Editing Copper extraction (section)

===Hydrometallurgy===
[[File:Cu(Salox)2.png|thumb|left|upright=0.5|In some hydrometallurgical schemes, copper(II) is extracted from aqueous solution as by complexation to [[salicylaldoxime]].]]

Oxidised copper ores include carbonates such as [[azurite]] and [[malachite]], the silicate [[chrysocolla]], and sulfates such as [[atacamite]]. In some cases, sulfide ores are allowed to degrade to oxides. Such ores are amenable to hydrometallurgy. Specifically, such oxide ores are usually extracted into aqueous [[sulfuric acid]], usually in a [[heap leaching]] or [[dump leaching]]. The resulting pregnant leach solution is purified by solvent extraction (SX). It is treated with an organic solvent and an organic chelators. The chelators bind the copper ions (and no other ions, ideally), the resulting complexes dissolve in the organic phase. This organic solvent is evaporated, leaving a residue of the copper complexes. The copper ions are liberated from the residue with sulfuric acid. The barred (denuded) sulfuric acid recycled back on to the heaps. The organic ligands are recovered and recycled as well. Alternatively, the copper can be precipitated out of the pregnant solution by contacting it with scrap iron; a process called [[Cementation (metallurgy)|cementation]]. Cement copper is normally less pure than SX-EW copper.<ref>{{cite journal |title=Co-extraction of Cations and Anions in Base Metal Recovery |year=2007 |last1=Tasker |first1=Peter A. |last2=Tong |first2=Christine C. |last3=Westra |first3=Arjan N. |journal=Coordination Chemistry Reviews |volume=251 |issue=13–14 |pages=1868–1877 |doi=10.1016/j.ccr.2007.03.014}}</ref>