Complexing and extraction of elements from trichloroacetate solutions with diantipyrylmethanes

Extraction is studied of scandium, indium, zirconium, hafnium, thorium and other elements from trichloroacetate solutions with diantipyrilmethanes; a method of complexometric determination of scandium has been developed. A significant impact of acidity on the metal extraction efficiency has been established. At pH<3 the metallic ions are extracted in the form of implantation complexes by addition mechanism, and at pH>3 this occurs by cationic exchange mechanism. The optimal conditions of quantitative extraction of scandium involve the 30-fold amount of trichloroacetate and 10-fold amount of the extragent. The composition of the scandium-base ionic associate to be extracted corresponds to the formula [ScA2(CCl3COO)2]CCl3COO. Zn, Hf and Fe complexes have a similar formula. Scandium extraction efficiency exceeds 90% when use is made of diantipyrilmethane, its homologues and phenyl derivatives. TBP gives as low as 80% scandium extraction. Scandium determination is not prevented by rare earths, Fe(2), Zn, Cd, Ni, Al, V(4), Mn(2), Mg, alkaline and alkaline-earth elements