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The first two of these were eventually found in nature as well. Curium and americium were by-products of the Manhattan project, which produced the world's first atomic bomb in 1945. The bomb was based on the nuclear fission of uranium, a metal first thought to have been discovered nearly 150 years earlier.
The first elemental metal with a clearly identifiable discoverer is cobalt, discovered in 1735 by Georg Brandt, by which time the Scientific Revolution was in full swing. [6] (Even then, cobalt might have been prepared before the 13th century by alchemists roasting and reducing its ore, but,in any case, its distinct nature was not recognised.) [7]
Berzelius tried isolating the metal in 1825 by carefully washing the potassium analog of the base salt in cryolite in a crucible. Prior to the experiment, he had correctly identified the formula of this salt as K 3 AlF 6. He found no metal, but his experiment came very close to succeeding and was successfully reproduced many times later.
As the technology spread, iron came to replace bronze as the dominant metal used for tools and weapons across the Eastern Mediterranean (the Levant, Cyprus, Greece, Crete, Anatolia and Egypt). [14] Iron was originally smelted in bloomeries, furnaces where bellows were used to force air through a pile of iron ore and burning charcoal.
The addition of a second metal to copper increases its hardness, lowers the melting temperature, and improves the casting process by producing a more fluid melt that cools to a denser, less spongy metal. [6] This was an important innovation that allowed for the much more complex shapes cast in closed molds of the Bronze Age.
Copper was probably the first metal mined and crafted by humans. [6] It was originally obtained as a native metal and later from the smelting of ores. Earliest estimates of the discovery of copper suggest around 9000 BC in the Middle East. It was one of the most important materials to humans throughout the Chalcolithic and Bronze Ages.
In the later days of the Culture the metal was almost exclusively used for ceremonial items. [45] However, Lake Superior, as a unique source of copper for over 6,000 years has recently come into some criticism, particularly since other deposits have been found that other archiac cultures mined on a much smaller scale. [53] [54]
Metallurgy in China has a long history, with the earliest metal objects in China dating back to around 3,000 BCE. The majority of early metal items found in China come from the North-Western Region (mainly Gansu and Qinghai, 青海). China was the earliest civilization to use the blast furnace and produce cast iron. [1]