Question
Explain the following terms:
1. Concentration of ores
2. Roasting
3. Calcination
4. Refining
1. Concentration of ores
2. Roasting
3. Calcination
4. Refining
✓
Answer
1. Concentration of ores: The process of separating gangue from the other ores is called concentration of ores.
2. Roasting: The process of heating an ore to a high temperature in excess of air and converting it into its oxide is called roasting.
Examples: ZnS (zinc blend), PbS (Galena)
$
ZnS \underset{\text { oxidation }}{\stackrel{ O _2(\text { heat) }}{\longrightarrow}} ZnO
$
3. Calcination: The process of heating an ore in a limited supply of air and converting it into its oxide is called calcination.
Example: Zinc carbonate $\left( ZnCO _3\right)$
$ZnCO _3 \rightarrow ZnO + CO _2 \uparrow$
4. Refining: The metal obtained by chemical reduction contains impurities. The process of electrolysis method is used to obtain pure metals from impure metals is known as refining.
2. Roasting: The process of heating an ore to a high temperature in excess of air and converting it into its oxide is called roasting.
Examples: ZnS (zinc blend), PbS (Galena)
$
ZnS \underset{\text { oxidation }}{\stackrel{ O _2(\text { heat) }}{\longrightarrow}} ZnO
$
3. Calcination: The process of heating an ore in a limited supply of air and converting it into its oxide is called calcination.
Example: Zinc carbonate $\left( ZnCO _3\right)$
$ZnCO _3 \rightarrow ZnO + CO _2 \uparrow$
4. Refining: The metal obtained by chemical reduction contains impurities. The process of electrolysis method is used to obtain pure metals from impure metals is known as refining.
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