it was not until nearly 3000 years ago that higher temperatures could be reach and less readily reduced elements ,such as iron ,could be extracted ,leading to the iron Age. These elements were produced by heating the ore to its molten state with a reducing agent such as carbon . this process is known as smelting .Carbon remained the dominant reducing agent such as until the end of the nineteenth century,and metals that needed higher temperatures for their production remained unavailable even though their ores were reasonably abundant.the availability of electric power expanded the scope of carbon reduction because electric furnaces can reach much higher temperatures than carbon-combustion furnaces,such as the blast furnace.Thus,magnesium is a metal of the twentieth century because one of its modes of recovery ,the Pidgeon process, involves the very high temperature,electrothermal reduction of the oxide by carbonNote that the carbon is oxidized only to carbon monoxide,the product favoured thermo-dynamically
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