How is zinc extracted from its ores?

Zinc is extracted from its ores by the process of roasting and reduction with carbon.

Zinc is found in several ores, the principal ones being zinc blende (zinc sulphide) and calamine (zinc silicate). The extraction process involves the following steps:

1. Concentration: The ore is crushed and then concentrated by froth-floatation process.

2. Roasting: The concentrated ore is then roasted in the presence of excess air at about 1200 K to convert zinc sulphide into zinc oxide.
2ZnS + 3O2 → 2ZnO + 2SO2

3. Reduction: Zinc oxide is mixed with powdered coke and heated to 1673 K in a fire clay retort in which ZnO is reduced to zinc metal.
ZnO + C → Zn + CO

The zinc thus obtained is impure and is refined by distillation. The impure zinc is heated in a retort at a temperature above 1000 K where it vaporises, leaving behind non-volatile impurities. The vapours of zinc are condensed to obtain pure zinc.

This process of extraction of zinc from its ores is called Pyrometallurgy, as the extraction is carried out using heat. It's worth noting that these steps are not only important for the extraction of zinc, but also for other metals. The details of the process may vary slightly depending on the type of ore used.

Remember, safety is paramount in these processes as they involve high temperatures and potentially harmful substances. Always ensure you're wearing appropriate protective equipment and working in a well-ventilated area.