Belay Zeleke Dilnesa - Eawag-Empa Library

More documents

Recommendations

Info

CHAPTER 2 MATERIALS AND METHODS the GEMS code was used, which is based on the PSI chemical thermodynamic database [44] merged with the slop98.dat database for temperature and pressure corrections [45]. 2.3.1. Estimation of heat capacity of Fe-containing phases The heat capacity, Cp°, of a solid can be expressed as a function of temperature using the parameters (a0, a1, a2 and a3) according to: Cp o = a0 + a1T + a2T -2 + a3T -0.5 In this study the heat capacities Cp° for Fe-containing phases were calculated based on the Cp° of the structurally similar Al-analogues [46] using reference reactions as shown in Table 3. If such reference reactions involve only solids and no “free” water, the change in heat capacity and the entropy is approximately zero [47, 48]. Table 3 Reference reactions used to estimate unknown heat capacities of cement minerals. Phases Reference reaction 3CaOFe2O3CaCO312H2O → 3CaOAl2O3CaSO412H2O - Al2O3 - CaSO4 + Fe2O3 +CaCO3 3CaOFe 2O 3Ca(CO 3) 0.510H 2O → 3CaOAl 2O 3CaSO 412H 2O - CaSO 42H 2O - Al 2O 3 + Fe 2O 3 + 0.5CaCO 3 + 0.5CaO 3CaOFe2O3CaSO412H2O → 3CaOAl2O3CaSO412H2O - Al2O3 + Fe2O3 3CaOFe2O3CaCl210H2O → 3CaOAl2O3CaSO412H2O - CaSO4 . 2H2O - Al2O3 + Fe2O3 + CaCl2 3CaOFe2O3Ca(OH)212H2O → 3CaOAl2O3CaSO412H2O - CaSO4 - Al2O3 + Fe2O3 + Ca(OH)2 3CaOFe 2O 36H 2O → 3CaOAl 2O 36H 2O - Al 2O 3 + Fe 2O 3 3CaOFe2O30.95SiO24.1H2O →3CaOAl2O36H2O - Al2O3 +0.95SiO2 + 1.9CaO -1.9Ca(OH)2+ Fe2O3 3CaO.Fe2O31.52 SiO2.2.96H2O →3CaOAl2O36H2O - Al2O3 +1.52SiO2 + 3.04CaO -3.04Ca(OH)2+ Fe2O3 3CaOAl2O30.41 SiO25.18H2O →3CaOAl2O36H2O +0.41SiO2 + 0.82CaO + 0.82Ca(OH)2 3CaOAl 2O 30.84 SiO 24.32H 2O →3CaOAl 2O 36H 2O +0.84SiO 2 + 1.68CaO + 1.68Ca(OH) 2 2.3.2. Determination of solubility products The measured composition of the liquid phase was used to calculate solubility products for the different solids. The activity coefficients of the dissolved species were calculated 25
CHAPTER 2 MATERIALS AND METHODS from the measured concentration. The activity coefficients of aqueous species yi were computed with the expanded extended Debye-Hückel equation in Truesdell-Jones form with individual parameters ai (dependent on ion size) and common third parameter by: 2 Ay zi log i 1 B a I by I I y i where zi denotes the charge of species i, I the effective molal ionic strength, by is a semi- empirical parameter (0.064 was used to calculate the solubility of Fe- monocarbonate/hemicarbonate and 0.123 for KOH electrolytes for the other Fe- containing phases at 25 °C), and Ay and By are P, T-dependent coefficients. This activity correction is thought to be applicable up to 1-2 M ionic strength [43]. The aqueous ion activities and speciation were calculated using the GEMS database relevant to the particular calculations. The solubility products were calculated from the activities obtained according to the reactions given in Table 4. From the calculated total solubility products, the Gibbs free energy of the reaction, according to: 0 r, T G RT ln K S 0, T at a temperature T was computed 0 r, T G where R = 8.31451J/(mol K) is the universal gas constant and T is the temperature in Kelvin. The temperature dependence of the solubility product of Fe-containing phases was computed based on the solubility measured at 20, 50 and 80 °C with the help of GEMS, using the built-in three-term temperature extrapolation function and the relationships shown in the equations below [49]. The three-term temperature extrapolation assumes 26
Page 1: Fe-containing hydrates and their fa
Page 4 and 5: The measured composition of the liq
Page 6 and 7: ZUSAMMENFASSUNG Thermodynamische Mo
Page 8 and 9: konnten die Fe-haltigen Hydrate im
Page 10 and 11: I owe to thank all the laboratory t
Page 12 and 13: Table 19 Compositions of Al/Fe-mono
Page 14 and 15: LIST OF FIGURES Fig. 1 Calculated v
Page 16 and 17: Fig. 34 Calculated solubility produ
Page 18 and 19: Fig. 62 Calculated solubility produ
Page 20 and 21: Table of Contents TABLE OF CONTENTS
Page 22 and 23: TABLE OF CONTENTS 3. SYNTHETIC FE
Page 24 and 25: TABLE OF CONTENTS 3.5.4. Solid solu
Page 26 and 27: 1 INTRODUCTION CHAPTER 1 INTRODUCTI
Page 28 and 29: CHAPTER 1 INTRODUCTION be formed. T
Page 30 and 31: cm 3 /100 g cement 85 80 75 70 65 6
Page 32 and 33: CHAPTER 1 INTRODUCTION 1.4 Characte
Page 34 and 35: CHAPTER 1 INTRODUCTION Fig. 4 Sampl
Page 36 and 37: CHAPTER 1 INTRODUCTION Identificat
Page 38 and 39: CHAPTER 2 MATERIALS AND METHODS han
Page 40 and 41: 3CaOAl2O3 + 6H2O → 3CaOAl2O36H2O
Page 42 and 43: CHAPTER 2 MATERIALS AND METHODS Tab
Page 44 and 45: CHAPTER 2 MATERIALS AND METHODS 2.2
Page 46 and 47: CHAPTER 2 MATERIALS AND METHODS fil
Page 48 and 49: CHAPTER 2 MATERIALS AND METHODS at
Page 52 and 53: CHAPTER 2 MATERIALS AND METHODS 0 t
Page 54 and 55: CHAPTER 2 MATERIALS AND METHODS Tab
Page 56 and 57: CHAPTER 2 MATERIALS AND METHODS 2.3
Page 58 and 59: CHAPTER 2 MATERIALS AND METHODS The
Page 60 and 61: CHAPTER 3 SYNTHETIC FE-CONTAINING H
Page 74 and 75: a). b). CHAPTER 3 SYNTHETIC FE-CONT
Page 80 and 81: o layer thickness (A) 8.0 7.8 7.6 C
Page 86 and 87: Phase log KSo CHAPTER 3 SYNTHETIC F
Page 88 and 89: volume [cm 3 ] 700 600 500 400 300
Page 100 and 101:
CHAPTER 3 SYNTHETIC FE-CONTAINING H
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Intensity [arb. units] Fe-Fr CHAPTE
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
CHAPTER 4 FE-CONTAINING HYDRATES IN
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
Page 180 and 181:
Page 182 and 183:
(Al+Fe)/Ca (Al+Fe)/Ca 0.8 0.6 0.4 0
Page 184 and 185:
Page 186 and 187:
Page 188 and 189:
k 3 (k) CHAPTER 4 FE-CONTAINING HYD
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
Page 196 and 197:
Page 198 and 199:
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 206 and 207:
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
Page 216 and 217:
APPENDIX APPENDIX Appendix A: Addit
Page 218 and 219:
Intensity (arb. Units) P Fe 2O 3 R
Page 220 and 221:
APPENDIX Appendix B7 XRD patterns o
Page 222 and 223:
REFERENCES REFRENCES [1] H.F.W. Tay
Page 224 and 225:
REFRENCES [29] M. Vespa, R. Dähn,
Page 226 and 227:
REFRENCES [54] M. Balonis, B. Lothe
Page 228 and 229:
REFRENCES [81] H.F.W. Taylor, Cryst
Page 230 and 231:
REFRENCES [107] K. Kyritsis, N. Mel
Page 232 and 233:
REFRENCES [134] M. Wilke, F. Farges
Page 235 and 236:
CURRCULUM VITAE Curriculum Vitae Na
show all

Belay Zeleke Dilnesa - Eawag-Empa Library

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?