Why should the metal sulphides and carbonates be converted tometal oxides in the process of extraction of metal from them?

The extraction of metals from their ores involves several steps. For metal sulfides and carbonates, the first step is often to convert them into metal oxides. This is done for several reasons:

1. Reduction Ease: Metal oxides are easier to reduce. This means that it's easier to remove oxygen from a metal oxide than it is to remove sulfur from a metal sulfide or carbon dioxide from a metal carbonate.

2. Stability: Metal oxides are more stable than metal sulfides or carbonates. This means that they are less likely to react with other substances in the environment, which makes the extraction process more efficient.

3. Energy Efficiency: The process of converting metal sulfides or carbonates to metal oxides is often carried out by roasting or calcination, which are energy-efficient processes.

4. Purity: Converting sulfides and carbonates to oxides helps in removing impurities. The impurities can be removed as gases during the conversion process.

So, in summary, the conversion of metal sulfides and carbonates to metal oxides in the process of metal extraction makes the process more efficient, easier, and results in a purer metal product.