Give the steps involved in the extraction of metals of low and medium reactivity from their respective sulphide ores.
Extraction of less reactive metals: The less reactive metals are extracted by the reduction of their oxides by heating alone.
For example: Extraction of Mercury: Mercury’ is a metal oflow reactivity. Cinnabar, i.e. mercury (II) sulphide is the ore of mercury. It is heated in air so that it is oxidized to produce mercury (II) oxide. After that, mercury oxide is reduced to obtain mercury. The following reactions are involved in this process:
Extraction of metals of medium reactivity series : The moderately’ reactive metals are extracted by the reduction of their oxides with carbon, aluminium, sodium or calcium. The concentrated ores can be converted into metal oxide by the process of calcination or roasting.
For example : Extraction of Zinc : Zinc is in the middle of the reactivity series. It is found in the form of zinc blende which is Zinc Oxide. It is first heated in the presence of air to obtain Zinc Oxide. This process can be shown by following equation:
After that, Zinc Oxide is reduced to obtain pure zinc metal. The reduction is done in the presence of carbon. This can be shown by following equation: