Mono(2-ethylhexyl) phosphoric acid as an extractant for Cr(III) and its application to industrial waste

The paper contains details on the extraction behavior of Cr(III) along with Fe(III), Mg(II), Mn(II), Co(II), Ni(II), and Cu(II) from hydrochloric acid media employing the mono(2-ethylhexyl) phosphoric acid (H2MEHP-n-hexane sy stem. The effects of various parameters, such as the concentrations of acid , metal ion, and extractant, and the nature of diluent, on the extraction o f Cr(III) have been investigated. The data suggest that up to 90% Cr(III) c an be extracted in the 5 10(-3) to 0.1 M acid range. The extractant can hol d the metal ion up to one-tenth of its molar concentration. The extracting species in Cr(HR)(a), where H2R is H2MEHP. The partition data have been use d for binary separations of Cr(III) from some commonly associated metal ion s. The practical utility of the extractant has been demonstrated by recover ing Cr(III) from spent Fe-Cr catalyst and spent chrome liquor.