Extraction behavior of gold from hydrochloric acid solutions with ionic liquids as extractants

The extraction mechanism of gold(III) with ionic liquids as extractants has been investigated in a liquid-liquid extraction system. Ionic liquids were found to possess a high extraction potential for gold. The composition of the complex between gold and an ionic liquid was elucidated by slope analysis and Job's method. The gold exists as a tetrachloroaurate anion complex in hydrochloric acid solutions, which reacted with an ionic liquid molecule in chloroform and was extracted into the organic solutions. Furthermore, gold could be separated from copper in an acidic chloride medium by using the ionic liquid as the extractant.