Lead is mainly extracted by

What is the role of limestone during the extraction of iron from haematite ore?

The Ellingham diagram for zinc,magnesium,and carbon converting into corresponding oxides is shown below. To make the following reduction process spontaneous,the temperature should be:
$ZnO + C \to Zn + CO$

The role of fluorspar $(CaF_2)$, which is added in small quantities in the electrolytic reduction of alumina $(Al_2O_3)$ dissolved in fused cryolite $(Na_3AlF_6)$, is:

Predict the physical state of the metal $M$ obtained in the following reduction reaction shown by the Ellingham diagram: $MO(s) + C(s) \rightarrow M(?) + CO(g)$.

Smelting is done in