Question

(a) What are acidic and basic flux?

(b) Why does iron or zinc not occur free in nature?

Answer 1

(a)

Acidic flux:

Acidic flux are those flux which comes from substances like Lewis acid such as SiO_2, H₃PO₄, HCl etc.

Acidic flux is used in metal welding or extractive metallurgy or Smelting.

Silica (SiO₂) is used to remove basic earthly impurities (gangue) such as lime (CaO) or MgO.

Basic flux:

It is similar to Acidic flux but only difference is that we take basic substances like CaO for welding process or extractive metallurgy or Smelting.

Basic fluxes like lime (CaO), magnesium oxide (MgO) are used to remove acidic gangue such as SiO₂.

(b)
Iron and zinc are quite reactive and hence they do not occur in the free state. The compounds of metals found in nature are their oxides, carbonate and sulphides.