Solvent extraction of In3+ with microreactor from leachant containing Fe2+ and Zn2+

The microreactor has been developed for a wide range of applications because of many advantages, such as high mass transfer efficiency, low energy consumption and the closed and safe system. The application of microreactors in the traditional hydrometallurgy extraction process is expected to overcome difficulties such as co-extraction of impurities, large consumption of extractant and hidden fire risks. In this study, the extraction and separation efficiency of In3+ from a complex sulfate solution containing impurities, such as Fe2+ and Zn2+, were studied. The microreactor extraction was carried out in a Pyrex microchip, and the organic phase was prepared with the extractant di(2-ethylhexyl) phosphoric acid (D2EHPA) diluted in 260# kerosene. The results showed that with only 0.55 s contact between the organic and aqueous phases, the extraction ratio of In3+ can reach 90.80%, while only 0.16% of Fe2+ and 0.22% of Zn2+ were co-extracted; the average mass transfer speed of In3+ was calculated as high as 0.34 g.m(-2).s(-1). Compared with the traditional mixing settler process, microreactor extraction has advantages of higher extraction ratio of In3+, lower trend of co-extraction of the impurities and emulsification.