Efficient Separation of Silicon and Vanadium by Sodium Roasting-Water Leaching from Vanadium Slag and CaV2O6 Preparation

Calcium vanadate (CaV2O6), a new product of vanadium precipitation, was obtained from slag by sodium roasting-water leaching and calcium precipitation. The separation behavior silicon in during roasting water systematically studied, micro-morphology valence migration Fe slag, residue were revealed. Na2CO3 added to the at 20% mass fraction, roasted 790 °C, kept for 120 min, sample deionized aqueous solution with liquid-solid ratio (L/S) 5mL/g, then heated 90 °C 60 89.54% 1.96% chromium extracted. Sodium carbonate tends combine form vanadate, while is easy Na acmite (NaFeSi2O6). When molar N (Ca/V) 0.6 CaO, adjust pH 6.7 ± 0.1 precipitate min precipitated CaV2O6 purity 95.69%, under these conditions, precipitation 95.03%.