Continuous and Selective Separation of Heavy Metals Using Shock Electrodialysis

Abstract

Selective separation of chemically and physically similar heavy metals is an important capability in extractive metallurgy and minerals processing. Metals with complex water chemistries present a fundamental challenge for selective hydrometallurgy, which often necessitates the implementation of complicated, many-step, and reagent-intensive processing techniques to achieve these separations. In this article, we use shock electrodialysis to continuously and selectively separate heavy metals, including cobalt, nickel, vanadium, molybdenum, and tungsten, from a synthetic leach liquor in a two-step process. In the first step, cobalt and nickel are separated from the other metals by selectively enriching these multivalent cations in the catholyte. In the second step, vanadium, molybdenum, and tungsten are separated from one another by adjusting the feed pH in the range of two to six to control the speciation of these metals. Our results demonstrate for the first time the utility of speciation control for selective ion separations by deionization shock waves.