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How Pavel Anosov quenched the steel and obtained gold from sand

Joint project of St.-Petersburg Mining museum and Forpost Nord-West.
Аносов
Фото © Павел Аносов на уральском заводе. Художник Г.М. Ламанов

The legendary metallurgist Pavel Anosov became world famous as the father of Russian damask steel, when he had managed to reproduce high-quality steel, whose recipe was lost in the Middle Ages. By his research, he also increased the extraction of gold from metal-containing sands by 28 times compared to conventional washing. Why was the scientist suspended from mining then, and the experiments were immediately blocked?

For the first time, the ubiquitous Aristotle mentioned damask steel. Thanks to a special production technology, such steel was distinguished by a peculiar internal structure, a pattern on the surface, but most importantly, its unique strength and elasticity. Therefore, since ancient times, it has been used to make swords, sabers and knives. The main suppliers for all of Europe were craftsmen from India, Persia and Syria. In front of shocked customers, they cut silk handkerchiefs with their blades on the fly, crushed stones and cut metal rods. The demand was incredible. In Russia, they also knew well about damask steel (bulat) and called it “red iron.”

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Фото © Персидский шамшир. Одна из последних булатных сабель.

Due to the high demand in the market, the eastern steelmakers kept the method of making damask steel in the strictest confidence. And this became the main reason for its oblivion... The conquests of Tamerlane in the 15th century, accompanied by the mass capture of artisans, primarily gunsmiths, led to a decline in the production of phenomenal steel, and then to the complete loss of the secret of its production. The remaining items were transferred to the private collections of wealthy people and museum depositories.

The St. Petersburg Mining Museum also had several blades; where they were shown to students of the Mining Cadet Corps as an example of skillful work with metal. In the spring of 1815, a 15-year-old boy entered the exhibition hall with a candle in his hands. Looking around, quietly so that no one could hear, he went to the display case where the damask blades lay. He looked at them for a long time and tried to figure out how the ancient masters managed to make them. And then, he sank into a chair and fell asleep.

горный университет
© Общественное достояние

The student woke up from the noise made by the ward. Near him, the class curator tried to fight the flames. A commotion arose, the fire was extinguished, but in the morning the cadet had to answer to the director of the school, Andrei Deryabin. The delinquent teenager got off with a strict suggestion. “We shall not punish the young man, for he is carried away by an issue, the resolution of which would do honor to the Empire.” The student’s name was Pavel Anosov.

The future inventor of domestic damask steel was born in 1796 in the Tver province into the family of a minor employee of the Berg collegium. Left an orphan in childhood, together with his brother and two sisters, the boy was sent to be raised by his grandfather, Lev Sabakin. The talented inventor and mechanic of the Kama factories (Izhevsk and Votkinsk) passed on to his grandson his love for technology, and a couple of years later, he sent him to the first educational institution in Russia that trained mining engineers.

After his successful graduation from Mining in 1817, Pavel Petrovich was assigned to the Zlatoust Treasury Plants. Here he served for almost 30 years, having passed all stages of the factory career: from an intern to the head of the mining district, which included metallurgical plants and Miass gold mines

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Фото © Общественное достояние, город Златоуст

After successfully graduating from the Mining School in 1817, Pavel Anosov was assigned to the Zlatoust state-owned plants. Here he served for almost 30 years, having passed all the stages of the factory career: from an intern to the head of a mining district, which included metallurgical plants and the Miass gold mines.

When the young man first arrived in Zlatoust, local enterprises produced not only cast iron and iron, but also various types of steel. However, despite the successes, metallurgical production required a radical reconstruction: the equipment was outdated and merely could not cope with the tasks set by the government. The results of the 1812 Patriotic War revealed the need to improve the properties of bladed weapons. The country needed high-quality steel. In addition, it was required for the production of machinery, which in a number of industries was replacing manual labor.

Having analyzed the available experience of various methods of smelting, Pavel Anosov was sure that it is cast steel that could fundamentally change the situation. He started his research and made many important discoveries in the course of his work.

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© Общественное достояние

To begin with, he organized the production of crucibles, or “melting pots,” as they were then called. It is an integral part of metallurgical equipment. Clay melting pots were used at Russian factories before, but the preparation of cast steel required pots of extremely high refractory properties. All local analogues cracked under the impact of high temperatures, so the only available way was bring them from Bavaria, where deposits of exclusively refractory clay were located. Anosov found out that the problem could be solved by adding graphite to the Chelyabinsk clay. As a result, the melting pots he made were not only super strong, but also cost more than 50 times cheaper than foreign ones.

This discovery allowed Pavel Anosov to carry out a number of experiments and develop a completely new method for producing cast steel, namely, gas carburizing. It consisted of re-melting waste, or, as the author himself put it: “in the fusion of unfit for operational use iron and steel cuts in clay pots, with the use of the elevated temperature of air ovens.”

In subsequent years, he developed the technology of melting, casting, forging, hardening, tempering of steel and its further processing. He applied the method of direct production of steel from ores in melting pots, proved the possibility of carburization of iron without the direct contact of coal to iron, and long before the open-hearth method discovered the technology of converting cast iron into steel with an ore additive, which is known today as the scrap process.

Experiments on the properties of steel helped the scientist to fulfill the most important for the state army orders, for example, to create lightweight and bulletproof kirasses. The Russian army’s heavy cavalry had previously been dressed in armor, but they only protected the soldiers from cold weapons. Specialists from the Sestroretsk plant, where the British were the main business conductors along with a French master named Sprenger, who was brought to Russia with the permission of His Imperial Majesty, had been tackling over the task set by the Tsar himself. But none of them had succeeded. Anosov took up the matter in 1838; he decided to make kirasses from cast steel. The result was not long in coming: the samples obtained were two times lighter than those in service with the army and withstood the blow of a rifle bullet from 60 steps.

Pavel Anosov continued to systematically study the structure of steel and the effect of various additives on it: chrome, silicon, gold, platinum, manganese, aluminum, titanium and other elements. He was the first who scientifically proved that physical and chemical and mechanical properties of the alloy can be significantly modified and improved by additives of some alloying elements. He was the first in the world to use a microscope to study the crystal structure as early as 1831, several decades earlier than scientists in other countries.

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Фото © Maximfil, Википедия, Булат

All these and many other experiments can be called the road to damask steel, which represents the top of Anosov’s scientific path. He was in active correspondence with metallurgists, who were trying to unravel the secret of oriental craftsmen, and with the owners of damask weapons. Chemical analysis of the samples presented to him showed that, apart from iron and carbon, there were no residual elements in steel. True, there was a lot of carbon, 1.5 - 2.0%. Realizing that no such composition could be obtained by casehardening of iron, the scientist came to the conclusion that the secret of producing damask steel was in the methods of preparing cast steel.

In the early 1840s, Pavel Ansov managed the impossible. As biographers put it, “by alloying soft iron with graphite and ore in melting pots, he recreated damask steel,” which was not inferior in its characteristics to the original sources from Ancient Persia or India. The Zlatoust plant started to produce it en masse. The weapon was exhibited in St. Petersburg, Moscow, London and everywhere it was marked with awards and raves.

Anosov compiled a detailed description of the entire production process. His assistant was the hereditary blacksmith Nikolai Shvetsov, who passed on the unique secret of the unique steel to his eldest son Pavel. In 1906, he sold the recipes for the manufacture to the management of the plant, but their further fate is unknown. The secret of creating damask steel was lost again. It became possible to reproduce the Zlatoust steel only in 1955…

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Фото © Форпост Северо-Запад / Горный музей

No less dramatic fate awaited another invention of the engineer. As the head of the Zlatoust mining district, he dealt with the mining of the “yellow metal.” Anosov improved the gold washing machine and installed it in the Miass fields. In addition, he found out that when washing gold-bearing sands, 130 times less gold was mined than it was actually contained in them. It was impossible to collect too small particles, as well as to extract from hard rocks. As a result, in 1837, Anosov tested and proposed a new method of obtaining gold from sands by melting in blast furnaces: during the smelting process, the noble metal was converted to cast iron, and after it could be extracted by dissolving in sulfuric acid. The method was first tested in small crucibles, and then in the shaft copper smelter and blast furnace. Experiments have shown a 28-fold increase in the enrichment efficiency!

The Committee of the Department of Mining and Salt Affairs has prepared a program of similar experiments at all mining plants in the Urals. The results impressed Emperor Nicholas I, and he instructed the scientist to continue research with the words: “I am interested to know more about this production.”

However, the success of the famous engineer did not please the new plant manager of the Ural Ridge Vladimir Glinka. Having considered Pavel Anosov an arrogant upstart, he was throwing spanners into the machinery. For example, he decided to personally participate in the revision of the experiments and made sure that Anosov was actually removed from the process. The experiments were carried out in a hurry: the sand composition was not checked beforehand, the fusion was carried out without control from metallurgists. As it could be expected, the initial results were not confirmed. Glinka attributed the research as “chimerical.” which he immediately reported on to the capital. Despite the ban, Anosov continued his tests. He was able to repeat them and in December 1837 sent five bags of gold extracted from the sand melting to the director of the Mint.

Nevertheless, the bureaucrat defeated the mining officer in this battle: the method was denied. The system of gold mining in Russia remained the same, but letters from Paris, Egypt and other parts of the world began to come to Zlatoust with proposals to continue research abroad. The mining engineer remained in his homeland and died in 1851 in Omsk. His method began to be used only almost a hundred years later, in particular, when refining non-ferrous metals.