Flow Field Study of Sodium Aluminate Solution Slurry in an Unagitated Precipitation Tank by CFD Simulation

In order to explore the feasibility of remove agitation in gibbsite precipitation process, computational fluid dynamics method was carried out to study the flow field of sodium aluminate solution slurry in an unagitated precipitation tank. The solid content distribution is investigated by volume fraction of solid phase. The simulation results showed that little difference of solid content is found in the range between the tank bottom and the height position of 25 meters, which is the most zone of the tank, and there is a somewhat large difference in the top 5 meters zone, where the stratification occurs. With the inlet velocity increases, the zone of stratification shrinks to near the tank surface, which makes the solid content distribution in the whole tank seem uniform much more. Therefore, without agitation, the solid content would not concentrate to tank bottom completely in the normal work flow.

[1]  Shaona Wang,et al.  Improved precipitation of gibbsite from sodium aluminate solution by adding methanol , 2009 .

[2]  S. Veesler,et al.  Agglomeration of gibbsite Al(OH)3 crystals in Bayer liquors. Influence of the process parameters , 1998 .

[3]  Bülent Karasözen,et al.  Numerical method for optimizing stirrer configurations , 2005, Comput. Chem. Eng..

[4]  B. K. Mishra,et al.  Precipitation of boehmite in sodium aluminate liquor , 2009 .

[5]  Jie-min Zhou,et al.  Experimental verification of mathematical model for multiphase flow in air-agitated seed precipitation tank , 2011 .

[6]  Efstathios E. Michaelides,et al.  Effect of the history term on the motion of rigid spheres in a viscous fluid , 1994 .

[7]  I. Livk,et al.  Supersaturation and temperature dependency of gibbsite growth in laminar and turbulent flows , 2003 .

[8]  B. Tripathy,et al.  Effect of temperature and alumina/caustic ratio on precipitation of boehmite in synthetic sodium aluminate liquor , 2007 .

[9]  Yifei Zhang,et al.  Experimental investigation and CFD simulation of liquid–solid–solid dispersion in a stirred reactor , 2010 .

[10]  J. Joshi,et al.  CFD simulations of gas-liquid-solid stirred reactor: prediction of critical impeller speed for solid suspension , 2007 .

[11]  Mattias Ljungqvist,et al.  Numerical Simulation of the Two-Phase Flow in an Axially Stirred Vessel , 2001 .

[12]  Vivek V. Ranade,et al.  Numerical simulation of dispersed gas-liquid flows , 1992 .

[13]  A. S. Noskov,et al.  Solid dispersion in the slurry reactor with multiple impellers , 2011 .

[14]  Fernando J. Muzzio,et al.  Mixing analysis in a tank stirred with Ekato Intermig® impellers , 2004 .