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What did Africa invent? Steel in the 5th Century BCE

Earliest Use of Steel in Africa

In the past, many historians and scientists have looked to Europe for the advent of Iron smelting and the use of steel in many different structures. However, evidence points to the fact that the Haya, who lived near Tanzania, had their own method of smelting iron, to create high grade steel, which was different from the Western process, and created much earlier as well.

History of the Haya Tribe

The Haya are an African tribe that focused on agriculture. They were based along the Western shore of Lake Victoria, which can be found in Modern Day Tanzania. The Haya tribe live in village and survive on cattle rearing and subsistence agriculture. Currently, they do grow some cash crops in the shape of  Coffee and tea. The Haya tribe have oral traditions that tell us about iron production and smelting in the Kyamutwara Kingdom. This dates back to around 2400 years ago.

Smelting Method

It has recently been observed by Historians that the smelting method used by the Haya tribe was different from the methods used by Western Nations.

steel - pic1
A model of the Haya smelting method

A recent study of smelting methods was made to discover how temperatures in excess of 1300 C were achieved in ancient times. Tuyere fragments (Pipes) were found near the smelting sites. In addition, further testing revealed that the tuyere fragments had come from inside the furnace. This helped the researchers conclude that preheating done via this way could be used for smelting, as the Haya traditions had said they did. Carbon testing was also used to verify the dates and conclude that smelting was done at these sites around 2000 years ago, and with a different methodology.

The Haya had placed their tuyeres or pipes inside their furnaces. This would create a blast of hot air which would help to heat the furnace. Preheating a furnace in this way would allow the Haya tribe to reach temperatures in excess of 1200 C, using a method not used in the Western World till around the 19th century.

The Haya placed tuyeres or pipes inside their furnaces, as the data showed, but this is where the similarity with current methods differs. The furnace is what is called a shaft-bowl type, which means it has a bowl shape. It also is of a forced-air draught type. A forced air draught means that air is forced into the furnace, while the bowl shaped shaft is around 60 centimeters deep and the surface is lined with mud. A cone-shaped shaft 140 centimeters high is made with old, refractory slag and mud, which usually comes from a termite mound. This is built over the bowl.

To run the furnace, the Haya burnt Swamp grass until the bowl was filled with the charred swamp reeds.  These reeds provided the carbon which is smelted with the iron, to form steel. It was truly an inventive way of smelting. While the steel produced in this way was not pure steel as we know it today, it was advanced for its time, and a very great innovation. The air was forced into this furnace by the use Eight drum bellows, which were covered with goatskins. In this way, the combustion zone just beyond the tuyeres develops a very high temperature.

At this point, the byproducts of the combustion of the swamp grass divide, part of them pass up through the furnace shaft and part of them flow back along the tuyere. This process further heats the tuyere and the blast air passing through it.

Eventually, the external tuyere surfaces are wet with slag and dissolve in it at about 1250 to 1300C. This dissolved slags prove that the external temperature was in excess of 1200 C. In this way, the Haya could smelt iron in excess of temperatures that had been taught possible by medieval methods.

Further Research and Reconstruction

A recent study managed to reconstruct some of the smelting sites of the Haya Tribe so that experiments could be carried out. The air temperatures inside the tuyere were measured by passing a ceramic-insulated thermocouple down the tuyere. We can find the results in the graph below

The graph shows that temperature of the furnace reached in excess of 1500 C at the start of the smelt, and even during the end of the smelting process could be found near 1500 C. The temperature reduced as you got further away from the tuyere, pointing to temperature being conducted by radiation in the higher temperature zones.

For comparison, an 8th century furnace tested in Czechoslovakia reached temperatures of just 1450 C, despite being constructed a whole 8 centuries after the ones at Haya. This showed how advanced the technology was for the time. This would mean the iron would be formed much more efficiently from slag, and that any smelting of iron with carbon would produce much higher grade steel at Haya than at European furnaces.

There’s another significant difference in the process at Haya and the ones used in Western Nations. It covers a concept in steel making known as bloomery, which was used in earlier furnaces. A bloomery produces a type of iron known as sponge iron, which needs to be further refined into pure iron. The process at Haya was much more efficient precisely because it avoided this step. For context of how huge this is, the elimination of the Bloomery process in Spain did not happen till the 19th century.

In the Haya smelting process which was investigated in the furnace of West Lake, iron is precipitated as large crystals growing in a fayalite-wiistite slag. This is similar to the process in a bloomery, but with a critical difference. The iron is roasted, and then reoxidised. The contact of this iron with the swamp reed then helps avoided the production of sponge iron, and instead produced pure iron. This made the process at Haya very efficient and very different from the European one.

Analysis from six reconstructed smelts in West Lake during 1976 showed that they have a carbon content ranging from pure iron to ones with some impurities.

African Smelting in General

Other than the Haya tribes, similar furnaces were found in Uganda. Further studies have shown that this is not just limited to one or two tribes in Africa, but similar furnaces were also found in Modern Day Rwanda, pointing to a degree of complexity that archaeologists had not previously expected.

Uses of Iron in the Modern World

Today 1.7 million tonnes of steel is produced each year worldwide. The greatest structures in the modern world today are made of iron. A lot of magnetic instruments and compasses rely on either iron or steel. Most electromagnets also rely on these two metals. Furthermore, there are very few gadgets that we use in our everyday life that do not rely in some shape or form on either iron or metal.

steel in africa - Royal_Oak_Offshore_watch_by_Audemars_Piguet
Royal Oak luxury watch

In ancient times, weapons were also made chiefly from iron, such as swords. The existence of high grade steel in Africa no doubt led to the great empires in Africa that were present in times past.

Closing remarks

The biggest conclusion that can be drawn from the West Lake discoveries is that a superior smelting process existed in Africa nearly 2,000 years ago. This shows that a technologically superior process existed in Africa rather than in Europe, and it is a conclusion that has huge implications for the history of Africa as we know it.

It is no longer good enough to teach inaccuracies to future generations and put any random version of the “truth” on Wikipedia. Today, you will find Benjamin Huntsman credited with being the English inventor of steel. History is global, not a silo, Western, Eastern, black or white. Time to credit each culture with their contributions to humanity, not white-wash the past.

Source

Peter Schmidt and Donald H Avery, Science, New Series, Vol. 201, No. 4361 (Sep. 22, 1978), pp. 1085-1089. Published by the American Association for the Advancement of Science. Retrieved 05-01-2015.

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