Selective separation and recovery of vanadium from acid leaching solution of polymetallic black shale as function of aminophosphonic acid

BACKGROUND: Acid leaching is an effective method to extract vanadium from polymetallic black shale. However, a large amount of metal impurities, especially iron and aluminum, which accompany V, are released during this process. RESULTS: In this study, a aminophosphonic acid chelating resin was used for the differential adsorption and desorption of vanadium, iron and aluminum ions to achieve deep separation and concentration of vanadium ions present in the acid leaching solution of polymetallic black shale. Results showed that vanadium adsorption efficiency reached 90.17% at a pH of 1.8. After differential adsorption and desorption, the V:Fe and V:Al concentration ratios increased from 1.84 to 64.53 and from 0.24 to 37.92, respectively. When a 2.5 mol L-1 NaOH solution was used as desorbent, the separation factors beta((V/Fe)) and beta((V/Al)) reached values of 694.22 and 452.29, realizing the selective separation and concentration of vanadium. CONCLUSION: It was found that the vanadium, iron and aluminum ions were selectively adsorbed onto the phosphonic acid functional groups (-PO(OH)(2)) and amino functional groups (-NH). The vanadium ions existed in the form of the polyvanadate (H2V10O284-), which can be directionally adsorbed onto -PO(OH)(2) under P-OH bond cleavage and coordination of H2V10O284- to the unsaturated phosphorus atom and then desorbed through the exchange between hydroxide anions OH- and H2V10O284-. The iron and aluminum ions cannot be desorbed by OH- because the iron and aluminum sulfate moieties FeSO4+ and AlSO4+ were capable of coordinating to the nitrogen atom of the N-H group via its lone electron pair. (c) 2022 Society of Chemical Industry (SCI).