Recovery of vanadium from spent catalysts and alumina residues

Abstract

The various process options available to recover vanadium from spent dehydrosulphurisation catalysts, sulphuric acid catalysts, and alumina sludge residues from the Bayer Process are reviewed, and the fate of other metal impurities such as Mo, Ni, Co, Al and Fe are considered. Most processes give an impure V2O5 product, but selective solvent extraction of vanadium from the impure leach solution allows high purity product to be obtained. A comparison is made between the D2EHPA and Amine extractants with regard to the vanadium species and other metals extracted. The results of studies with tertiary and quaternary amines in acidic media are reported, and the relative performance of quaternary amines in extracting a range of vanadium(V) anionic species between pH 6–13 is presented. It is shown that quaternary amines offer the greatest flexibility for treating acidic, neutral, or alkaline liquors depending on the process of choice.