Abstract: The extraction of Au（III） from aqueous solution with imidazolium-type ionic liquid， 1-hexadecyl-3-methylimidazolium bistrifluoromethanesulfonimide （［C16mim］［NTf₂］）-n-pentanol was investigated. The effects of pH， extractant concentration （g/L）， volume ratio between ionic liquid phase and aqueous solution （mass-volume ratio of ［C16mim］［NTf₂］ to n-pentanol on the extraction of Au（III） were analyzed. The results indicated that the extraction rate of Au（III） increases with the increase of the volume ratio between ionic liquid phase and aqueous solution and pH of aqueous solution， the extraction rate of Au（III） increases with the increase of extractant concentration when pH<1.6. ［C16mim］［NTf₂］ has obvious selective extraction effect on Au（III）. The extraction rate of Au （III） can reach more than 90% under the condition of the concentration of Au（III） in aqueous solution is 0.05 g/L， volume ratio between ionic liquid phase and aqueous solution of 1∶3， leaching gold solution of pH=1.6～2.0， ［C16mim］［NTf₂］ concentration of 5 g/L， extraction time of 2 min at room temperature， and the selectivity coefficient β of Au for Al， Cu， Fe， Zn is 466， 780， 1 118 and 1 404 respectively.

Key words: Ionic liquids, ［C16mim］［NTf₂］, Extraction, Au（Ⅲ）