Metallurgy is the process of

Which among the following statement$(s)$ is(are) true for the extraction of aluminium from bauxite?
$A$. Hydrated $Al_2O_3$ precipitates,when $CO_2$ is bubbled through a solution of sodium aluminate.
$B$. Addition of $Na_3AlF_6$ lowers the melting point of alumina.
$C$. $CO_2$ is evolved at the anode during electrolysis.
$D$. The cathode is a steel vessel with a lining of carbon.

Spiegeleisen is an alloy of

Which alloy contains a non-metal?

Given below are two statements.
Statement $I$: Pig iron is obtained by heating cast iron with scrap iron.
Statement $II$: Pig iron has a relatively lower carbon content than that of cast iron.
In the light of the above statements,choose the correct answer from the options given below.

The form of iron having the highest carbon content is