... and produces a solution of copper sulphate which is diluted and impure (Chemical Storylines). Solvent extraction techniques are used to recover the copper ions from the solution by a process of ligand exchange solvent extraction. (Article 2) The ligand, dissolved in an organic solvent such as kerosene is immiscible in water. Cu2+(aq) + 2LH (organic) = CuL2(organic) +2H+(aq) (L represents the ligand) The copper is removed from a low concentration in water to a high concentration in the solution. Mixing the organic solution with a small volume of concentrated acid reverses the process and pushes the Cu2+ ions back into the aqueous solution increasing their concentration. The concentrated copper solution is then sent to through electro winning cells with cathodes for recovery as copper plates (Copper mining & processing). The remaining leaching solution is allowed to flow into an open pond where it is recharged by the oxidation of the Fe2+ ions ...

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