Preparation of Ti-enriched slag from V-bearing titanomagnetite by two-stage hydrochloric acid leaching route

• We report a novel process for preparing Ti-enriched slag from low-grade V–Ti concentrate.
• Macro impurities in the V–Ti concentrate were removed by dilute HCl leaching.
• M3O5 structure in V–Ti concentrate can be destroyed by homogeneous pressure leaching.
• The content of TiO2 in the Ti-enriched slag prepared can reach 92.5% with further removal of residual carbon.

Low-grade, highly reactive V–Ti concentrate was obtained from V-bearing titanomagnetite via selective reduction–magnetic separation. The main phases of the concentrate are anosovite and pyroxene. Two-stage acid leaching was employed to remove the impurities in the concentrate. The leaching behavior of impurities Ca/Mg/Al/Si under different acid leaching conditions in the first stage was investigated in detail. The optimal leaching conditions of the first-stage were as follows: 383 K leaching temperature, 1.40 mol/L HCl concentration, 1/10 solid–liquid mass ratio, and 120 min leaching time, under which the residue obtained contained 79.54% of TiO2 and 2.50% of V2O5. The result of molecular structure simulation indicate that the Ti–O and Mg–O bonds in the anosovite phase are broken under oxygen pressure conditions in the second stage by reacted with HCl solution. The content of TiO2 in the Ti-enriched slag prepared by two-stage acid leaching can reach 92.5% with further removal of residual carbon.