Metals Through Ages Fathi Habashi
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Laval University From the SelectedWorks of Fathi Habashi 2015 Metals through ages Fathi Habashi Available at: https://works.bepress.com/fathi_habashi/163/ Metals Through the Ages. Their Discovery and Isolation Fathi Habashi Laval University, Quebec City Canada Metall volume 69 2015 METALL-RUBMETALL HISTORIKRISCH produced beautiful artefacts. As early as Metals Through the Ages. the Fifth Dynasty (2690-2420 BC) the ancient Egyptians documented primitive metallurgical operations on wall paintings Their Discovery and Isolation which show blow-pipes in use with small furnaces and later they depict the use of bellows so that a high temperature can be Habashi, F. (1) Part 1 reached when air is blown in the fire by these means (Figure 1). They were able to Seven metals were known to the ancient people: gold, silver, copper, iron, mercury, hammer gold so that foils can be produced lead, and tin. In the Middle Ages the metalloids arsenic, antimony, and bismuth and used for gilding wood and stones. were added. Platinum was later brought from South America then zinc and boron became known from the East. It was only in the eighteenth century that mineralo- Silver and lead gists, travellers, and analysts supplied mineral specimens from different localities to laboratories where they were analyzed and this resulted in the discovery of ura- Silver occurs as native metal or an alloy with nium, zirconium, yttrium, beryllium, and chromium. In the nineteenth century the gold called electrum. The mines of Laurion bulk of metals became known mainly due to Swedish chemists. In the twentieth century the very rare remaining metals: rhenium and hafnium were discovered and isolated. In the meantime metals that do not occur in nature or occur only in infini- tesimal quantities: protactinium, technetium, francium, promethium, and the trans- uranium metals became known and were isolated. Reasons behind the discovery are analyzed. eople had inhabited the Earth for temperature can be attained by burning hundreds of thousands of years carbonaceous material. before they began to use metals. W Some of these metals have low melting This was the Stone Age in which points, for example, lead and tin, while Pthe only tools available were pieces of wood, mercury is already liquid at room tem- bone, flint, or sea shells. The ancient people perature, thus they are easy to recover. used only those metals that were available Impurities in a metal lower the melting without mining or chemical treatment, for point considerably; for example, iron Fig. 2: Ancient Greek coin example, pieces of native gold, silver, and containing 4% carbon already melts copper, and rare pieces of meteoric iron. at 1100 °C while the pure metal melts near Athens in ancient Greece supplied These were too small in quantity to be of at 1540 °C. Metals used by the ancient most of the silver which was mainly used to any consequence. people were seldom pure. Brass, an alloy mint coins (Figure 2). Lead ores also con- of copper with zinc, was prepared by tain silver and they were sometimes treated The seven metals of antiquity smelting a copper ore and another ore for silver. Lead was widely used in Roman known as calamine. times mainly in making pipes (Figure 3). The ancient people knew only seven met- als: gold, silver, copper, iron, mercury, lead, Gold and tin. There are reasons for the early availability of these metals: As civilization progressed, gold became W Some of these metals occur in the native an important metal in Egypt. The phar- state, for example gold and silver. aohs sent expeditions of ten of thousands W Oxides of copper, iron, tin, and lead of slaves and soldiers to mine gold in the are readily reduced below 800 °C. Such Eastern Desert. They cast the metal and Fig. 3: Typical Roman street with lead pipe Copper and tin Metallic copper was produced by the reduction of its oxide ores in primitive furnaces. Sinai in Egypt and Cyprus were Fig. 1: Ancient Egyptian wall paintings showing furnaces, manually operated bellows, the main producers. This is believed to melting, and casting of gold be the first metal produced from oxides 292 7-8/20156/2011 | 65.69. Jahrgang | METALL METALLMETALL-RUB HISTORISCHRIK gold; neither of the acids alone has any dis- solving action on gold. Nothing worthwhile in the field of metallurgy took place during the dark ages of magic, superstition, and alchemy except that many acids and salts were prepared, described, and used for a variety of purposes. Fig. 4: An ancient copper ingot [British Museum] by reduction around 4000 BC. An ancient copper ingot is shown in Figure 4. This was, however, slowly superseded by bronze – a copper alloy containing about Fig. 6: Iron Pillar of Delhi [fourth century 10% tin, easy to melt and to cast. Bronze AD] was either produced by mixing tin pro- duced from its oxide by reduction, with (Figure 7). Gold leaf adheres firmly on the metallic copper, or by reducing a mixture shiny amalgamated copper surface. of copper ore with a tin ore; this period of Fig. 8: An alchemist at work civilization became known as the Bronze Age. A Roman tin ingot is shown in Fig- The flow of knowledge from the East ure 5. to the West The art of making Toledo swords, famous for 200 years thrived under the Arabs in the eighth century A D. There was cultur- al contact between the Arabs in Damas- cus and the Indians, who excelled in iron making. It was only with the translation of Fig. 5: Roman tin ingot Arabic texts into Latin, and henceforth the [Royal Museum in Truro, Cornwall] flow of alchemical knowledge to Europe in the tenth century, and the appearance of Iron the Renaissance in Italy few centuries later, Fig. 7: A once gilded bronze statue of Mar- that the art of metal extraction started to Iron became known much later than cop- cus Aurelius in Rome take shape. per although iron ores are more abundant than copper ores, having colorful miner- The age of alchemy New metal discoveries als, and almost as easy to smelt. This may be due to the fact that copper can be shaped When an alchemist (Figure 8) dipped a piece In the thirteenth and fourteenth centuries by cold-hammering, whereas iron must be of iron into a solution of copper vitriol, i.e., three new metalloids: arsenic, antimony, hammered hot. The Iron Age began around copper sulfate, the iron was immediately and bismuth became known in Europe in 2000 BC and most probably the Hittites in covered by a layer of metallic copper. This the elemental state and were described by Asia Minor were skilled in this technology. apparent transmutation of iron into cop- Not many iron objects resisted corrosion per led the alchemists to be occupied with through time except perhaps the Iron Pil- the transmutation of base metals into gold. lar of Delhi which was made in the fourth Gold, the most noble of all metals was insol- century AD (Figure 6). uble in all acids or alkalies known at that time. The Arab alchemists of the eighth and Mercury ninth centuries, e.g., the Jabir Ibn Hayyan (720-813 AD) thought they could change Mercury was recovered by heating cinna- iron into gold, a process which became bar ore which occurred in abundance in known as the transmutation of metals. He Spain and north of Italy. It was used as a discovered aqua regia, i.e., royal water is a Fig. 9 and 10: Albertus Magnus (1193-1280) (left) and Georgius Agricola (1494- 1555) sticking medium to gild copper statues mixture of HCI and HNO3 that dissolves METALL | 65.69. Jahrgang | 6/20117-8/2015 293 METALL-RUBMETALL HISTORIKRISCH the German monk Albertus Magnus (1193- 1280) (Figure 9) and others. Mining and metallurgical literature In the sixteenth century two important books on metallurgy appeared. The first “De La Pirotechnia” appeared in 1540; its author Vannoccio Biringuccio (1480-1538) was working in the Armoury of Siena in Italy, and had traveled widely through Ger- many and Italy. The book, written in Italian, was concerned with ores, assaying, smelt- ing, separating gold from silver, making of alloys, melting, casting, and fireworks. The Fig. 11: Antonio de Ulloa (1716-1795) second book “De Re Metallica” appeared in 1556; a year after the death of its author, attention to this metal when he visited Georgius Agricola (1494- 1555) (Figure 10) this region. The Spaniards unable to melt a medical doctor from Saxony who traveled these particles, they called them platina a widely in the mining districts in this area. diminutive of silver. It took nearly a cen- The title means “Of things Metallic”; it was tury to identify and isolate the components the reference book on mining and metal- of platina: lurgy for at least two centuries. W 1750: Brownrigg and Watson, platinum Fig. 13: Chinese method for producing zinc Fire Assaying W 1803: Tennant, osmium W 1803: Tennant and Des Costils. ble (Figure 12). By 1374, the Hindus had Control of the purity of gold and silver, iridium recognized that zinc was a new metal, and and the prevention of counterfeiting of W 1803: Wollaston, rhodium and a limited amount of commercial zinc pro- coins was always of primary importance palladium duction was underway. to the administrators of the early com- W 1844 : Klaus, ruthenium From India, zinc manufacture moved to munities. It is not surprising, therefore, China where it developed as an industry to that methods for analyzing gold and silver Metals from the east supply the needs of brass manufacture (Fig- were developed. The earliest known pro- ure 13).