Belay Zeleke Dilnesa - Eawag-Empa Library

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CHAPTER 3 SYNTHETIC FE-CONTAINING HYDRATES The total solubility product (ΣΠ) can be calculated using the equation below. The standard solid solution modeling in GEMS is setup for one ion substituting another ion in one crystallographic site per end member. To fulfill this condition the logK values were downscaled by a factor 2 ΣΠ= 2× ({Ca 2+ } 1.5 {AlO2 - + FeO2 - } 1 {HSiO3 - } 0.45 {OH - } 1.55 · {H2O} 1.1 ) Where {} denotes the activity. On the basis of the measured ion concentrations and target compositions of the solid phases, total solubility products were calculated as given Table 32. The total solubility products change as a function of Al/(Al + Fe) ratio. In the presence of Fe, Al-siliceous hydrogarnet has a lower solubility product at both 20 °C and 50 °C. A Lippmann phase diagram was drawn for the Ca3(AlxFe1-x)2(SiO4)0.9(OH)8.4 series assuming an ideal solid solution. The solidus and solutus curve describe the equilibrium state of the solid solution series of Al/Fe-siliceous hydrogarnet. Based on the limited amount of experimental data an ideal solid solution between Al and Fe-Si-hydrogarnet was fitted between C3AS0.84H4.32 and C3FS0.95H4.1. The solubility products of the end members are given in Table 32. The Lippmann phase diagram of the solidus curve as a function of the solid composition and the solutus curve as a function of the liquid compositions of an ideal solid solution series of Al/Fe-siliceous hydrogarnet was plotted at 20 °C and 50 °C as shown in Fig. 66a and b. If an ideal solid solution is assumed, the modeled total solubility products of solidus agrees reasonably with the experimentally determined total solubility products. The results indicate possible formation of an ideal solid solution between Al and Fe-siliceous hydrogarnet at 20 °C and 50 °C. However, the data might also be explained by the 141
CHAPTER 3 SYNTHETIC FE-CONTAINING HYDRATES complete absence of any solid solution as indicated by the dotted lines and the empty symbols in Fig. 66. Due to the formation of two miscibility gaps and the simultaneous presence of C3AS0.41H5.18, C3AS0.84H4.32, C3FS0.95H4.1, C3FS1.52H2.96 and C-S-H in varying amounts in the experiment, more detailed investigations are needed to derive a consistent thermodynamic model for this system. 142
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Fe-containing hydrates and their fa
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The measured composition of the liq
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ZUSAMMENFASSUNG Thermodynamische Mo
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konnten die Fe-haltigen Hydrate im
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I owe to thank all the laboratory t
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Table 19 Compositions of Al/Fe-mono
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LIST OF FIGURES Fig. 1 Calculated v
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Fig. 34 Calculated solubility produ
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Fig. 62 Calculated solubility produ
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Table of Contents TABLE OF CONTENTS
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TABLE OF CONTENTS 3. SYNTHETIC FE
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TABLE OF CONTENTS 3.5.4. Solid solu
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1 INTRODUCTION CHAPTER 1 INTRODUCTI
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CHAPTER 1 INTRODUCTION be formed. T
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cm 3 /100 g cement 85 80 75 70 65 6
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CHAPTER 1 INTRODUCTION 1.4 Characte
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CHAPTER 1 INTRODUCTION Fig. 4 Sampl
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CHAPTER 1 INTRODUCTION Identificat
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CHAPTER 2 MATERIALS AND METHODS han
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3CaOAl2O3 + 6H2O → 3CaOAl2O36H2O
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CHAPTER 2 MATERIALS AND METHODS Tab
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CHAPTER 2 MATERIALS AND METHODS 2.2
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CHAPTER 2 MATERIALS AND METHODS fil
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CHAPTER 2 MATERIALS AND METHODS at
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CHAPTER 2 MATERIALS AND METHODS the
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CHAPTER 2 MATERIALS AND METHODS 0 t
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CHAPTER 2 MATERIALS AND METHODS Tab
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CHAPTER 2 MATERIALS AND METHODS 2.3
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CHAPTER 2 MATERIALS AND METHODS The
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CHAPTER 3 SYNTHETIC FE-CONTAINING H
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a). b). CHAPTER 3 SYNTHETIC FE-CONT
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o layer thickness (A) 8.0 7.8 7.6 C
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Phase log KSo CHAPTER 3 SYNTHETIC F
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volume [cm 3 ] 700 600 500 400 300
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Page 116 and 117: CHAPTER 3 SYNTHETIC FE-CONTAINING H
Page 118 and 119: Intensity [arb. units] Fe-Fr CHAPTE
Page 172 and 173: CHAPTER 4 FE-CONTAINING HYDRATES IN
Page 182 and 183: (Al+Fe)/Ca (Al+Fe)/Ca 0.8 0.6 0.4 0
Page 188 and 189: k 3 (k) CHAPTER 4 FE-CONTAINING HYD
Page 200 and 201: differentiated relative weight Weig
Page 202 and 203: Early reaction CHAPTER 4 FE-CONTAIN
Page 204 and 205: weight loss in % differentiated rel
Page 208 and 209: 5. GENERAL CONCLUSION AND OUTLOOK a
Page 210 and 211: Speciation of iron(III) in hydrated
Page 212 and 213: 5. GENERAL CONCLUSION AND OUTLOOK
Page 214 and 215: Techniques XRD X-ray diffraction TG
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APPENDIX APPENDIX Appendix A: Addit
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Intensity (arb. Units) P Fe 2O 3 R
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APPENDIX Appendix B7 XRD patterns o
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REFERENCES REFRENCES [1] H.F.W. Tay
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REFRENCES [29] M. Vespa, R. Dähn,
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REFRENCES [54] M. Balonis, B. Lothe
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REFRENCES [81] H.F.W. Taylor, Cryst
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REFRENCES [107] K. Kyritsis, N. Mel
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REFRENCES [134] M. Wilke, F. Farges
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CURRCULUM VITAE Curriculum Vitae Na
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