Role of Physicochemical Aspects of Fibrous Particles in
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Transcript of Role of Physicochemical Aspects of Fibrous Particles in
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
Goal-ObjectiveGoal-ObjectiveGoal Develop scientific understanding on rheology of concentrated
mineral suspension - - PParticles of varying physicochemical propertiesarticles 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
Impact
Paints PetroleumMineral
Processing
Cosmetics
Food IndustriesDesired properties of suspensions•Higher solids content, • Varying morphology
Coarse /Fibrous particles,
• Low yield stress and viscosity, • Static and dynamic stability.
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http://readyfiber.com
Cement
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industry.usca9425.htmlhttp://www.rexart.com/
Materials and MethodsSpiking Experiment:
Examine rheological property of the pulp
Fibrous particles
Flotation
Rheological characterization
Yield Stress
Grind
Coarse particles - Copper Ore Fibrous particles – High Fiber Ore (Fibrous minerals )
Fibrous particles – Nylon Fibers
Chemically Inert
Coarse particles
Ore mixture
Spiking Experiments: Copper Ore mixed with Fibrous Ore in varying amountsSpiking Experiments: Copper Ore mixed with Fibrous Ore in varying amounts
Rheological behavior is affected with fibrous minerals in the suspension
Video on Pulp Rheology
•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
Network Formation by Fibrous Particles in Suspension
SEM of pulp – Copper ore +Fibrous oreSEM of dry fibers in Fibrous ore
SEM of fibers (fibrous ore ), taken from suspension
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
Effect of Particle size (Aspect ratio [AR]) on Rheology of Suspension
Rheological properties of suspensions are significantly affected with particle size (fiber length)
Aspect ratio = .027
Aspect ratio = 0.0015
Video on Pulp Rheology
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
Future plans• 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
AcknowledgementsCytec Industries,
Inc.Vale Inco