Sep. Purif. Technol.

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. (C) 2014 Elsevier B.V. All rights reserved.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. (C) 2014 Elsevier B.V. All rights reserved