Extraction and separation of vanadium from high-acidity stone coal leaching solution using N235 coupling with hydrogen peroxide

• A novel H 2 O 2 –N235 system enabled efficient vanadium extraction from high-acidity leachate by forming peroxovanadates for selective anion exchange.. • Single-stage vanadium extraction efficiency reached 96.99% under optimized conditions, with minimal co-extraction of impurities. • Sulfuric acid–ascorbic acid system effectively stripped vanadium, producing a high-purity vanadium-enriched solution (19.94 g/L). • Mechanistic analysis revealed that vanadium peroxocomplexes were selectively extracted via anion exchange by protonated trialkylamine. • The process was validated at pilot scale, demonstrating industrial feasibility and sustainability. To enhance the efficiency of vanadium extraction and separation from high-acidity stone coal acid leach solution, a novel method based on hydrogen peroxide oxidation and coordination of vanadium ions was proposed in this study. Vanadium was effectively extracted from the high-acidity stone coal leaching solution through a synergistic process involving H₂O₂ oxidation coupled with trialkylamine (N235) extraction. The results indicated that the single-stage vanadium extraction efficiency reached 96.99% under optimal conditions, using 30% N235 (v/v) and 70% sulfonated kerosene as the organic phase, with an initial acidity of 1.5 mol/L, an organic/aqueous phase ratio (O/A) of 2:1, a temperature of 30°C, and an extraction time of 20 min. The V-loaded organic phase was effectively stripped by a mixed solution of sulfuric acid-ascorbic acid. the content of V in the stripping aqueous solution reached up to 19.94g/L, while impurities (Fe, Al, Mn, Si, and Ca) remained below 0.05 g/L. The mechanism of vanadium extraction using the H₂O₂–N235 synergistic system was investigated through slope analysis, saturation extraction experiments, Raman spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and quantum chemical calculations. Results confirmed that under the oxidation and coordination action of H₂O₂, vanadium ions were converted from VO 2+ cation into stable peroxovanadate anion VO(O 2 )- 2, which were subsequently extracted into the organic phase via an anion-exchange mechanism, forming [VO(O 2 ) 2 (R 3 NH)] complexes. This study addresses the challenges of vanadium extraction from high-acidity stone coal acid leach solution, providing valuable insights for vanadium recovery in industrial applications.