Page 12 - Science India August 2022
P. 12

Swatantrata ka Amrut Mahotsava
by modern technology was also not sup- ported by the British government. Val- entin Ball observes that the total value of imported iron exclusive of that import- ed by the state between 1867 to 1879 amounted to Rs. 15,62,10,253; a large part of which might have been kept in India had the iron manufacture proved practical in India.
In fact, Ball was one geologist who favoured a new beginning of iron mak- ing in India, but in vain. If that were to happen, Indian mills would have been in direct competition with mills in Brit- ain, which was contrary to the industrial policy of the colonial power. Tatas could get permission to set up their iron and steel factory at Sakchi principally due to the demand created by World War I.
Finally in 1901, Indian Mines Act was enacted to provide regulation and inspection of mines. However, by that time, the indigenous unorganised min- ing had come to a complete halt.
Traditional Indian processes of produc- tion of wootz and metallic zinc provided sufficient inspiration to British scientists to replicate them through application of modern science.
In 1740, William Champion estab- lished zinc metal production at Bristol by a process based on downward distil- lation method of Zawar. Champion’s process used the same arrangement as that of Zawar, the only notable differ- ence being the use of glass retorts in- stead of the clay retorts of the Zawar process. SWK Morgan and PT Crad- dock observe, “Champion was notori- ously close with details of the Indian process at Zawar; possibly a third party described the general principles of the process to Champion.” Craddock con- jectures that the proximity of the first settlement of the East India Company at Surat to Zawar could be responsible for this technology transfer.
As regards the carbon steel, D Mushet in 1800 took out a patent for converting malleable iron into cast iron. John Percy, a noted metallurgist, com- mented on this patent as follows: “It is curious that Mushet’s process so far as
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Wootz, a steel invented in India, was an advanced material of the ancient world and in demand for making high quality Damascus swords
relates to the use of malleable iron in the production of cast steel, should in principle, and I may add even in practice too, be identical with that by which the Hindoos have from ancient times pre- pared their wootz. I cannot discover any essential difference between the two.”
Our current understanding of the Indian process of iron making is largely derived from the practices of tribes — Asur, Agaria, Brijias and Lohar. In- terestingly, iron produced by them is rust-less. In this process, iron ore and charcoal are heated (1000-1200oC) in a bloomery clay furnace, wherein iron oxide is reduced by carbon monoxide to form iron and iron silicate which forms a liquid slag. Iron lumps are then hot hammered to release the entrapped slag
Our current understanding of the Indian process of iron making is largely derived from the practices of tribes — Asur, Agaria, Brijias and Lohar. Iron produced by them is rust-less
out of iron mass, which finally yields wrought iron.
According to Valentin Ball, there were departures from the above dis- cussed procedure. In Kathiawar, the furnaces were reverberatory type, while in Waziristan, the flux of limestone was added to the charge. In Birbhum, iron was produced in liquid conditions in large furnaces and was run into pigs, which were subsequently converted in open hearths into malleable iron.
Valentin Ball sums up his findings in the following words: “If we take a sur- vey of the system of iron manufacture as practiced by natives of India, we meet here and there, traces of what may be the remnants of a higher system of working than those now existing.”
Unearthing this higher system is still a challenge on hand. Rust-less iron that Indians produced is still a subject of research. Readers may refer to an in- teresting article entitled, “Uncovering the superior corrosion resistance of iron made via ancient Indian iron making practice”, published by Australian re- searchers in Scientific Reports (2021).
*The writer is Professor, Depart- ment of Physics Indian Institute of Technology Bombay. He is also formerly Distinguished Scientist and Director, Chemistry Group, Bhabha Atomic Research Centre

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