Selective separation of rhenium from oxygen-pressure leach solution of molybdenite concentrate using modified D201 resin: Experiments and theoretical calculations

Abstract

Recovering rhenium from highly acidic rhenium-containing leach solutions is challenging for most resins, particularly in multiplexed systems. Herein, we introduce a scheme for selectively obtaining rhenium from a multielement solution containing high concentrations of sulfuric acid using modified D201 resin. Considering the dosage of resin and parameters such as pH and adsorption temperature, the adsorption efficiencies under optimal conditions for rhenium, molybdenum, iron, and cerium were 97.46 %, 0.38 %, 0.94 %, and 1.10 %, respectively. The selective recovery mechanism of rhenium was investigated by fitting the experimental data to kinetic and adsorption isotherm models. The pseudo-second-order and Langmuir models better fit results corresponding to the experimental data, which indicates monolayer chemisorption of ReO4− formed on the resin surface. Meanwhile, various characterizations such as SEM-EDS, FTIR, XPS, etc., indicate that ReO4− initially combines with the protonated −CHN+H2CH2Cl on the modified resin surface and then undergoes ion exchange reaction with doped Cl−. Furthermore, because of the diverse forms and similar properties of molybdenum and rhenium ions in acidic solutions, a theoretical model based on density functional theory was used to simulate the selective adsorption process in leach solution with a pH of 1.7. The simulation results demonstrate a highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap, observed in the following order: ΔEMoO22+ = ΔEReO4− < ΔEMoO42− < ΔEMo7O246−, which implies that MoO22+ and ReO4− were most likely to transition from their ground states to excited states and react with the electron donor and acceptor groups, respectively. Compared with MoO42−, ReO4− is more likely to react with the electron acceptor group and provides the corresponding methods and a theoretical reference for selective separation of rhenium in multielement solutions.