Extraction of Metals:
Different methods are used for extracting metals belonging to category of highly reactive metals, moderately reactive metals and less reactive metals. This is because the extraction of a metal from its concentrated ore is essentially a process of reduction of the metal compound present in the ore. For example: Manganese metal is obtained by the reduction of its oxide with aluminium powder and not carbon. This is because carbon is less reactive than manganese. Carbon, which is a non-metal, is more reactive than zinc and it can be placed just above Zn in the reactivity series. Hence, carbon can reduce the oxides of zinc and all other metals below zinc to form metals. The reactivity of elements differs for different metals.
Extraction of Less Reactive Metals:
The less reactive metals are extracted by the reduction of their oxides by heat alone.
Example: Mercury (II) sulphide ore is roasted in air when mercury (II) oxide is formed. When this mercury (II) oxide is heated to about 300° C, it decomposes to form mercury metal.
Extraction of Moderately Reactive Metals:
The moderately reactive metals in the middle of the reactivity series are extracted by the reduction of their oxides with carbon, aluminium, sodium or calcium.
It is easier to obtain metals from their oxides (by reduction) than from carbonates or sulphides. So, before reduction can be done, the ore is converted into a metal oxide. The concentrated ores can be converted into metal oxides by the process of calcination or roasting.
Calcination is the process in which a carbonate ore is heated strongly in the absence of air to convert it into a metal oxide.
For example: When zinc carbonate is heated strongly in the absence of air, it decomposes to form zinc oxide and carbon dioxide.
Extracting Metals towards the Top of the Activity Series:
Metals high up in the reactivity series are very reactive. These metals have a strong affinity for oxygen. So, oxides of sodium, magnesium, calcium and aluminium cannot be reduced by carbon.
These metals are obtained by electrolytic reduction.
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Meghna Thapar 5 years, 10 months ago
Extraction of Metals:
Different methods are used for extracting metals belonging to category of highly reactive metals, moderately reactive metals and less reactive metals. This is because the extraction of a metal from its concentrated ore is essentially a process of reduction of the metal compound present in the ore. For example: Manganese metal is obtained by the reduction of its oxide with aluminium powder and not carbon. This is because carbon is less reactive than manganese. Carbon, which is a non-metal, is more reactive than zinc and it can be placed just above Zn in the reactivity series. Hence, carbon can reduce the oxides of zinc and all other metals below zinc to form metals. The reactivity of elements differs for different metals.
Extraction of Less Reactive Metals:
The less reactive metals are extracted by the reduction of their oxides by heat alone.
Example: Mercury (II) sulphide ore is roasted in air when mercury (II) oxide is formed. When this mercury (II) oxide is heated to about 300° C, it decomposes to form mercury metal.
Extraction of Moderately Reactive Metals:
The moderately reactive metals in the middle of the reactivity series are extracted by the reduction of their oxides with carbon, aluminium, sodium or calcium.
It is easier to obtain metals from their oxides (by reduction) than from carbonates or sulphides. So, before reduction can be done, the ore is converted into a metal oxide. The concentrated ores can be converted into metal oxides by the process of calcination or roasting.
Calcination is the process in which a carbonate ore is heated strongly in the absence of air to convert it into a metal oxide.
For example: When zinc carbonate is heated strongly in the absence of air, it decomposes to form zinc oxide and carbon dioxide.
Extracting Metals towards the Top of the Activity Series:
Metals high up in the reactivity series are very reactive. These metals have a strong affinity for oxygen. So, oxides of sodium, magnesium, calcium and aluminium cannot be reduced by carbon.
These metals are obtained by electrolytic reduction.
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