Investigation of Acid Leaching of Vanadium Slag under the Atmospheric Pressure

This is a paper in the field of metallurgical engineering. The vanadium slag of a steel plant in Chengde, Hebei Province was used as the object of study. In view of the production of toxic and harmful gases of the current process of "sodium roasting-vanadium extractionby water leaching" of vanadium slag, low recovery of vanadium and the failure of comprehensive utilization of valuable metals. Based on the thermodynamic study of Fe-V-H₂O system, the effects of grinding fineness, reaction temperature, sulfuric acid concentration, liquid-solid ratio, leaching reaction time and stirring speed on vanadium slag leaching were investigated under atmospheric condition. The results show that leaching temperature, sulfuric acid concentration and liquid-solid ratio have significant effects on vanadium slag leaching. Under the conditions of particle size of D₉₅ for 16 μm, reaction temperature for 90 ℃, liquid-solid ratio for 8∶1, concentration of H₂SO₄ for 4 mol/L, leaching time for 8 h and stirring speed for 400 r·min^-1, vanadium leaching rate is 86.33%. The amorphous SiO₂ produced in the process of acid dissolution may cover the surface of incompletely dissolved mineral particles and hinder the further acid dissolution of them.