Extraction of Copper from Low Grade Ore and Scraps:-

Copper is extracted by hydrometallurgy from low grade ore. Copper is extracted by leaching it with an acid when copper metal goes into solution as Cu⁺² ions. The solution containing Cu⁺² ions is than treated with scrap iron or H₂ gas.

                Hence Cu can be displaced from the Cu⁺² ions by Fe or H₂.

“Hydrometallurgy is the process of dissolving an ore in a suitable reagent followed by extraction of the metal either by electrolysis or displacement or the metal by a more electropositive metal.”

Ag and Au are also extracted by this method. In the process of leaching Ag and Au are Converted into Na[Ag(CN)₂] and K[Au(CN)₂] complexes. These complexes when are treated with Zn powder, they are displaced by Zn.

2Na[Ag(CN)₂] + Zn ⟶ Na₂[Zn(CN)₄] + 2Ag

And        2K[Au(CN)₂] + Zn ⟶ K₂[Zn(CN)₄] + 2Au