STUDY ON EXTRACTION MECHANISM OF SCANDIUM (III) WITH ALKYLPHOSPHONIC ACID MONOALKYL ESTER

The extraction mechanism of Sc(III) from hydrochloric acid solutions with s -octylphosphonic acid mono-iso-octyl ester(PT-19), iso-propylphosphonic acid mono-(1-hexyl-4-ethyl )octy 1 ester(PT-2) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (P507) in heptane is investigated. The extraction reaction of Sc(III)can be expressed respectively as follows:The equilibrium constants and thermodynamic functions of extraction reactions are calculated. The IR and NMR spectra of the extraction complexes of Sc(III)are discussed as well.