Question

How is leaching carried out in case of low grade copper ores?

Answer 1

Acid in presence of air is used to leach out copper from low grade copper.
$Cu+2H^{+}+0.5O_2\to C{u}^{2+}+2H_{2}O$

Solution is then treated with scrap iron or hydrogen.
$C{u}^{2+}+H_2\to Cu+2H^{+}$