Question

how is copper extracted from a low grade ore of it

Answer 1

copper was obtained from low grade ire through the process of leaching using acid or bacteria

Answer 2

1) Copper can be obtained from low grade ore through the process of leaching using acid or bacteria (leaching is a process in which ore is treated with suitable reagent which dissolves ore but not the impurities).
2) Reduction:- Then this solution containing copper is treated with scrap iron or H2 to get the copper.