Smelting Iron, Steel Manufacturing Technology

SMELTING IRON, STEEL

Tamilians had known the use of iron before the rest of the world knew it. They also had widespread access to the technology of extracting and tooling iron from the natural sources. They might have smelted iron and made weapons wherever necessary as a cottage industry. Such items are found here.

By the early 13th Century BC, iron smelting was practised on a large scale in India. It suggests that the technology might have originated as early as the 16th Century BC.

Evidence - Radio Carbon Dating

Some of the earliest iron objects found in India have been proved to be earlier than 1400 BC by Radio Carbon Dating Method.

Iron Furnaces at Kalayar Koil

In the following lyrics, Iyur Moolangkizhar says that king Venkai Marban, after being defeated by Ukrap Peruvazhuthi, regretted that saving his town was a rare act like saving water spilt on iron in a furnace. From this, it is understood that there is evidence of an iron smelting factory during the Sangam period.

Proof: Purnanooru 21

1. Flint Pipes

The existence of iron smelters is further confirmed by the presence of flint pipes in places where iron waste is found. These pipes might have been used for smelting iron or blowing air through the pipe to keep the fire continuously burning.

Evidence

A heap of iron waste was found at Raginipatti Kanmai in the Northern part near Paiyur on the highway from Sivagangai to Thondi. When the iron wastes were broken, the stones looked like iron.

2. Chennakuzhi Fire Furnace

Chennakuzhi is a combination of the word 'Chenth' which refers to the colour characteristic of red or red fire and the name 'na' which refers to the flame of fire and the name of the place 'Kuzhi'.

Chen + na + pit = 'red pit'

By being so called, we can realize that it functioned as an iron mill during the Sangam period. The information, data and names obtained confirm that an iron ore plant was operating at this place since the Sangam period.

Large circular pots of clay were probably used for smelting iron. Such pits are found wherever iron scraps are available. These were also called 'Chennakuzhigal' because they spewed fire.

Evidence

1. It is special to see a Chennakuzhi in Raginipatti Kanmai.

2. The pond in Porpanikottai is called 'Neeravi Kulam' and there is a Chennakuzhi near it.

3. Secondary Casting Plants

About 200 metres away from the Porpanai Fort, the secondary iron casing furnaces had been operating. The raw material redstones are not found here. So, this secondary raw materials required for the plant should have been obtained from the primary metal separation plant itself.

The carbon iron alloy thus obtained is melted in flint iron pots. Then it is poured into flint casting pipes to form the basic structure of long rod-like iron, as can be seen from the flint castings lying around here. And we can see that the lower part of these flint pipes is buried in the soil and molten metal is poured into it.

Evidence

From Thiruvarangam to Porpanaikottai, in some areas of the ridges with iron wastes, of earthern furnaces of iron smelting plants partially destroyed, flint iron pipes, iron containers used for waste disposal have been detected in many places.

4. Comparison of Sangam Smelting with Modern Smelting

The iron ore laterite rock is broken and pulverized and mixed with charcoal powder to subject it to the primary ore separation, where the ore is roasted at high temperatures and enriched with carbon particles. It can be seen in archaeological studies and historical records of metal smelting that it is used as a raw material for the next level of iron smelting. This can be compared with the modern metallurgical practice.

Herbal Use

Iron requires a lot of heat for melting it. They did not burn trees to that extent. Instead, they used herbs to smelt iron, which stands as the evidence of technology.

Location of Smelter

It is natural for factories to be located where raw materials are available. Accordingly, it has been found through the continuous field survey that ores have been mined near the iron ore smelter and the iron ore wastes are found scattered nearby.