imported by Assyrians and Phoenicians. As from the first century of the Christian Era, iron earned its way all around the Mediterranean.
PróximoThe Iron Age
As per the system proposed in the 19th century by Scandinavian archaeologists, the Stone Age was followed by Metal Ages. Firstly, Bronze, and then Iron. The Bronze Age developed between 4,000 and 2,000 B.C. Since it was more resistant than copper, bronze allowed the manufacture of more rigid instruments and weapons.
The Iron Age is considered the last technological and cultural stage of Pre-History. In Europe and the Middle East, the Iron Age started around 1,200 B.C. In China, however, it had not started until 600 B.C.
The use of iron promoted great changes in the society. Agriculture developed more rapidly because of new tools manufactured. The confection of more modern weapons allowed territorial expansion of several peoples, what changed the face of Europe and part of the world.
From the observation of situations such as the fires in the Neolithic Age, men figured out how to extract iron from its ore. Iron ore started to be heated in primitive ovens (ball oven), below its melting point (temperature at which a material changes from solid state into liquid). By doing this, it was possible to retrieve some impurities off the ore, since they had a lower melting point than the sponge iron This sponge iron was then worked on an anvil to make weapons. To obtain 1 kg in iron bars, it was necessary to use 2 – 2.5 kg of pulverized ore and 4 kg of vegetable coal.
The first iron utensils were not very different from those made of copper and bronze. However, little by little, new techniques were discovered, making iron harder and corrosion-resistant. An example was the addition of limestone to the mix of iron ore and coal, allowing better absorption of the ore's impurities. New heating techniques were also developed, as well as the production of more modern materials to work on already cast iron.
Anterior PróximoEvolution
After years using the ball oven, the Catalonian forge (considered the embryo of today's blast furnaces) was developed. It appeared in Spain, soon after the fall of the Roman Empire, and was used throughout the entire Middle Age.
It was a fireplace made of stone and hand-operated bellows blowing air into the forge, increasing the temperature and the amount of iron produced. Later, mechanical bellows operated by servants or horses were developed. In the 12th century, water reels started to be used. With higher temperatures in the forges, it was possible to obtain liquid iron, rather than pasty.
The possibility of obtaining liquid iron brought about the technique of cast firearms, cannonballs and church bells. The use of iron was later extended to the nobility's homes of great gates and mantels with complex designs.
Around 1444, iron ore started to be melted in blast furnaces, a process still used until today. The temperatures reached by those furnaces were even higher, which allowed higher absorption of Carbon from vegetable coal. This made iron and steel alloys harder and more resistant. At that time, daily production of a furnace was around 1,500 kg.
The Industrial Revolution started in England, in the 1800's, would make iron production even more important for mankind. During this time, agricultural and rural communities started to lose importance to urban, mechanized societies.
The grate change, however, did not occur until 1856, when the process to produce steel was discovered. This is because steel is more resistant than cast iron and may be produced in large quantities, serving as raw material for various industries.
Anterior PróximoRecent facts
With the technological advance of furnaces and the increasing demand for steel and iron products, steel industries increased production. This generated problems, due to the fumes released into the atmosphere while burning vegetable coal. In the mid-1800's, the daily output of a blast furnace would reach three tonnes, increasing even more the consumption of vegetable coal.
Beginning in the XX century, the steel industries increased their investments in technology so as to reduce the impact of production in the environment, enforce the safety of the employees and the community, as well as produce more steel with less inputs and raw materials.
Steel is today the most recyclable and recycled product in the world. Cars, refrigerators, ovens, cans, bars and wire become scrap, fed to the mill’s furnaces, producing again steel with the same quality.
Furthermore, the steel companies take part in several international agreements to reserve the environment. In the 1990s, the United Nations Convention Panel for Climate Changes established a reduction in the emission of greenhouse effect gases, determining that the countries should submit projects regarding Clean Development Mechanisms (CDM). During the 2004 Stockholm Convention, the countries committed to developing a national control plan for Persistent Organic Polluting Agents (POPA). The steel industry is committed to both initiatives, as well as others in the same regard.
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