Solvent extraction of gallium (III) and aluminum (III) from alkaline solutions by 7-alkylated 8-hydroxyquinoline

Abstract

Distribution isotherm has been determined for the extraction of gallium (III) and aluminum (III) from sodium hydroxide solusions by 7-(5, 5, 7, 7-tetramethyl-1-octen-3-yl)-8-hydroxyquinoline (Kelex 100, HQ) in kerosene under various conditions.
It is found that both metals are taken up, through a cation-exchange mechanism:
M(OH)₄^-(aq)+3HQ(org)_??_MQ₃(org)+OH^-(aq)+3H₂O(aq)
where M=Ga and Al. Gallium (III) is confirmed to be separated effectivily by means of the solvent extaction of gallium and aluminum by Kelex 100 from aqueous solutions containing 0.1-6mol dm^-3 sodium hydroxide, due to the large differents in the extractability and extraction rate by Kelex 100 for gallium and aluminum.