Copper extraction by solvent extraction has been practiced for many decades using NTA and LIX reagents. Although other processes, such as electrorefining, have been developed to extract copper from ore, solvent extraction is more economical and efficient. The process consists of extracting copper from ore using an organic solvent, usually an aromatic hydrocarbon such as toluene. The copper is then separated from the toluene by acidification, precipitation, or electrodeposition.
The copper extraction process begins with a finely ground ore, which is treated with an aqueous reagent, known as a lixiviant. The lixiviant leaches out the copper, which is then recovered either as a copper-containing solution, or as a copper-containing solid that is subsequently separated by filtration. The solution is then treated with an organic solvent, known as an extractant, that selectively removes the copper from the leach solution.
Following extraction, the copper is either recovered as a copper-containing solution or as an orange-brown solid that is separated from the extractant by precipitation. The precipitate can be further refined by acid leaching or electrorefining before being sent for further processing, such as smelting or refining. Alternatively, the copper can be recovered as a copper-containing solution, which is further treated with a solvent to form copper hydroxide or copper sulphate precipitates. The copper-containing solution can be further processed using a thiourea reagent, which selectively extracts the copper into a separate organic phase.
The reagents used in solvent extraction processes can vary, depending on the target metal being extracted. For copper extraction, a variety of aromatic hydrocarbons, such as toluene, have been used. Other aromatic hydrocarbons, such as xylene, ethylbenzene and heptane, are also suitable for copper extraction. In addition, many organic extractants, such as amines, phosphonates, and carboxylates, have been developed for use in the extraction of copper.
In summary, solvent extraction is a cost-effective and efficient method of recovering copper from ore. The process consists of treating the ore with an aqueous reagent, extracting the copper from the leached solution, and then separating the copper from the extractant. Depending on the reagents used, the copper can be recovered as either a copper-containing solution or a copper-containing solid. The copper-containing solution can be further treated with a reagent to form a copper hydroxide or copper sulphate precipitate. Finally, the precipitate can be further processed using electrorefining or acid leaching to produce a high-purity copper concentrate.
