搅拌方式对多级钒页岩浸出槽内多相流行为的影响

Effect of Stirring Mode on Multiphase Flow Behaviors in Multistage Vanadium Shale Leaching Tank

钒页岩湿法提钒是一个多级浸出过程,现有的研究多将浸出槽视为单一的封闭容器,与现实情况不符,且作为新工艺的吹气搅拌机理和效果未有详细报道。采用数值模拟的方法,对比分析有无进出料口搅拌槽内流场与相分布,并研究搅拌方式对有进出料口搅拌槽内的多相流动行为的影响。结果表明:有无进出料口的搅拌浸出槽内流场有明显区别,同等机械搅拌条件下,有进出料口的近自由液面区域的死区由3.3%降低至1.8%,底部的死区则由1.07%降低至0.46%。当搅拌方式由仅吹气搅拌改变至仅机械搅拌时,顶层搅拌桨上部的区域流速由0.16 m/s增大至0.28 m/s,近自由液面的死区由8.5%降低至1.8%,底部死区的比例由2.68%降低至0.46%。而采用机械和吹气联合搅拌时,反而可能会削弱钒页岩的悬浮效果。

The wet extraction of vanadium from vanadium shale is a multi-stage leaching process.The existing research mostly regards the leaching tank as a single closed container,which is inconsistent with the reality,and the mechanism and effect of gas blowing stirring as a new process have not been reported in detail.The flow field and phase distribution in the stirred tank with inlet and outlet were compared and analyzed by numerical simulation,and the influence of stirring mode on multiphase flow behavior in leaching tank with inlet and outlet was studied.The results show that the flow field in stirred leaching tank with or without inlet and outlet is obviously different.Under the same mechanical stirring conditions,the dead zone in the near free surface area with inlet and outlet is reduced from 3.3%to 1.8%,and the dead zone at the bottom is reduced from 1.07%to 0.46%.When the stirring mode is changed from only blowing stirring to only mechanical stirring,the flow velocity in the upper part of the top impeller rises from 0.16 m/s to 0.28 m/s,the dead zone near the free surface drops from 8.5%to 1.8%,and the proportion of the bottom dead zone drops from 2.68%to 0.46%.On the contrary,when the mechanical and gas combined stirring is used,it will affect the suspension effect of vanadium shale.