Related Experiment Videos
Batch gravitational sedimentation of slurries
1Chemical Engineering Department, National Taiwan University, Taipei, Taiwan.
Journal of Colloid and Interface Science
|November 18, 2005
Summary
This study used CATSCAN to analyze kaolin and ball clay slurry settling, revealing complex rheological behavior. Slurries initially act as plastic fluids but become elastic upon settling, with ball clay being more compressible.
Area of Science:
- Materials Science
- Chemical Engineering
- Rheology
Background:
- Understanding slurry settling is crucial for industrial processes.
- Previous models often assume distinct elastic or plastic behaviors.
- The rheological properties of kaolin and ball clay slurries require detailed investigation.
Purpose of the Study:
- To investigate the batch settling behavior of kaolin and UK ball clay slurries.
- To monitor the spatio-temporal evolution of solids fractions during consolidation.
- To analyze the rheological characteristics (elastic vs. plastic) of the slurries.
Main Methods:
- Utilized a computerized axial tomography scanner (CATSCAN) for continuous monitoring.
- Investigated slurries at various initial solids fractions (phi(0)s).
- Employed an averaging procedure to estimate null-stress solids fractions (phi(g)s) due to blurred interfaces.
Main Results:
- Slurries exhibit complex rheological behavior, neither purely elastic nor purely plastic.
- High initial solids fraction slurries initially behave as plastic fluids, then transition to elastic solids.
- Ball clay slurry is more compressible than kaolin slurry; higher initial solids fraction leads to less compressible sediment.
Conclusions:
- The dynamic settling process reveals a transition from plastic to elastic behavior.
- Blurred supernatant-sediment interfaces complicate gel point determination in these slurries.
- Compressibility differs between kaolin and ball clay, influenced by initial solids concentration.