An Ammonium-Free Vanadium Precipitation Strategy for the Preparation of High-Purity V2o5: Enhancing Vanadium Purification in High-Acid Solutions Via Mextral 984h Extraction and H2o2 Stripping

Abstract

This research introduces an innovative closed–loop purification method for the treatment of highly acidic vanadium-containing solutions, specifically addressing the two major challenges in the vanadium slag salt-free roasting and ammonium-free vanadium precipitation processes. These challenges are the selective extraction and separation of vanadium from a multi-element solution containing Mn, Fe, Ca, K, Na, Si, Al, and P under highly acidic conditions (pH = 0.16), and the efficient stripping of vanadium using hydrogen peroxide in a chelating extraction system. Under the optimized conditions, the single-stage extraction efficiency reached 90.47%, whereas three-stage countercurrent extraction reduced the residual vanadium concentration in the solution to <0.02 g/L. In the stripping stage, the single-stage stripping efficiency was 74.57%, while two-stage cross-flow stripping achieved a recovery of 99.40%. Subsequently, V2O5·nH2O was synthesized via the high-temperature water bath method and then calcined at 450 °C for 2 h to promote conversion into V2O5. Notably, the purity of the final V2O5 product exceeded 99.23%. Overall, this study characterizes the ionic forms of vanadium under highly acidic conditions, reveals the chelating extraction and stripping mechanisms of vanadium, and establishes a solid theoretical foundation for the advancement and application of a clean process involving salt-free roasting of vanadium slag and ammonium-free vanadium precipitation.

Keywords: Extraction, Stripping, Ammonium-free vanadium precipitation, Zero emission, Clean vanadium extraction