Separation of rhenium and molybdenum from autoclave acid-leach liquor of molybdenite concentrate using bifunctional ionic liquid [A336][Cy272] in xylene

Bifunctional ionic liquids (Bif-ILs) are a class of liquids in which both cations and anions actively participate in the extraction process through chemical bonds. These liquids exhibit high selectivity and stability. This study investigated the solvent extraction of molybdenum (Mo) and rhenium (Re) using the Bif-IL [A336][Cy272], diluted in xylene. Various parameters, such as stirring speed, temperature, aqueous-to-organic (A/O) phase volume ratio, contact time, acid concentration and extractant concentration, were examined to determine their effects on the extraction recovery and separation factor of Mo and Re. The highest Re/Mo separation factor (SF_Re/Mo = 114) and the highest percentage of Re extraction (91 %) were achieved from a leach solution containing ∼5.5 g L⁻¹ Mo and 6.6 × 10⁻² g L⁻¹ Re. These results were obtained under optimized conditions: [A336][Cy272] at 2.5 % (v/v) in the organic phase, pH = 0.35, A/O = 1/1, contact time = 10 min, stirring speed = 300 rpm, and temperature = 298 K. The extraction mechanism for Mo and Re was studied using the slope analysis method, which revealed that the process follows an ion-association mechanism. The Re stripping into the aqueous phase was efficient when 1 M (NH₄)₂CO₃ was applied. The Re stripping efficiency under the examined conditions was 99.7 %, while the stripping of Mo and other impurities was negligible.