Question

To remove basic impurities acidic flux is used while to remove acidic impurities ___ flux is used.

• A. acidic
• B. basic
• C. neutral
• D. none of these

Answer 1

Answer: (B)

basic

Flux is additional substance added during smelting operation to fuse non-fusible mass and to remove them.
To remove acidic impurities basic flux is used while basic impurities are removed by acidic flux.

$\underset{\text{Ferric oxide (basic impurity)}}{F{e}_2{O}_3}+\underset{\text{Silica (acid flux)}}{3Si{O}_2}\to \underset{\text{Ferric silicate (slag)}}{F{e}_2(Si{O}_3{)}_3}$

$\underset{\text{Phosphorus pentoxide (acidic impurity}}{P_2{O}_5}+\underset{\text{calcium oxide (basic flux)}}{3CaO}\to \underset{\text{Calcium phosphate (slag)}}{C{a}_3(P{O}_4{)}_2}$