SE 2: Fundamentals of Liquid Liquid Extraction
     Part 1: Introduction
         1. FUNDAMENTALS OF SOLVENT EXTRACTION
     Part 2: Mass transfer with Chemical Reaction
         1. INTRODUCTION
             1.1 General
             1.2 The Site of Reaction
             1.3 The data used for MTCR work
             1.4 Concentrations to be used in modelling
             1.5 Difficulties encountered in MTCR measurements
             1.6 Approaches to modelling MTCR
                 1.6.1 The main theories
             1.7 Modelling MTCR with competing solutes and competing extractants
             1.8 Conclusion
             1.9 REFERENCES TO CHAPTER 1
         2. METHODS OF STUDYING MASS TRANSFER RATES IN LIQUID-LIQUID SYSTEMS
             2.1 INTRODUCTION
             2.2 A review of Contacting Devices
                 2.2.1 Constant Interface Cells
                 2.2.2 Methods involving drops
                 2.2.3 Other Methods
             2.3 Analysis of concentrations
             2.4 Conclusions
             2.5 REFERENCES TO CHAPTER 2
         3. FUNDAMENTALS
             3.1 Molecular diffusion
             3.2 Eddy diffusion
             3.3 Mass transfer coefficients
             3.4 Mass transfer to the interface
                 3.4.1 Film theory
                 3.4.2 Penetration theory
                 3.4.3 Penetration with surface renewal
             3.5 Mass transfer across the interphase region
             3.6 Mass transfer with chemical reaction
                 3.6.1 Diffusion, reaction and residence time
                 3.6.2 Diffusion and reaction driving forces
                 3.6.3 Rate controlling mechanism of transfer
             3.7 Diffusional mass transfer involving drops
                 3.7.1 Mass transfer to the drops
                 3.7.2 Mass transfer inside the drop
                 3.7.3 Effective diffusivity
             3.8 Mass transfer during drop formation
                 3.8.1 Interfacial area and mass transfer coefficient
                 3.8.2 Evaluation of experimental data
                 3.8.3 Diffusion models for mass transfer during drop formation without circulation
                 3.8.4 Diffusion models for mass transfer during drop formation with circulation
             3.9 Drop swarms
                 3.9.1 Relative change in drop concentration for variable continuous phase concentration
             3.10 Enhanced mass transfer
                 3.10.1 The Marangoni effect
                 3.10.2 Electric field effects
                 3.10.3 Chemical Synergists
             3.11 Use of Maxwell-Stefan equations - computer modelling
             3.12 Conclusion
             3.13 REFERENCES TO CHAPTER 3
         4. APPLICATIONS
             4.1 INTRODUCTION
             4.2 ORGANICS
                 4.2.1 Introduction
                 4.2.2 Hydrolysis of organic substances
                 4.2.3 Alkylation of Aromatic Substances
                 4.2.4 Nitration of Aromatics
                 4.2.5 Sulphonation of Aromatic Hydrocarbons
             4.3 ACIDS
                 4.3.1 Introduction
                 4.3.2 Extraction of mineral acids
                 4.3.3 Organic acids
             4.4 METALS
                 4.4.1 Introduction
                 4.4.2 Uranium/plutonium/nitric acid
                 4.4.3 Other nuclear application
                 4.4.4 Transition metals
                 4.4.5 Other metals
             4.5 Conclusion
             4.6 REFERENCES TO CHAPTER 4
         5. NOTATION
     Part 3: Surface Phemonena in Solvent Extraction Processes
         1. INTRODUCTION
         2. INTERFACES
             2.1 Introduction
             2.2 Theories of the Interfacial Tensions
                 2.2.1 Surface tension
                 2.2.2 Interfacial tension
                 2.2.3 Surface pressure
             2.3 Thermodynamics of the Interface
             2.4 Charged Interfaces
                 2.4.1 Interffacial potentials
                 2.4.2 The diffuse double layer
                 2.4.3 Surface pH related to Interface potential and zeta potential
             2.5 The Distances Involved in the Interfacial Region and in Monolayers
         3. EXPERIMENTAL TECHNIQUES
             3.1 Preparing to Measure
                 3.1.1 Cleaning techniques
                 3.1.2 Water preparation
                 3.1.3 General chemicals
                 3.1.4 Standard monolayer-forming amphiphiles
                 3.1.5 Extractant molecules
                 3.1.6 Preparing the solutions and surface for experiment
             3.2 The Measurement of Interfacial Tension
                 3.2.1 Interfacial tensions at equilibrium
                 3.2.2 Techniques for dynamic interfacial tensions
                 3.2.3 Possibilities for the continuous measurements of interfacial tensions
             3.3 Surface Pressure p and the Langmuir Trough
             3.4 Measurement of Surface and Interfacial Potentials D V and the Zeta Potential
                 3.4.1 The surface potential
                 3.4.2 The zeta potential
             3.5 The Measurement of Surface Viscosity, h s.
                 3.5.1 The canal method
                 3.5.2 The rotational torsional method
                 3.5.3 Other methods
             3.6 Some Values of Interface Potentials for Systems of Interest in Solvent Extraction
                 3.6.1 Systems involving organic solutes
                 3.6.2 Systems involving metal extractants
             3.7 Equations for the Prediction of Interface Potential
                 3.7.1 Antonoffs rule
                 3.7.2 Intermolecular force equations
                 3.7.3 Equations based on local composition
         4. ADSORPTION AND INTERFACES
             4.1 Possibilities for Measurement of the Adsorption
             4.2 Adsorption Equations
                 4.2.1 The Gibbs equation
                 4.2.2 The surface equations of state
                 4.2.3 Other adsorption isotherms
             4.3 Orientation of Molecules at Interfaces
             4.4 Vicinal Water
             4.5 Amphiphiles of Importance to Solvent Extraction
                 4.5.1 Molecular type
                 4.5.2 Micelles
             4.6 Reaction and Diffusion Involving Monolayers
                 4.6.1 Reactions at monolayers
                 4.6.2 Rates of diffusion of molecules at the interface
                 4.6.3 Rates of diffusion of molecules across an interface
             4.7 The Effects of Electric Fields on Liquid-Liquid Interfaces
                 4.7.1 Imposed charge due to adsorption of ions alone
                 4.7.2 Imposed external voltage - low fields
                 4.7.3 Imposed external voltage - high fields
         5. SPONTANEOUS INTERFACIAL CONVECTION - THE MARANGONI EFFECT
             5.1 Introduction
             5.2 The Cause of the Marangoni Effects
                 5.2.1 Instabilities in general
                 5.2.2 Mass transfer driven instabilities
                 5.2.3 Temperature driven instabilities
             5.3 The Criteria for Marangoni Instability
                 5.3.1 General criteria for simple systems - mass and heat transfer
                 5.3.2 Systems Involving chemical reactions and sorption at the Interface
                 5.3.3 Systems resulting from electrical or electrochemical constraints
             5.4 Quantitative Analysis of Instabilities
         6. INTERFACIAL PROPERTIES OF EXTRACTANTS
             6.1 An Order of Interfacial Activity
             6.2 Attempts to Relate Extractant Structure to Surface Activity
             6.3 Results for Specific Extractants
                 6.3.1 Hydroxyoximes
                 6.3.2 b -diketones
                 6.3.3 Organophosphorus acids
         7. EFFECTS OF INTERFACIAL PHENOMENA ON MASS TRANSFER IN LIQUID-LIQUID SYSTEMS
             7.1 Introduction
             7.2 Mass Transfer in Liquid-Liquid Systems in the Absence of Interfacial Turbulence
                 7.2.1 A new technique
                 7.2.2 The site of reaction
                 7.2.3 Modelling the mass transfer rates
             7.3 Mass Transfer in Liquid-Liquid Systems in the Presence of Interfacial Turbulence
             7.4 Mass Transfer in the Presence of Micelles
             7.5 Barriers to Mass Transfer at Interfaces
                 7.5.1 Physical barriers
                 7.5.2 Chemical barriers
         8. WETTING AND ADHESION
             8.1 Introduction
             8.2 The Basic Physical Chemistry of Wetting
                 8.2.1 Contact angles and wetting
                 8.2.2 Some basic equations
                 8.2.3 The critical surface tension
                 8.2.4 Real surfaces
             8.3 Practical Consequence of Wetting
                 8.3.1 "Crud"
                 8.3.2 The wetting of Internals of coalescers and contactors
         9. LIQUID DROPS, DISPERSIONS AND EMULSIONS
             9.1 Introduction
             9.2 Discrete Drop Behaviour
                 9.2.1 Drop formation
                 9.2.2 Drop motion
                 9.2.3 Drop velocity
             9.3 Drop Sizes in Dispersions
             9.4 Methods for Drop Size Measurement in Dispersions
                 9.4.1 Macrophotography
                 9.4.2 Light transmission
                 9.4.3 Particle size measurement devices
                 9.4.4 Capillary withdrawal methods
                 9.4.5 Viscometry
             9.5 Double Dispersions
             9.6 Mass Transfer to Single Drops
                 9.6.1 General features
                 9.6.2 Effects of surface active chemicals on mass transfer rates
             9.7 Coalescence
             9.8 Emulsions
                 9.8.1 Introduction
                 9.8.2 The role of the emulsfier
                 9.8.3 Classification of chemical emulsifiers
                 9.8.4 Types of chemical emulsffier
                 9.8.5 Methods for making emulsions
                 9.8.6 Stability and breakdown
         10. PHASE INVERSION
             10.1 Introduction
             10.2 The Phase Diagram for Inversion
             10.3 Volume Fractions and Phase Inversions
             10.4 Theories of Phase Inversion
         11. IMPLICATIONS OF SURFACE EFFECTS FOR LIQUID-LIQUID EXTRACTION PROCESSES AND EQUIPMENT OPERATION
             11.1 Time Dependent Effects
             11.2 Structure of Solvent Molecules - Emulsification Solubility Loss and Extraction Rate
                 11.2.1 Emulsification
                 11.2.2 Solubility loss
                 11.2.3 Extraction rate
             11.3 Wetting of Internals and Maintenance of the Desired Dispersion
             11.4 'Crud'and Entrainment Problems
             11.5 Liquid-Liquid Extraction Plant Operations and Impurity Transfers
                 11.5.1 Up-stream and down-stream processing
                 11.5.2 Surfactant addition from fire-fighting foam
         12. CONCLUSIONS AND RECOMMENDATIONS
             12.1 Conclusions
             12.2 Recommendations
         13. REFERENCES
         14. NOMENCLATURE

Part 1 Introduction
Part 2 Mass transfer with chemical reaction in liquid-liquid systems
Part 3 Surface phenomena in solvent extraction processes

 

 

Volume SE II   Part 1 Introduction.

This part gives an overview of the volume and how to use it to best effect.

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Volume SE II   Part 2 Mass transfer with chemical reaction in liquid-liquid systems.

Examples of heterogeneous reactions, in which mass transfer occurs to and from interfacially localised reaction zones, are common in liquid-liquid systems of industrial interest. The basic kinetic steps of diffusion and chemical reaction are described together with the theories adduced to describe them and their effect on overall rate. This is followed by a description of laboratory equipment in which mass transfer/reaction systems can be studied under conditions of well-characterised interfacial area and flow regime. The interaction of mass transfer and reaction is next described in relation to industrial extractions, including aromatic nitration, sulphonation alkaline hydrolysis, alkylation of organic compounds and metal extraction by acidic, basic and solvating reagents. Also considered are the two key factors, the site of chemical reaction and the kinetic regime, with particular reference to their effect on the overall process and on equipment selection. In conclusion, the importance to industrial equipment design of a very thorough and systematic understanding of kinetics and reaction site, and the hydrodynamics of the laboratory and industrial equipment, is reiterated.

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Volume SE II   Part 3 Surface phenomena in solvent extraction processes.

The importance of phase boundary effects in liquid-liquid extraction has long been recognised and of particular importance is the liquid-liquid boundary itself, since the required mass transfer occurs across this interface. The chemical-physical nature of this interface is often closely related to the most important steps in the transfer process and may dictate the overall kinetics. The foundations of interfacial phenomena are reviewed including a discussion of surface properties at the interface and how they can be measured. A description is given of the current state of knowledge on adsorption at interfaces, the Marangoni effect, emulsions and phase inversion. The implications of these surface phenomena for extraction processes and equipment operation are discussed.