Abstract:Pilot experiments on Na₂SO₄-roasting of V-Ti magnetite (VTM) concentrate pellets were performed to activate vanadium with simulated grate-kiln machines. Combined with thermodynamic calculation, X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and inductively coupled plasma-atomic emission spectrometry (ICP-AES) analyses, process parameters of pellet making were optimized, and the enhancement of vanadium oxidation and conversion was realized. The results show that, in balling stage, adding Na₂SO₄ can promote the thermal decrepitation resistance of green pellets; in the drying stage, higher wind temperature can improve the dispersion of sodium salt in pellets; in preheating stage, using O₂-rich hot gas can promote more thorough oxidation of vanadium; in roasting stage, the effect of vanadium conversion to sodium vanadate is better when the liquid amount is 15.5%-22.5%. Based on the above measures, the vanadium conversion rate achieved in the roasted pellets is 85.6%, proving the feasibility of vanadium recovery using an existing pellet production line.

Key words: vanadium; V-Ti magnetite pellet; Na₂SO₄ roasting; grate-kiln process; thermodynamics