Using an Interdigital Micromixer for Separation of In3+ from Zinc Hydrometallurgical Process with D2EHPA as an Extractant

Experiments were performed in an interdigital micromixer with 30 microchannels (40 μm width of each channel) to separate In³⁺, Fe³⁺ and Zn²⁺ from sulfate solutions using Di-(2-ethylhexyl)phosphoric acid (D2EHPA) as the extractant. The effects of pH, extractant concentration and flow rate on the extraction efficiency and flow rate on mass transfer coefficient of In³⁺, Fe³⁺ and Zn²⁺ were investigated. At a phase flow rate of 7.0 mL/min and initial solution pH of 0.423, the extraction efficiency of In³⁺, Fe³⁺ and Zn²⁺ was 99.29%, 3.43% and 2.54%, respectively and mass transfer coefficient of In³⁺, Fe³⁺ and Zn²⁺ was 144.307 s^-1,1.018 s^-1 and 0.750 s^-1. Then, the loaded organic phase was stripped in an interdigital micromixer. At a phase flow rate of 9.0 mL/min and HCl concentration of 160 g/L, stripping efficiency of In³⁺ was 98.92% and mass transfer coefficient of In3+ was 169.808 s^-1, while concentration of Fe³⁺ and Zn²⁺ was lower than 0.005 g/L with good separation of In³⁺ from Fe³⁺ and Zn²⁺.