Behaviors of Adsorption and Elution on Amidoxime Resin for Gallium, Vanadium, and Aluminium Ions in Alkaline Aqueous Solution

Abstract

ABSTRACT For recovery of gallium from Bayer liquor, adsorption, and elution on amidoxime resin for gallium (Ga), vanadium (V), and aluminum (Al) ions in alkaline solution were systematically investigated by batch and column experiment. Amidoxime resin did not adsorb Al. The adsorption separation efficiency of Ga and V increased with increasing NaOH concentration and decreasing temperature and contact time. The adsorption kinetics of Ga and V are fit by a pseudo-second-order model. The adsorption isotherms of Ga and V could be fit well by the Langmuir model. Gallium was easily eluted using low concentration acid (1~2 mol/L H+), but it was difficult to elute V. Although high concentration acid could elute 70% of V, this treatment would destroy resin. With high NaOH concentration and a long eluting time, more than 50% of V could be eluted at temperatures greater than 50°C, and NaOH did no damage to the resin. The optimum condition of Ga separation from V and Al is at low temperature with short contact time and high NaOH concentration. After adsorption and desorption, a high-purity Ga is obtained, from which V can be recovered V by elution with a strong NaOH concentration at 50°C. FT-IR spectra and XPS showed that the adsorption mechanism of Ga was only related to interaction with oxygen atoms of amidoxime groups (C = NOH). Furthermore, the adsorption mechanism of V was related to both nitrogen and oxygen atoms of amidoxime groups that caused the difficulty of desorbing V from resin.