We are all made of stardust, say some imaginative, poetic writings. Literature is not always a fantasy; this could be true because all iron on Earth came from the stars or meteorites. Today, iron is not only a major element found in the human body, but it is also a metal that surrounds us in the form of almost everything. From the skeletons of our houses to the cutlery we use, everything is made of iron (in the form of steel).
What is Iron?
Iron is a transition metal found in the group 8b of the periodic table along with other transition metals. Unlike transition metals, iron is found abundantly in the Earth’s crust and core, making up 5 percent of the former and 35 percent of the core. Iron found abundant use by mankind in making tools used for daily life chores, large iron structures like gates and forts, and even exotic ornaments. But iron is very reactive as a crude metal, and humans had to design various ways to make it useful without letting it corrode.
The journey of iron is an interesting one. Let us have a look.
The Earliest Use of Iron
Iron has been reported to be used since ancient times, as old as 5000 BC. There is evidence of iron artifacts from Mesopotamia that date back to 5000 BC. Iron crafts have also been found from ancient Egypt, dating to around 3500 BC. There is evidence that iron is of meteorite origin, as these artifacts contain a fair amount of iron along with nickel. Such large quantities of nickel were found only in meteorite iron.
In those days, people did not realize that iron was abundant on Earth. It was considered much more valuable than gold and also very sacred because the people believed that it was a gift from the heavens.
Use of metals was not a foreign concept, though, but before iron could come in use, the people used bronze. This period was called the Bronze Age. It was not until the mid of Bronze Age that bronze gave way to iron for use. During that period, people learned smelting it. Smelting is a process whereby a metal is extracted from its ore. Magnetite and hematite were the main ores of iron. Smelted iron was recovered and identified as belonging to the period around 3000 to 2700 BC. It was first used by the Syrians and Egyptians.
Artifacts made of smelted iron have been identified dating back to as earlier as 1800 BC from India. A mention of black metal or Syama Ayas is found in the Hindu religious scripts that originated during that period.
The Iron Age
With the end of the Bronze Age, iron became popular, and through trade routes, it spread across the globe. Historians and scientists say that the Iron Age began around 1200 BC. This period saw the extensive use of iron for all purposes, and developments took place in finding out better methods to extract, strengthen, and use iron. Iron was heavily used during this time in Greece, Rome, and in the Far East in Persia and China.
The production of cast iron had begun in China in the 5th century BC. The production of steel required the proper mixing of carbon with iron, and it was a process that required high temperatures and furnaces, and only a few civilizations had mastered it.
Proto-Hittite layers at Kaman-Kalehöyük in Turkey have been known to have produced steel, dating back to 2200–2000 BC. But it is evident that the Persian Empire that was growing fast during the Iron Age were the first ones to build armors and war equipment entirely out of steel. Europeans had learned the building of fortresses that used iron for heavy gates and hence provided them protection. Around 1100 BC, the Europeans were quickly replacing bronze with iron for the production of utensils, tools, and weapons.
The Beginning of the Production of Steel
Iron cannot be used in its raw form as it is a highly reactive element. Therefore, there had to be a way to use iron by making it corrosion-resistant. The answer was steel! The production of steel from iron was discovered and practiced by different civilizations along different periods.
Around the middle of the Bronze age, about 1800 BC, the Chalybes were the people who were looking for something stronger than bronze to produce unrivaled weapons. They used hearths to heat iron ores and hammered them into desired shapes. Soon the Chalybes joined the Hittites, and together they built an army whose weaponry became unmatchable. This iron was called wrought iron and was the first step towards the production of steel.
The Iron Age evolved rapidly in China, and in the 5th century BC, the Chinese were already having blast furnaces and producing cast iron. They burnt together iron and wood to achieve the mixing of carbon with iron. The cast iron produced this way contained 2 to 4 percent of carbon and was not yet perfect steel, as it was too brittle.
The real steel first came into being in the Indian subcontinent, where the quest for the perfect steel led the Indians of 400 BC to devise a unique method for the production of cast iron, the first kind of steel. The steel here was produced by the crucible method. Wrought Iron, coal, and glass were mixed in a crucible and heated inside furnaces until such temperatures were achieved that were necessary for melting iron. The iron melted and absorbed carbon, which on cooling, produced perfect steel bars. Sri Lankans had learned to put to use the monsoon winds to create pressure differences among the furnaces and were known to produce high-quality steel as early as 300 BC.
The Indian steel found its way almost around the entire globe. The Syrians hammered this steel to produce swords about which they boasted that these could even cut feathers in midair.
Blast Furnace
The production of wrought and cast iron required blast furnaces that were developed over time. The first real blast furnaces are attributed to China. In the 1st century AD, China was the first region to have produced the blast furnace. In contrast, the blast furnace did not reach Europe and the West until the medieval ages.
Moving Towards Better Steel
The hunger for high-quality steel and iron took over Europe entirely in the 12th and 13th centuries AD. Firearms were being produced, and good quality iron was required to cast into the molds and make better weapons. In Germany, 10 feet tall furnaces were developed, and iron was seen to be absorbing more coal than ever. This produced better cast iron, which could be poured directly into molds. It was nicknamed pig Iron.
As the requirement for iron soared, the problems for Europe rose as well. Europe soon realized that to produce such iron, they were consuming trees like never before. The solution to the problem was being sought and was given by Abraham Darby, but not until 1700. He realized that instead of charcoal, roasted coal or coke should be added to the iron. This produced better quality iron, and Britain began pouring weapons into the world.
Iron as a Monument
The production of good quality cast iron led the world to the Industrial revolution. The availability of cheap and better-quality iron had done its job. Towards the end of the 18th century, cast iron had taken over the use of wrought iron. The First Iron Bridge was built in 1778, over the River Severn in Shropshire, England. The bridge still stands as a commemoration of the role iron played in the Industrial revolution.
The Best Steel!
The abundance of iron ores on Earth and the hunger for steel led humanity to discover better methods of producing steel, and that too more abundantly. To the world’s surprise, the best steel would be produced by a doctor! A doctor and surgeon dedicated his spare time to find out methods of producing steel that none had ever seen before. He tested various methods.
Eventually, he came up with one quite similar to the ancient Indian techniques. The doctor, however, used the technique of Darby – he roasted the coal and heated the iron and carbon over a bed of coals. It was a huge success. Sheffield, in England, beamed with pride and became the center for steel production. Soon entire England adopted the method, and English Iron and steel furnaces burned bright.
British vs. American Steel
It seemed the British had totally taken over all iron and steel production, and they had done so very enthusiastically. They worked tirelessly to produce innovative and better methods to produce iron from its ores and use it to produce steel. The year 1856 saw the production of the Bessemer Converter. Through the use of air to burn the coal, people were able to produce pure iron. This means that iron was now at the human disposal, and they could use it as they wished. The problem, however, remained, which was of removing phosphorous. That problem was solved by another British steel enthusiast, who suggested the use of lime. Britain began producing larger than ever quantities of iron.
Britain ruled the world at the time, and no wonder it did! With the fast-paced industrial revolution and newer and more reliable methods to produce better iron, Britain was the king.
Towards the end of the 9th century, a business enthusiast, Andrew Carnegie, introduced the production of Steel through Bessemer’s procedure to America. He began producing more than half of American steel. Andrew Carnegie had given America the gift of steel, and owing to his hard work, in 1900, America became the largest producer of steel. The steel produced in America soon found its way to forming the skeletons of the skyscrapers, more specifically the Empire State Building. Later, which became the landmark of the USA in the early and late 20th century.
The furnaces kept burning during the war and produced metal to fight, travel, and build bridges. Humans, however, never stopped looking for better ways to produce the iron. Stainless steel was a game-changing invention that came in the late 20th century. Again, it was Britain that was crowned with the production of ‘rustless’ steel or stainless steel that meant iron could now be used fearlessly to produce anything. There was no fear of it being corroded.
Other than the USA and Britain, Japan and China jumped into the steelmaking business as well, leaving behind the two-parent countries of steel. The world has iron and steel furnaces all around now. With almost everything being produced from metal, it is nearly incumbent upon every country to produce its share. The furnaces burn throughout day and night.
Conclusion
Iron has been used over thousands of years, and yet it continues to be abundant in the Earth’s crust and core. Also, humans have learned over these years to put the iron to the best use. It is only a matter of time before newer and cheaper methods of metal extraction will be devised, and the production of alloys will take over – leading to perhaps another revolution.