1. Role of Physicochemical Aspects of Fibrous Particles in
Suspension Rheology and Mineral Beneficiation
P. Patra
Columbia University,
Cytec Industries.
Center for Particulate & Surfactant Systems (CPaSS)
IAB Meeting
New York City, N.Y.
August 2009

2. Goal-Objective Goal Objective
Develop scientific understanding on rheology of concentrated mineral suspension
- Particles of varying physicochemical properties
Objective
Determine contributions of
Physical factors
Morphology, Rugosity, Particle size
Entanglement of fibers – Network formation and hydrodynamics
Chemical factors
Strength of network:
Electrostatic, chemical interaction and hydrophobic interaction

3. www. petroleum-industry.usca9425.html
Impact
Desired properties of suspensions
Higher solids content,
Varying morphology
Coarse /Fibrous particles,
Low yield stress and viscosity,
Static and dynamic stability.
Food Industries
Cosmetics
Mineral
Processing
Paints
Petroleum
Cement
www. petroleum-industry.usca9425.html

4. Materials and Methods Spiking Experiment:
Examine rheological property of the pulp
Coarse particles
Fibrous particles – Nylon Fibers
Flotation
Grind
Ore mixture
Rheological characterization
Yield Stress
Chemically Inert
Fibrous particles
Fibrous particles – High Fiber Ore (Fibrous minerals )
Coarse particles - Copper Ore

5. Spiking Experiments: Copper Ore mixed with Fibrous Ore in varying amounts
Video on Pulp Rheology
Rheological behavior is affected with fibrous minerals in the suspension

6. Network Formation by Fibrous Particles in Suspension
SEM of dry fibers in Fibrous ore
SEM of pulp – Copper ore +Fibrous ore
Fibrous minerals form a strong network due to
multiple contact among fibers -
entanglement
Network causes
the rheological properties
inferior dispersion of particle s and air bubbles
reagents-mineral interactions
bubble-mineral interactions
SEM of fibers (fibrous ore ), taken from suspension

7. Correlation of Rheological Properties to the Processing Efficiency
Rheological properties of pulp is affected if it contains particles of fibrous morphology
Processing efficiency is significantly affected by the rheological properties of suspension
Reagents can negate the chemical factors contributing to rheology

8. Effect of Particle size (Aspect ratio [AR]) on Rheology of Suspension
Video on Pulp Rheology
Aspect ratio =
Rheological properties of suspensions are significantly affected with particle size (fiber length)

9. Summary and Conclusions
Rheological properties of suspension
Severely affected by Fibrous morphology – even at small concentrations of fibrous particles
Dependent on
Length of the Fiber
Diameter/thickness of the Fiber
Strength of network formation by fibrous particles
Processing efficiency can be improved
Addition of chemical reagents
Can improve rheology of mineral suspension

10. Future plans Acknowledgements Cytec Industries, Inc. Vale Inco
Additional physicochemical aspects to be studied
Surface chemical properties
Rugosity of particles
Particle-particle and particle-reagent interactions
Rheological model to relate experimental results
Conduct fundamental and applied studies
Conduct solution chemistry studies to determine species responsible for adverse affect on rheology and separation efficiency
Correlate rheological results to the selective separation of valuable minerals
Acknowledgements
Cytec Industries, Inc.
Vale Inco