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Dehydration behavior of FGD gypsum by simultaneous TG and DSC analysis

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Abstract

The dehydration behaviors of FGD gypsums from three power plants were investigated at N2 atmosphere (autogenous and negligible partial pressure of water, \( P_{{{\text{H}}_{ 2} {\text{O}}}} \)) in non-isothermal and isothermal condition. The dehydration of gypsum proceeded through one step, i.e., CaSO4·2H2O → γ-CaSO4 (γ-anhydrite) or two steps, i.e., CaSO4·2H2O → CaSO4·0.5H2O (hemihydrate) → γ-CaSO4 depending on temperature and \( P_{{{\text{H}}_{ 2} {\text{O}}}} \). The discrepancies of three FGD gypsums on dehydration behavior were very likely due to the different crystalline characteristics (size and habit) and impurities, such as fly ash and limestone. Experimental data of non-isothermal analysis have been fitted with two ‘model-free’ kinetic methods and those of isothermal analysis have been fitted with Avrami and linear equation. The apparent empirical activation energies (E a) suggest that the transition from gypsum to hemihydrate is mainly controlled by nucleation and growth mechanism, while the transition from gypsum to γ-anhydrite is mostly followed by phase boundary mechanism.

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References

  1. Freyer D, Voigt W. Crystallization and phase stability of CaSO4 and CaSO4-based salts. Monatsh Chem. 2003;134:693–719.

    CAS  Google Scholar 

  2. Solberg C, Evju C, Emanuelson A, Hansen S. Crystal structures of cementitious compounds. Part 3: calcium sulfates. ZKG Int. 2002;55:94–7.

    CAS  Google Scholar 

  3. Christensen AN, Olesen M, Cerenius Y, Jensen TR. Formation and transformation of five different phases in the CaSO4·H2O system: crystal structure of subhydrate β-CaSO4·0.5H2O and soluble anhydrite CaSO4. Chem Mater. 2008;20:2124–32.

    Article  CAS  Google Scholar 

  4. Charola AE, Pűhringer J, Steiger M. Gypsum: a review of its role in the deterioration of building materials. Environ Geol. 2007;52:339–52.

    Article  CAS  Google Scholar 

  5. Ballirano P, Melis E. Thermal behaviour and kinetics of dehydration of gypsum in air from in situ real-time laboratory parallel-beam X-ray powder diffraction. Phys Chem Mineral 2009;36:391–402.

    Article  CAS  Google Scholar 

  6. McAdie HG. The effect of water vapor upon the dehydration of CaSO4·2H2O. Can J Chem. 1964;42:792–801.

    Article  CAS  Google Scholar 

  7. Bushuev NN, Maslennikov BM, Borisov VM. X-ray diffraction investigation of CaSO4·0.67H2O. Russ J Inorg Chem. 1982;27:341–3.

    Google Scholar 

  8. Christensen AN, Lehmann MS, Pannetier J. A time-resolved neutron powder diffraction investigation of the hydration of CaSO4·1/2D2O and of the dehydration of CaSO4·2D2O. J Appl Cryst. 1985;18:170–2.

    Article  CAS  Google Scholar 

  9. Abriel W, Reisdorf K, Pannetier J. Dehydration reactions of gypsum: a neutron and X-ray diffraction study. J Solid State Chem. 1990;85:23–30.

    Article  CAS  Google Scholar 

  10. Putnis A, Winkler B. In situ IR spectroscopic and thermogravimetric study of the dehydration of gypsum. Mineral Mag. 1990;54:123–8.

    Article  CAS  Google Scholar 

  11. Strydom CA, Hudson-Lamb DL, Potgieter JH, Dagg E. The thermal dehydration of synthetic gypsum. Thermochim Acta. 1995;269(/270):631–8.

    Article  Google Scholar 

  12. Dos Santos VA, Pereira JAFR, Dantas CC. Kinetics of thermal dehydration of gypsum ore for obtaining beta hemihydrate in a fluidized bed. Bull Soc Chim Belg. 1997;6:253–60.

    Google Scholar 

  13. Chang H, Huang PJ, Hou SC. Application of thermo-Raman spectroscopy to study dehydration of CaSO4·2H2O and CaSO4·0.5H2O. Mater Chem Phys. 1999;58:12–9.

    Article  CAS  Google Scholar 

  14. Carbone M, Ballirano P, Caminiti R. Kinetics of gypsum dehydration at reduced pressure: an energy dispersive X-ray diffraction study. Eur J Mineral. 2008;20:621–7.

    Article  CAS  Google Scholar 

  15. Molony B, Ridge MJ. Kinetics of the dehydration of calcium sulphate dihydrate in vacuo. Aust J Chem. 1968;21:1063–5.

    Article  CAS  Google Scholar 

  16. Sarma LP, Prasad PSR, Ravikumar N. Raman spectroscopic study of phase transitions in natural gypsum. J Raman Spectrosc. 1998;29:851–6.

    Article  CAS  Google Scholar 

  17. Prasad PSR, Pradhan A, Gowd TN. In situ micro-Raman investigation of dehydration mechanism in natural gypsum. Curr Sci. 2001;80:1203–7.

    CAS  Google Scholar 

  18. Chio CH, Sharma SK, Muenow DW. Micro-Raman studies of gypsum in the temperature range between 9 K and 373 K. Am Mineral. 2004;89:390–5.

    CAS  Google Scholar 

  19. Prasad PSR, Chaitanya VK, Prasad KS, Rao DN. Direct formation of the γ-CaSO4 phase in dehydration process of gypsum: in situ FTIR study. Am Mineral. 2005;90:672–8.

    Article  CAS  Google Scholar 

  20. Ball MC, Norwood LS. Studies in the system calcium sulphate-water. Part I. Kinetics of dehydration of calcium sulphate dihydrate. J Chem Soc A. 1969;1633–7.

  21. Badens E, Llewellyn P, Fulconis JM, Jourdan Veesler CS, Boistelle R, et al. Study of gypsum dehydration by controlled transformation rate thermal analysis (CRTA). J Solid State Chem. 1998;139:37–44.

    Article  CAS  Google Scholar 

  22. Fatu D. Kinetics of gypsum dehydration. J Therm Anal Calorim. 2001;65:213–20.

    Article  CAS  Google Scholar 

  23. Hudson-Lamb DL, Strydom CA, Potgieter JH. The thermal dehydration of natural gypsum and pure calcium sulphate dehydrate (gypsum). Thermochim Acta. 1996;282(/283):483–92.

    Article  Google Scholar 

  24. Jordan G, Astilleros JM. In situ HAFM study of the thermal dehydration on gypsum (010) surfaces. Am Mineral. 2006;91:619–27.

    Article  CAS  Google Scholar 

  25. Strydom CA, Potgieter JH. Dehydration behaviour of a natural gypsum and a phosphogypsum during milling. Thermochim Acta. 1999;332:89–96.

    Article  CAS  Google Scholar 

  26. Cave SR, Holdich RG. The dehydration kinetics of gypsum in a fluidized bed reactor. Chem Eng Res Des. 2000;78:971–8.

    Article  CAS  Google Scholar 

  27. Deutsch Y, Nathan Y, Sarig S. Thermogravimetric evaluation of the kinetics of the gypsum-hemihydrate-soluble anhydrite transitions. J Therm Anal Calorim. 1994;42:159–74.

    Article  CAS  Google Scholar 

  28. Hamm H, Kersten HJ, Hueller R. 25 years experience gained in the European Gypsum Industry with the use of FGD gypsum. CEM Int. 2004;4:92–102.

    Google Scholar 

  29. Guan B, Yang L, Wu Z, Shen Z, Ma X, Ye Q. Preparation of α-calcium sulfate hemihydrate from FGD gypsum in K, Mg-containing concentrated CaCl2 solution under mild conditions. Fuel. 2009;88:1286–93.

    Article  CAS  Google Scholar 

  30. Follner S, Wolter A, Helming K, Silber C, Bartels H, Follner H. On the real structure of gypsum crystals. Cryst Res Tech. 2002;37:207–18.

    Article  CAS  Google Scholar 

  31. Brown ME, Maciejewski M, Vyazovkin S, Nomen R, Sempere J, Burnham A, et al. Computational aspects of kinetic analysis. Part A: the ICTAC kinetics project-data, methods and results. Thermochim Acta. 2000;355:125–43.

    Article  CAS  Google Scholar 

  32. Farjas J, Butchosa N, Roura P. A simple kinetic method for the determination of the reaction model from non-isothermal experiments. J Therm Anal Calorim. doi:10.1007/s10973-010-0737-5.

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Acknowledgements

The authors acknowledge greatly the financial support of this work by the fund of Chinese National Program for High Technology Research and Development (Project No. 2006AA03Z385), Science and Technology Plan of Zhejiang Province, China (Project No. 2007C23055).

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Authors and Affiliations

  1. Department of Environmental Engineering, Zhejiang University, Hangzhou, 310027, China

    Wenbin Lou, Baohong Guan & Zhongbiao Wu

  2. Department of Chemical Engineering, Ningbo University of Technology, Ningbo, 315016, China

    Wenbin Lou

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  1. Wenbin Lou
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Correspondence to Baohong Guan.

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Lou, W., Guan, B. & Wu, Z. Dehydration behavior of FGD gypsum by simultaneous TG and DSC analysis. J Therm Anal Calorim 104, 661–669 (2011). https://doi.org/10.1007/s10973-010-1100-6

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  • DOI: https://doi.org/10.1007/s10973-010-1100-6

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