Extraction of Metals
Extraction of metals
The History of Metals.
Metals have been used by people for many thousands of years. Gold and silver, found as native metal, were used both as jewellery and as a status symbol - nothing new there. These metals were known in the Stone Age, but gold and silver are too soft to be used as tools.
The first really useful metal to be discovered was bronze. This began the Bronze Age. Bronze was used extensively for tools and weapons in Asia and Africa from 4,500 B.C. (6,500 years ago) and in Britain from 2,000 B.C. (4,000 years ago). News of the new material travelled slowly in those days and it took the Brits 2,500 years to get the message.
Bronze is not an element (like gold and silver) but an alloy (metal mixture) of copper and tin. Ores of both copper and tin are easily reduced by heating with carbon. This would have occurred accidentally as people lit wood fire in places where mixtures of tin ore and copper ore existed.
The hot burnt wood (carbon) would have reduced the ores to a mixture of copper and tin metal, which is bronze
After the Bronze Age came the Iron Age. People discovered that a high temperature coal fire could be used for the extraction of iron from iron ore. The extraction of iron today is done in a blast furnace. The Iron Age began in Asia and Africa in 1,100 B.C. and came to Britain in 500 B.C. In many ways, we are still in the Iron Age – take a look around. Metals above carbon in the reactivity series can only be extracted by electrolysis.
The discovery of electricity at the beginning of the nineteenth century allowed the extraction of the more reactive metals. Aluminium has been extracted on a large scale since about 1870, 3,000 years after the discovery of iron, and over 6.000 years after the discovery of bronze. For common metals in general, the more reactive the metal is, the harder it is to extract, and the later it was discovered.
Chemistry of extraction of metals.
For most people, metal is just a
The History of Metals.
Metals have been used by people for many thousands of years. Gold and silver, found as native metal, were used both as jewellery and as a status symbol - nothing new there. These metals were known in the Stone Age, but gold and silver are too soft to be used as tools.
The first really useful metal to be discovered was bronze. This began the Bronze Age. Bronze was used extensively for tools and weapons in Asia and Africa from 4,500 B.C. (6,500 years ago) and in Britain from 2,000 B.C. (4,000 years ago). News of the new material travelled slowly in those days and it took the Brits 2,500 years to get the message.
Bronze is not an element (like gold and silver) but an alloy (metal mixture) of copper and tin. Ores of both copper and tin are easily reduced by heating with carbon. This would have occurred accidentally as people lit wood fire in places where mixtures of tin ore and copper ore existed.
The hot burnt wood (carbon) would have reduced the ores to a mixture of copper and tin metal, which is bronze
After the Bronze Age came the Iron Age. People discovered that a high temperature coal fire could be used for the extraction of iron from iron ore. The extraction of iron today is done in a blast furnace. The Iron Age began in Asia and Africa in 1,100 B.C. and came to Britain in 500 B.C. In many ways, we are still in the Iron Age – take a look around. Metals above carbon in the reactivity series can only be extracted by electrolysis.
The discovery of electricity at the beginning of the nineteenth century allowed the extraction of the more reactive metals. Aluminium has been extracted on a large scale since about 1870, 3,000 years after the discovery of iron, and over 6.000 years after the discovery of bronze. For common metals in general, the more reactive the metal is, the harder it is to extract, and the later it was discovered.
Chemistry of extraction of metals.
For most people, metal is just a
Bibliography: http://www.docstoc.com/docs/23119872/Extraction-of-Metals http://www.greenerideal.com/business/0617-metal-extraction/ http://www.gcsescience.com/ex9.htm http://www.studymode.com/course-notes/Metal-Extraction-963844.html http://www.studymode.com/essays/Impact-Of-Metals-On-Society-1520044.html http://www.epa.gov/raf/publications/pdfs/HUMANHEALTHEFFECTS81904.PDF http://www.docbrown.info/page04/Mextracte.htm