Abstract: A method to recycle the potassium in the potassium orthovanadate salt produced in sub-molten salt treatment of vanadium slag was proposed, and calcium oxide taken as an effective reagent to provide calcium ion, replacing the potassium in the salt. Potassium vanadate calcification conditions were systematically investigated, and the optimal operation parameters influencing the calcification efficiency obtained. By controlling the KOH concentration at 140 g/L, CaO excessive coefficient 1.2, and reaction temperature 90℃, 95.9% of potassium vanadate was calcified in 2 h, leading to formation of Ca10V6O25 precipitate, which could be used in production of steel alloying material ferrovanadium directly. And the potassium could be recycled in the form of potassium hydroxide, which was the major component for the vanadium slag decomposition using sub-molten salt media.

Key words: sub-molten salt, vanadium slag, potassium orthovanadate, calcification, cleaner production

摘要： 针对钾系亚熔盐法分解钒渣的中间产品钒酸钾，提出通过添加CaO实现钒酸钾中钾、钒分离，并同步实现钾再生循环的新方法，考察了各工艺参数对钙化沉钒的影响，得到钙化沉钒的最佳工艺条件. 结果表明，在KOH浓度140 g/L及CaO添加量为理论计算量的1.2倍、反应温度90℃、反应时间2 h的最佳工艺条件下，钒酸钾中钒转化率达95.9%以上，生成的钙化产物为Ca10V6O25，可直接用于钒铁冶炼，钾生成KOH返回用于分解钒渣.

关键词: 亚熔盐, 钒渣, 钒酸钾, 钙化沉钒, 清洁生产