Characterization strategy of polymeric transition metal species transformation for high-purity metal recovery

Abstract

The aqueous metal species with similar chemical properties are usually extracted together, limiting deep separation for high-purity metal. However, rare attention has been paid to metal speciation characterization and transformation during separation. Herein, the hydrolysis evolution of polymeric metal species was investigated systematically by electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). The transformation evolutions were visualized with respect to characteristic vanadium species (V1, V2, V3, V4 and V10), chromium species (Cr1 and Cr2), tungsten (W1, W2, W4, W6 and W10) and molybdenum (Mo1, Mo2 and Mo4) species. The key characteristics (such as specfic pHs and concentrations) for speciation variation were revealed. The polymerization behavior of several transition metals can be semiquantitative characterized by this strategy. The sufficient speciation transformation provides a solid base for metal speciation chemistry, and guides further development of high-purity metal recovery.