Mutual separation of indium, gallium, and zinc with the amic acid-type extractant D2EHAG containing glycine and amide moieties

Abstract

Solvent extraction of indium (In3+), gallium (Ga3+), and zinc (Zn2+) was investigated using N-[N,N-di(2-ethylhexyl)aminocarbonylmethyl]glycine (D2EHAG) and N-[N,N-di(2-ethylhexyl)aminocarbonylmethyl]-sarcosine (D2EHAS) which we have developed recently. Indium and gallium were selectively extracted from zinc under high acid conditions (0 > pH ≥ 2.0), and easily stripped using an acidic solution such as 2 mol dm-3 HNO3. The extraction behavior was compared to that of N,N-dioctyldiglycol amic acid (DODGAA), which has a similar molecular structure to D2EHAG, a commercial alkyl monocarboxylic acid extractant, neodecanoic acid (Versatic 10), or an organophosphorus extractant, di(2-ethylhexyl) phosphoric acid (D2EHPA). Based on the results, D2EHAG and D2EHAS were found to be useful for the separation of In3+ and Ga3+ from Zn2+. The extraction mechanisms of these ions with D2EHAG were investigated through slope analysis and loading tests.