Abstract
Solvent extraction of molybdenum(VI) and tungsten(VI) with alpha-hydroxy oxime, 5,8-diethyl-7-hydroxydodecan-6-one oxime (LIX 63) from acidic and neutral solutions was studied. The rate of extraction of molybdenum(VI) was much higher than that of tungsten(VI). Molybdenum(VI) was almost quantitatively extracted from nitric acid solutions up to 5 M, and the extraction decreased at higher acid concentrations. The extraction of tungsten was rather low at short contact time.
The separation of molybdenum(VI) from a large amount of tungsten(VI) was accomplished around pH 1 by contacting for 10 minutes, yielding the separation factor of alpha(Mo)(= D-Mo/D-W) = 166. Molybdenum(VI) was separated from several metal ions such as Fe(III), Co(II), Ni(II), Zn(II) and Cu(II). At high nitric acid concentrations, tungsten(VI) was preferentially extracted for a long shaking time. The elemental analyses of the extracted species and their IR and NMR spectra suggest the coordination of two molecules of LIX 63 onto MoO22+ and WO22+.