In(III) hydrometallurgical recovery from secondary materials by solvent extraction

• The recovery of In(III) by using SX with four different extractants is investigated.
• IONQUEST 801 and D2EHPA allow to obtain the highest In(III) extraction yields.
• The extraction behavior of some commonly associated metal ions is also investigated.
• Both D2EHPA and IONQUEST 801 do not allow Fe–In separation in the extraction stage.
• Fe–In separation can be achieved in the stripping stage.

Indium can be recovered from the residues of zinc and lead refineries and from electronic scrap. In the hydrometallurgical processes the main problem is separating In(III) from Fe(III) that are both present in the leaching solutions. In this work the extraction of In(III) from HCl, H2SO4, and HNO3 media using D2EHPA, LIX 984, CYANEX 272 and IONQUEST 801 solutions in kerosene is investigated. In(III) is quantitatively extracted from every considered acidic solution by means of IONQUEST 801 even at quite low pH.D2EHPA allows to obtain extraction yields very similar to those obtainable by means of IONQUEST 801 except in the extraction tests from HCl solutions. The extraction behavior of some commonly associated metal ions such as Fe(III), Cu(II) and Zn(II), has also been investigated with the aim of attaining high extraction selectivity. The results highlighted that both D2EHPA and IONQUEST 801 do not allow a complete Fe(III)–In(III) separation, while In(III) can be effectively separated from Cu(II) and Zn(II). The results highlighted that an effective Fe(III)–In(III) separation can be performed in the stripping stage.