Generally carbonate ores produces effervescence with dil HCl
This is due to liberation of carbon dioxide on reaction of carbonate of ore with dil HCl.
In order to obtain metal from the enriched ore
we first convert the ores into their oxides so that they can be reduced easily. So the oxides of a metal are more reducible as compared to other compounds.
For carbonated ores with heat the ores in absence of oxygen which converts them to oxides.
Hence
a) the first step will be calcination. Calcination is heating of ore in absence of ore which is used for carbonated ores
for example
[tex]CaCO_{3} ---> CaO(s) + CO_{2} (g)[/tex]
b) the second step will be reduction of these oxides to give free metal
It can be done by heating in presence of carbon.
So we need to reduce the oxide obtained after calcination.
