Table Of ContentHeat and Mass Transfer
Series Editors: D. Mewes and F. Mayinger
Springer-Verlag Berlin Heidelberg GmbH
ONLINE LIBRARY
Engineering
http://www.springer.de/engine/
Hans-Jo rg Bart
Reactive Extraction
With 101 Figures
Springer
Series Editors
Prof. Dr.-lng. Dieter Mewes Prof. Dr.-lng. E. h. Franz Mayinger
Universitat Hannover Technische Universitat Miinchen
lnstitut fiir Verfahrenstechnik Lehrstuhl A fur Thermodynamik
CallinstraBe 36 BoltzmannstraBe 15
30167 Hannover, Germany 85748 Garching, Germany
Author
Prof. Dipl.-lng. Dr. Hans-Jo rg Bart
Universitat Kaiserslautern
FB Maschinenbau und Verfahrenstechnik
Lehrstuhl fur Thermische Verfahrenstechnik
Gottlieb-Daimler-StraBe
67663 Kaiserslautern, Germany
ISBN 978-3-642-07430-1
Library of Congress Cataloging-in-Publication Data applied for
Die deutsche Bibliothek - cIP-Einheitsaufnahme
Bart, Hans-Jorg:
Reactive extraction / Hans-Jorg Bart. -Berlin; Heidelberg; New York ; Barcelona; Hong Kong; London;
Milan; Paris; Singapore; Tokyo: Springer, 2001
(Heat and mass transfer)
(Engineering online library)
ISBN 978-3-642-07430-1 ISBN 978-3-662-04403-2 (eBook)
DOI 10.1007/978-3-662-04403-2
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Preface
This booklet is designed to bridge the gap between handbooks and technical
literature and aims at graduate students or experienced readers. Commercial
flow sheeting simulation software is increasingly available and is used in the
early steps of process design in industry. As to this, more sophisticated and
precise models based on activities instead of concentrations should be used.
After an introductory chapter there is in Chapter 2 an intensive discussion of
reactive phase equilibria of ionic and non-ionic solutes based on chemical
potentials. Chapter 3 introduces to multicomponent diffusion and mass
transfer. However, the main focus is on the reactive mass transfer on rigid and
mobile surfaces where the interfacial reaction, molecular diffusion and
adsorption layers are decisive. The respective extraction of zinc with a cation
exchanger and of acetic acid with an anion exchanger is discussed as case
studies. Since adsorption layers and surfactants have a major impact on
liquid-liquid extraction efficiency, the final chapter reviews several tech
niques which make use of polymeric species in an extractive process. A short
review is also given on extraction apparatus and the hydrodynamics (hydraulic
design, droplet populance balances) of columns.
Much of the booklet is based on the PhD works of C. Czapla (2000),
G. Modes (2000), H. Klocker (1996), T. Kronberger (1995), M. Marters
(2000), M. Roos (2000), M. Traving (2000) and B. Wachter (1996) who I
wish to thank for their fruitful contributions. I also appreciate the stimulating
discussions I have had with Dr. M.J. Slater (University of Bradford, Great
Britain) and Prof. J.A. Wesselingh (University of Groningen, The Nether
lands) which helped clarify my thinking and led me to new ways of presenting
some of the material. Special thanks go to my wife Ariane and my secretary
I. Behrendt for typing and retyping the drafts, to Prof. Dr. J. Draxler (Montan
universitat Leoben, Austria) for proof-reading the text and to my co-worker
D. Bosse who helped with the text, figures and final tedious layout of the
book.
Kaiserslautern, September 2000 Hans-Jorg Bart
Table of Contents
NOMENCLATURE ............................................................................................. IX
1 REACTIVE EXTRACTION ........................................................................ 1
1.1 INTRODUCTION .......................................................................................... 1
1.2 PHYSICAL EXTRACTION SYSTEMS ............................................................. 4
1.3 CHEMICAL EXTRACTION SYSTEMS .......................................................... 10
1.4 PROCESS DEVELOPMENT AND DESIGN ..................................................... 13
2 LIQUID-LIQUID PHASE EQUILIBRIA ................................................ 17
2.1 EQUILIBRIUM CONDITIONS ...................................................................... 17
2.2 NON-IONIC SYSTEMS ............................................................................... 21
2.2.1 The Regular Solution Theory ........................................................... 21
2.2.2 Solvatochromic Models .................................................................... 23
2.2.3 Margules Equation ........................................................................... 26
2.2.4 NRTL Model ..................................................................................... 27
2.2.5 UN1QUAC Model ............................................................................. 28
2.2.6 Group Contribution Methods ........................................................... 30
2.3 ELECTROLYTE SYSTEMS .......................................................................... 32
2.4 ION EXCHANGE EQUILIBRIA IN LIQUID-LIQUID SYSTEMS ...................... 37
2.4.1 Metal/Cation Exchange System ....................................................... 37
2.4.2 Acid/Anion Exchange System ........................................................... 47
3 REACTIVE MASS TRANSFER ............................................................... 51
3.1 INTRODUCTION ........................................................................................ 51
3.2 PHYSICAL MASS TRANSFER ..................................................................... 52
3.2.1 Fick's Law ........................................................................................ 52
3.2.2 The Maxwell-Stefan Law ................................................................. 55
3.2.3 Electrolyte Systems .......................................................................... 61
3.2.4 Bootstrap Relation ........................................................................... 65
3.2.5 Estimation of Diffusion Coefficients ................................................ 66
3.2.6 Mass Transfer .................................................................................. 74
3.3 REACTIVE EXTRACTION KINETICS ........................................................... 82
3.3.1 Suifactants, Zeta Potential and the Initial Reaction Rate ............... 82
3.3.2 Microkinetics ofZn-D2EHPA ......................................................... 90
3.3.3 Macrokinetics ofZn-D2EHPA ...................................................... 105
3.3.4 Microkinetics ofA cid Extraction with TOA ................................... 119
3.3.5 Macrokinetics ofA cid Extraction with TOA .................................. 128
VIII Table of Contents
4 CURRENT DEVELOPMENTS AND APPARATUS TECHNIQUES 131
4.1 LIQUID-LIQUID CONTACTING ............................................................... 131
4.2 POLYMERIC EXTRACTION SYSTEMS ...................................................... 140
APPENDIX A -CONVERSION FROM MOLAR TO MOLAL .................. 150
APPENDIX B -ACTIVITY COEFFICIENT CONVERSION ..................... 153
APPENDIX C -OPERATION AND DESIGN OF A SIEVE TRAY ........... 156
C.1 OPERATING AND DESIGN VARIABLES .................................................. 157
C.2 OPERATING LIMITS .............................................................................. 158
C.3 THE MANY VARIABLES ....................................................................... 159
CA BOUNDARIES OF THE OPERATING RANGE AND DESIGN VARIABLES ... 159
C.4.] Inactive Holes ................................................................................ 159
C4.2 Entrainment ................................................................................... 161
C4.3 Column Diameter .......................................................................... 162
C4.4 Height of the Coalescence Layer .................................................. 162
C4.5 Slip Velocity and Flooding ............................................................ 164
C.4.6 Tray Operation .............................................................................. 166
C4.7 Design a Sieve Tray ....................................................................... 168
APPENDIX D -THE LAP MODEL FOR MULTICOMPONENT
MIXTURES ................................................................................................ 172
APPENDIX E -PHYSICAL AND CHEMICAL PROPERTIES FOR
ZnID2EHPA AND HAclTOA .................................................................... 178
LITERATURE ................................................................................................... 183
AUTHOR INDEX .............................................................................................. 203
SUBJECT INDEX .............................................................................................. 207
Nomenclature
A Interfacial area [m']
A,R,C Margules parameter [-]
Area downcomer [m']
Area of holes [m2]
Tray area [m']
Debye-Htickel constant [m312morl12]
a Specific interfacial area [m2/m3]
a Ionic radius [m]
Activity of species i [-]
Activity of water [-]
Coefficient [-]
Function of the Maxwell-Stefan diffusion
coefficients and mol fractions of a mixture [s/m2]
Instability constant [-]
Constant [depends]
C C Kinetic constants [depends]
1, ••• , 4
C;;, Cu Density of energy of cohension [cal/cm3]
C¢ Pitzer parameter [-]
Solvatochromic parameter [-]
c, Molar density of species i [mol/L]
Molar density of solvent [mollL]
Molar mixture density [mollL]
Initial molar density [mollL]
Standard molarity (l mollL) [mollL]
D Distribution coefficient [-]
D Diameter [m]
D Fick's diffusion coefficient (binary) [m2/s]
D2EHPA Di(2-ethylhexyl) phosphoric acid
D. Fick's diffusion coefficient[m2/s]
'1
X Nomenclature
D,/
Diffusion coefficient at infinite dilution (x,---70) [m'/s]
D ~ Axial dispersion coefficient [m2/s]
Dk Column diameter [m]
[) Maxwell-Stefan diffusion coefficients (binary) [m2/s]
[)'j Maxwell-Stefan diffusion coefficients [m'/s]
DR Rotor diameter [m]
Ds Stator diameter [m]
d Droplet diameter [m-1]
d, Driving force for mass diffusion [m-']
ds Sauter diameter [m]
d Hole diameter [m]
h
E Activation energy [llmol]
E Eddy diffusivity [m's-l]
e Elementary charge (1.602 x 10-19 C) [C]
F, Force per mol of species i [N/mol]
F, Force per kg [N/kg]
FR Friction force [m-1]
f Fugacity [Pal
1;2 Friction coefficient [sm-']
5 Faraday constant (9.65.104 x C/mo!) [C/mol]
G Gibbs energy [1]
G NRTL Boltzmann factor [-]
u
GE Gibbs excess energy [1]
GJD Gibbs energy (ideal mixture) [1]
g Partial molar Gibbs energy [llmol]
g Acceleration due to gravity (9.81 m/s2) [m/s']
g(d) Break-up frequency of a droplet with diameter d [S-I]
g' UNIQUAC Gibbs combinatorial energy [llmol]
g' Partial molar Gibbs excess energy [llmol]
gJD Partial molar Gibbs energy (ideal mixture) [llmol]
gij NRTL Gibbs residual energy [llmol]
g" UNIQUAC Gibbs residual energy [llmol]
H Enthalpy [1]
HAc Acetic acid
Hel Hydrochloric acid
