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CHAPTER 3 SYNTHETIC FE-CONTAINING HYDRATES The presence of a second AFm phase was indicated by an intensive diffraction peak at 2θ = 10.7° (Fig. 27). This could indicate the presence of a second Fe-monosulfate compound with less water. The second Fe-monosulfate has an interlayer distance of 8.36(1) Å which could correspond to C4FsH10. The decrease in the interlayer distance from C4FsH12 (8.87 Å) to C4FsH10 (8.36 Å) is comparable to the difference in interlayer distance reported for C4AsH12 (8.94 Å) [88] and C4AsH10 (8.42 Å) [89]. The interlayer distance of the second AFm (C4FsH10) phase is between the value for C4FsH12 and the value of C4FcH12 (7.98 Å). Fig. 27 Details of the Rietveld plot from the sample Fe-Ms-50 °C. The structure of Fe-monosulfate is isotypic to Al-monosulfate. It has the same symmetry and same atomic positions with two kinds of disorder in the interlayer region: statistical distribution between one sulfate group with 2.3 water molecules and orientation disorder of sulfate groups (up or down). The refined composition is 73
CHAPTER 3 SYNTHETIC FE-CONTAINING HYDRATES [Ca2Fe(OH)6]·[(SO4)0.5·3.2(1)H2O]; i.e. C4AsH12.4(2). The crystallographic structure representations are identical to those previously determined for Al-monosulfate [87]. The interatomic distances determined for the refined Fe-monosulfate structure are listed in Table 16. Table 16 Refined interatomic distances in Fe-monosulfate (standard deviation is given in parentheses). Bond type Atoms Distances (Å) Ca-OH Ca-O1 3 x 2.25 (2) 3 x 2.40 (2) Ca-H2O Ca-O2 2.49 (3) Fe-OH Fe-O1 6 x 2.01 (2) S-O S-O3 3 x 1.44 (4) S-O4 1.48 (3) SO4-OH O3-O1 2.95 (5) O4-O1 2.80 (3) SO4-H2O O2-O3 3 x 2.87 (5) 3.2.5. Comparison of C4AsH12 with C4FsH12 Both Al-monosulfate and Fe-monosulfate crystallize in the rhombohedral R3 c symmetry. This structural similarity could enable a substitution of Al by Fe in the main layer structure. Fe 3+ (0.64 Å) has a slightly larger ion radius than Al 3+ (0.54 Å) which resulted in a larger unit cell parameter (a = 5.88 Å) for Fe-monosulfate than for Al- monosulfate (a = 5.76 Å). Raman spectroscopy was applied to study the vibrational frequency of the molecules in the structure of Fe-monosulfate. The results were compared with Al-monosulfate [79]. Raman spectroscopy measurements were carried out for the solids synthesized at 20 °C and 50 °C (Fig. 28 and Fig. 29). 74
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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 3 SYNTHETIC FE-CONTAINING H
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CHAPTER 4 FE-CONTAINING HYDRATES IN
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(Al+Fe)/Ca (Al+Fe)/Ca 0.8 0.6 0.4 0
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k 3 (k) CHAPTER 4 FE-CONTAINING HYD
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differentiated relative weight Weig
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Early reaction CHAPTER 4 FE-CONTAIN
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weight loss in % differentiated rel
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5. GENERAL CONCLUSION AND OUTLOOK a
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Speciation of iron(III) in hydrated
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5. GENERAL CONCLUSION AND OUTLOOK
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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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