Extraction of iron(III), gold(III), gallium(III), thallium(III), antimony(V) and antimony(III) from hydrochloric acid solution with crown ethers

Abstract

Chloroform solutions of dicyclohexyl-18-crown-6 (DC18C6), dibenzo-18-crown-6 (DB18C6) and 18-crown-6 (18C6) efficiently extracted iron(III), gold(III), gallium(III), thallium(III) and antimony(V) from solution in hydrochloric acid. Extraction with 15-crown-5 (15C5) and 12-crown-4 (12C4) was poor. Antimony(III) in the presence of titanium(III) chloride was efficiently extracted only with DC18C6. When tervalent iron, gold, gallium and thallium were extracted from acidic lithium chloride solution, even 15C5 and 12C4 gave good extractabilities. The molar ratio of crown ether to the metal ions, except antimony(III), in the extracted species is probably 1 : 1, and the metals are probably extracted as chloro complexes, e.g., HFeCl₄ and LiFeCl₄. Iron and gallium in aluminium-base alloys were determined after their separation by DC18C6 extraction.