Fundamentals of Reology in Ceramic Processes

Opis

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.

Spis treści

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

Informacje o bezpieczeństwie produktu Informacje o producencie