Abstract
The feasibility to recover indium (In) from discarded liquid crystal display (LCDs) panels by solvent extraction (SX) and a hollow fiber supported liquid membrane with strip dispersion (SLM-SD) system was investigated in this study. Di-(2-ethylhexyl)phosphoric acid (D2EHPA) was used as the extractant and the mobile carrier in SX and SLM-SD. The effect of different parameters such as pH, concentration of D2EHPA and stripping agents has been investigated for indium extraction. The average amount of indium in LCD screen was found to be 330 mg/kg and 70% of this indium was easily leached out by 3 M HCl in 30 min. An increase in the D2EHPA concentration from 0.025 to 0.25 M increased the extraction of indium and 79% of indium can be recovered by back-extraction with 2 M hydrochloric acid. For the SLM-SD system, more than 94% of indium can be recovered within 20 min under the same operating conditions. This indicates that the SLM-SD was more efficient for indium extraction than SX. However, a poor separation of iron and indium resulted on increasing the extraction time. Hence, process optimization for iron removal must be explored in a future work.
