矿浆电解槽内固液搅拌对隔膜变形的影响

Effect of solid-liquid stirring on membrane deformation in the slurry electrolysis tank

  • 摘要: 矿浆电解作为一种短流程湿法冶金工艺,隔膜袋在搅拌桨搅动及矿石的磨损下会产生变形,甚至出现破裂,严重制约了生产效率。针对该问题,基于单向流固耦合原理,采用计算流体力学与固体有限元相结合的方法对矿浆电解搅拌槽内隔膜变形规律进行了全三维解析。研究发现隔膜袋两侧压差是导致变形的根本原因,最大变形量出现在垂直高度y=1.2 m位置处,且搅拌转速越大,隔膜变形所需的最佳液位差越小。当阴极区压力不足时,隔膜袋向内挤压变形;压力增加后,则向两侧鼓包。隔膜最大变形量随流体域固体体积含量(SL)的增加先减小后增加,在SL=15%时,隔膜变形达到最小值226.7 mm;越靠近槽下部,SL对绝对压力的影响越大。添加框架约束后,隔膜最大变形量减小到0.664 mm。通过可视化的解析,可以为矿浆电解工业控制提供参照。

     

    Abstract: As a short-process hydrometallurgical technology, slurry electrolysis (SE) collects the stirring that improves the suspension of ore, the membrane bag that acts as purifying, and the cathodic and anodic plates that promote ion migration in one tank. The stirring helps to maintain the ore suspended. As the SE tank is stirred, the membrane bag will deform and become damaged, severely limiting production efficiency. In this research, the one-way fluid-structure interaction (FSI) was used to examine the impact of the solid–liquid suspension on membrane deformation, which was based on the computational fluid dynamics (CFD) and solid finite element method (FEM). Through the full 3D quantitative analysis, the database of membrane deformation under various conditions was established. The membrane was extruded to the center during the initial stirring conditions, and the greatest deformation measured 891.66 mm. Primarily, membrane deformation was brought on by the pressure differential brought on by liquid velocity, solid concentration distribution, and liquid level. The maximum deformation of the membrane first decreased and then increased with the increased liquid level difference between the cathode and anode. With the upper fixed constraint, the maximum deformation of the membrane appears at y = 1.2 m. The larger the stirring speed is, the smaller the optimal liquid level difference required to minimize the membrane deformation. The stirring speed changes the overall pressure distribution by changing the dynamic pressure in the anode domain. The maximum deformation of the membrane decreases first and then increases with the increase of electrolyte density in the cathode domain. The membrane bag is extruded to the cathode domain when the pressure in the cathode region is insufficient because of the low electrolyte density in the cathode domain. When the cathode pressure increases, the membrane bag bulges to both sides, and the inner bulge is greater than the outer. With an increase in solid volume concentration (SL) in the anode domain, the maximum membrane deformation first reduces and subsequently increases. When SL = 15%, the membrane deformation reaches the minimum value of 226.7 mm. The closer to the bottom of the tank, the greater the influence of solid content on absolute pressure. The maximum membrane deformation is drastically decreased to 0.664 mm when the frame restrictions are considered. It can support the industrial control process via visual analysis.

     

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