Production
The production of the metals itself is difficult due to their reactivity. The formation of oxides, nitrides and carbides must be avoided to yield workable metals, this is normally achieved by the Kroll process. The oxides (MO2) are reacted with coal and chlorine to form the chlorides (MCl4).The chlorides of the metals are then reacted with magnesium, yielding magnesium chloride and the metals.
Further purification is done by a chemical transport reaction developed by Anton Eduard van Arkel and Jan Hendrik de Boer. In a closed vessel, the metal reacts with iodine at temperatures of above 500 °C forming metal(IV) iodide; at a tungsten filament of nearly 2000 °C the reverse reaction happens and the iodine and metal are set free. The metal forms a solid coating at the tungsten filament and the iodine can react with additional metal resulting in a steady turn over.
-
- M + 2 I2 (low temp.) → MI4
- MI4 (high temp.) → M + 2 I2
Read more about this topic: Group 4 Element
Famous quotes containing the word production:
“The society based on production is only productive, not creative.”
—Albert Camus (1913–1960)
“By bourgeoisie is meant the class of modern capitalists, owners of the means of social production and employers of wage labor. By proletariat, the class of modern wage laborers who, having no means of production of their own, are reduced to selling their labor power in order to live.”
—Friedrich Engels (1820–1895)
“The production of obscurity in Paris compares to the production of motor cars in Detroit in the great period of American industry.”
—Ernest Gellner (b. 1925)