Which of the following is not a basic flux?

Match the items of List-$I$ with those of List-$II$ and choose the correct option given below.

List-$I$	List-$II$
$A$. Calcination	$1$. Galena
$B$. Roasting	$2$. Magnetite
$C$. Magnetic separation	$3$. Pyrometallurgy
$D$. Carbon reduction of metal oxide	$4$. Malachite

The electrochemical extraction of aluminum from bauxite ore involves:

To obtain steel entirely free from sulphur and phosphorus,the process used is

The correct option$(s)$ related to the extraction of iron from its ore in the blast furnace operating in the temperature range $900-1500 \ K$ is(are):
$(A)$ Limestone is used to remove silicate impurity.
$(B)$ Pig iron obtained from blast furnace contains about $4 \%$ carbon.
$(C)$ Coke $(C)$ converts $CO_2$ to $CO$.
$(D)$ Exhaust gases consist of $NO_2$ and $CO$.

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: