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 material, where they never think the importance of it in our life. Metals has helped developed this world trough out many times, different types of metals can be resulted to different usage of metals, there are soft metals and hard metals, each are uses differently. No matter what kind of usage these metals are to put trough, they all have an effect towards the human society.
Metal extraction is the separation process of metals in a pure or a rather pure state from the minerals, where they naturally take place. How we know a metal is a metal, it is based on its physical state, the physical state of metals are that it is mostly solids at room temperature, except mercury which is a liquid, they are ductile and malleable, which means they are able to be drawn into wires and metals can be hammered. Metals are also good conductor of heat and electricity because each metal atom loses its valance electrons and it is responsible for the conduction of electricity. Metals also have high melting and boiling points because the metal atoms are held together by a strong metallic bond they also have high density. The chemical properties are; metals are reducing agents because they lose electrons, they lose them to form positive ions known as cations. All metals reacts with oxygen to form basic oxides, metals also react with chlorine to form ionic chlorines. Metal extraction is done because it is use to get rid of unwanted rocks or other materials away from the obtained concentrated minerals, it is also used to obtain pure metals from the mineral by chemical reactions. A mineral is a solid element (pure) or compound (bonded with other elements) which occurs naturally in the Earth’s crust. A mineral which contains a high enough percentage of a metal for economic extraction is called a metal ore. Economic extraction means that the cost of getting this metal out of the ore is sufficiently less than the amount of money made by selling the metal. The most common metal ores are oxides and...
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