Astrid Rahmawati, Kurniawan Adi Kuncoro, Suryadi Ismadji, Jhy-Chern Liu
Subcritical water extraction (SWE) was applied to extract indium (In) from indium tin oxide (ITO) scrap. Four organic acids, acetic acid, gluconic acid, citric acid (CA) and etidronic acid (EA), were used at a solid-to-liquid ratio (S/L) of 10 g L-1. Neither acetic acid nor gluconic acid yielded significant extraction of indium. A total of 70.71 % and 96.93 % of indium was extracted using 1 M of CA and EA respectively at 150 °C and a final pressure of 18-19 bar within 30 min. The extraction efficiency of In was shown to increase with the increase in acid concentration and in temperature. Compared with conventional extraction methods, SWE was more effective using less concentrated acids and required a shorter reaction time. © 2020 CSIRO.
Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei, 106, Taiwan; Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Kalijudan 37, Surabaya, 60114, Indonesia