Głównym celem autora było stworzenie podręcznika przedstawiającego praktyczne podstawy reologii, które powinien znać każdy ceramik. W większości teorii reologia, opisująca masy ceramiczne, jest przedstawiana za pomocą skomplikowanych wzorów matematycznych, mimo że powinna być prostym narzędziem umożliwiającym opisanie operacji jednostkowych. Książka ogranicza się do podstawowych zależności pozwalających na zrozumienie zachowania ciał poddanych naprężeniom. Omówiono w niej charakterystyczne właściwości reologiczne zawiesin, mas ceramicznych o konsystencji plastycznej oraz ziarnistych mas ceramicznych, a także metody pomiarowe. Szczególną uwagę poświęcono zachowaniu ziarnistych materiałów ceramicznych, które nie zostały dotąd wystarczająco dobrze zbadane na gruncie reologii, mimo że są bardzo często stosowane w przemyśle ceramicznym.
The author’s main purpose was to create a handbook showing practical foundations of rheology, which every ceramist should know. In most theories, rheology, which characterizes ceramic mass, is presented by means of complex mathematical formulas, even though it is supposed to be a simple tool, making description of unit operations possible. The book is limited to the essential relationships enabling an understanding of the behavior of bodies under stress. It presents the characteristic rheological properties of suspensions, ceramic masses with a plastic consistency, and granular ceramic masses, along with methods for measuring them. Particular attention is paid to the behavior of granular ceramic materials, which has not been sufficiently understood in the field of rheology, and these technologies are most frequently used in the ceramics industry.
- Contents
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Preface 9
Chapter 1
Introduction 15
1.1. Viscosity 16
1.2. Viscosity and rheological aspect 17
1.3. Rheology versus ceramics 17
1.4. Flowing 18
1.5. Summary 19
Chapter 2
Basics of rheology 21
2.1. Shear stress 21
2.2. Practical use of shear stress 22
2.3. Shear rate 23
2.4. Calculation and estimation of shear rate 24
2.5. Definition of viscosity 26
2.6. Summary 28
Chapter 3
Newtonian fluids (simple fluids) versus ceramic slurries 29
3.1. Concentration of suspensions 29
3.2. Weighing errors 35
3.3. The effects of phase stratification 36
3.4. Wall effects 36
3.5. Viscosity of suspensions 36
3.6. Grains sedimentation 38
3.7. Particle size distribution 39
3.8. Surface properties 39
3.9. Gelation, coagulation and flocculation 40
3.10. Shear rate in terms of grain collisions 41
3.11. Undesirable densification of the dispersed phase 41
3.12. Abrasion 41
3.13. Mechanical stabilization of suspensions 42
3.14. Flow of ceramic suspensions in tubular systems 42
3.15. The effect of chemical additives on the rheological properties of suspensions 43
3.16. Total dispersion 51
3.17. Strongly coagulated suspensions 52
3.18. Syneresis 52
3.19. The desired state of flocculation/deflocculation, coagulation/dispersion equilibrium 53
3.20. Summary 53
Chapter 4
Rheological models. Rheological equation of state 55
4.1. Mechanical models 57
4.2. Summary 82
Chapter 5
Non-Newtonian fluids versus ceramic slurries 85
5.1. Measurement of shear time – independent methods 100
5.2. Summary 102
Chapter 6
Non-reostable fluids versus ceramic slurries 105
6.1. Thixotropy 105
6.2. Stiffness of thixotropic structure 116
6.3. Rheopexy 121
6.4. Shear history (course)122
6.5. Gelation versus thixotropy 125
6.6. Rheopexy in aspect of intergrains collisions 126
6.7. Summary 127
Chapter 7
Attractive forces and gelation 129
7.1. Intermolecular attractive and repulsive forces 129
7.2. Summary 134
Chapter 8
Flow curves (rheograms). Equilibrium conditions 135
8.1. Properties of suspensions shear thinning during the shearing 135
8.2. Summary 136\
Chapter 9
Mechanical interaction of grain/medium and grain/grain in ceramic suspensions 137
9.1. Grain/medium mechanical interaction 137
9.2. Representative sampling in the flow 138
9.3. Flow in milling and stirring of ceramic slurries 140
9.4. Filtration and casting. Immobilized colloids 141
9.5. Grain abrasion in suspension flow 143
9.6. Grain/grain mechanical interaction 143
9.7. Summary 145
Chapter 10
Intermolecular repulsion forces and slurry dispersion. Chemical stabilization 147
10.1. Space, time and energy 147
10.2. Role of water in ceramic suspensions 149
10.3. Clay minerals and their properties in water systems 156
10.4. Three types of non-covalent bonds participating in intermolecular interactions 159
10.5. Chemical suspension stabilization 172
10.6. Characteristics of dispersant agents 188
10.7. Instability of dispersed slurries 205
10.8. Summary 207
Chapter 11
Dilatancy once more 211
11.1. Measurement of dilatant locks with a rheometer 216
11.2. Summary 219
Chapter 12
Syneresis in slurries and ceramic masses of plastic consistency 221
12.1. Recipes for ceramic masses 224
12.2. Summary 225
Chapter 13
Ceramic suspensions of plastic consistency 227
13.1. Rheological methods of determining plastic properties 230
13.2. Other methods of determining plastic properties of ceramic masses 239
13.3. Expansion of ceramic masses during forming 242
13.4. Summary 258
Chapter 14
Introduction to rheology of pseudo-non-rheostable suspensions 259
14.1. Clay-cement dispersions 259
14.2. Pseudo-non-rheostable ceramic-polymer suspensions 280
14.3. Optimization of the drying process 299
14.4. Summary 304
Chapter 15
Rheology of powders and ceramic granulated masses 307
15.1. Initial characteristics of granular ceramic masses 308
15.2. The migration phenomena of organic plasticizers during the granulation of ceramic masses by spray drying 345
15.3. Summary 348
Chapter 16
Rheology of masses granulated under external pressures 351
16.1. Flow curves (plasticization) 353
16.2. Consolidation time 359
16.3. Models of ceramic powders compaction by external stress. Equations densification 360
16.4. Summary 384
Chapter 17
Introduction to rheometry. Practical comments 385
17.1. Is shear rate high enough? 386
17.2. Simultaneous gelation and interactions of grains 387
17.3. Rheograms 388
17.4. Some advice on the measurement of apparent viscosity 391
17.5. Measurements in automatic rheometers 400
17.6. Determination of the most suitable addition of the dispersion agents 418
17.7. Evaluate thixotropic structure by the multistep test 423
17.8. Summary 425
Chapter 18
Control of other suspension parameters 427
18.1. Control of physical properties of grains 427
18.2. Medium (solvent) versus packing fraction 428
18.3. Control of chemical additives 433
18.4. Processes aging of suspensions 441
18.5. Mass components, partially soluble in water 443
18.6. The repair of symptoms or causes? 444
18.7. Summary 444
Chapter 19
Comments regarding the characteristics of granulated ceramic masses 447
19.1. The flow curve of ceramic loose masses 447
19.2. Rheological indicators of losse materials for the design of silos and other tanks.. 452
19.3. Other methods for measuring the shape of granules 455
19.4. The measurement of flowability of ceramic masses 457
19.5. Coefficient of internal frictionand coefficient of friction of granules on walls 458
19.6. Behaviour of ceramic granulated masses during flow. Flow stream properties 459
19.7. Summary 467
Appendices 469
Appendix A. Description of stresses 469
Appendix B. Description of deformations 477
Appendix C. Digression to the flow of the non-Newtonian reactive liquids 487
Appendix D. Conversion tables 491
Glossary 497
Bibliography 509
