Copper matte contains

Refractory materials are generally used in furnaces because

The main reactions occurring in a blast furnace during the extraction of iron from haematite are $....$.
$(i)$ $Fe_2O_3 + 3CO \to 2Fe + 3CO_2$
$(ii)$ $FeO + SiO_2 \to FeSiO_3$
$(iii)$ $Fe_2O_3 + 3C \to 2Fe + 3CO$
$(iv)$ $CaO + SiO_2 \to CaSiO_3$

For which of the following metals is the self-reduction process $NOT$ used?

Which of the following is used to reduce magnetite $(Fe_3O_4)$ to obtain iron?

Which one of the following is used as an acid flux in metallurgy?