Liquid–liquid extraction of chloroauric acid is used for the recovery, concentrating, purification, and analytical determinations of gold. Of great importance is the extraction of HAuCl4 from hydrochloric medium by oxygen-containing extractants, such as alcohols, ketones, ethers and esters. The concentration of gold(III) in the extracts may exceed 1 mol/L.(...) The most frequently used extractants for this purpose are dibutyl glycol, methyl isobutyl ketone, tributyl phosphate, dichlorodiethyl ether (chlorex).

The extraction of gold(III) from nitric acid solutions by means of oxygen-containing solvents (di-isopropyl, diethyl and dichloroethyl ethers, methyl isobutyl and methyl isopropyl ketones, n-amyl acetate and n-amyl alcohol) is described. The most effective of these extractants are di-isopropyl ether (in the range 5.5–10 M nitric acid) and diethyl ether (4–10 M nitric acid). In both cases, maximum extraction is ca. 95% in a single pass.