Rapid Vanadium Extraction from Roasted Vanadium Steel Slag via a H2SO4-H2O2 System: Process and Mechanism.

Abstract

A H2SO4–H2O2 system was developed to enhance the efficacy of vanadium extraction from roasted vanadium steel slag. The optimum parameters and the behavior of vanadium extraction were investigated systematically. When 1 mL of H2O2 per gram of vanadium slag was added to a leaching mixture at 50 °C, along with 30% H2SO4, 80.5% of vanadium extraction was achieved within 15 min. However, without H2O2, only 58.5% of vanadium extraction was achieved at the same leaching time. The H2SO4–H2O2 system facilitated the dissolution of metallic ions in a short time and then triggered the production of strong oxidizing substances, such as HO• and O2–•, via the Fenton reaction and Fenton-like reaction. Subsequently, the low-valence vanadium, existing in the leaching solution or located on the surface of the particle, was converted to pentavalent vanadium by strongly oxidizing substances, such as H2O2 and its derivatives HO• and O2. The complex oxides on the surface of the particle were destroyed, after which the vanadium inside the particle was gradually exposed to the acid leaching solution. The vanadium was oxidized to pentavalent vanadium, which then entered the leaching solution. Finally, a pathway of vanadium extraction via the H2SO4–H2O2 system was proposed to gain insight into rapid vanadium leaching.