Bessemerisation is carried out for:
$I$: $Fe$
$II$: $Cu$
$III$: $Al$
$IV$: Silver

Give the correct order of initials $T$ or $F$ for following statements. Use $T$ if statement is true and $F$ if it is false.
$(i)$ In Goldschmidt thermite process,aluminium acts as a reducing agent.
$(ii)$ $Mg$ is extracted by electrolysis of aqueous solution of $MgCl_2$.
$(iii)$ Extraction of $Pb$ is possible by carbon reduction method.
$(iv)$ Red Bauxite is purified by Serpeck's process.

Which of the following changes involve more than two metallurgical processes?

What is known as Thomas slag?

In aluminium extraction by the Bayer process, alumina is extracted from bauxite by sodium hydroxide at high temperature and pressure: $Al_2O_{3(s)} + 2 OH^-_{(aq)} + 3 H_2O_{(l)} \rightarrow 2 [Al(OH)_4]^-_{(aq)}$. Solid impurities such as $Fe_2O_3$ and $SiO_2$ are removed and then $[Al(OH)_4]^-$ is reprecipitated: $2 [Al(OH)_4]^-_{(aq)} \rightarrow Al_2O_3 \cdot 3 H_2O_{(s)} + 2 OH^-_{(aq)}$. In the industrial world: