Journal of Thermal Analysis and Calorimetry

, Volume 119, Issue 3, pp 2119–2126 | Cite as

Effects of kaolinite addition on the melting characteristics of the reaction between phosphogypsum and CaS

  • Lijing Zhao
  • Tianming Wan
  • Xiushan Yang
  • Lin Yang
  • Xingjian Kong
  • Zhiye Zhang
  • Xinlong Wang


Phosphogypsum is a type of solid waste that causes severe environmental damage. To utilize phosphogypsum more effectively, the present study investigated the melting characteristics of the reaction between phosphogypsum and CaS. FactSage was used to calculate the phase equilibrium and to predict the melting behavior at high temperatures. The analysis comprised an ash-melting temperature test, thermogravimetric analysis, differential thermal analysis, and scanning electron microscopy. The results showed that kaolinite had major effects on the ash-melting temperature and the ash-melting behavior, where the effects depended on the kaolinite content. The ash-melting temperature increased with the addition of kaolinite. With a kaolinite content of 10 %, the increases in the deforming temperature, softening temperature, hemispheric temperature, and flowing temperature were 50, 42, 49, and 65 °C, respectively. The results of the simulation and experimental analyses were in good agreement.


FactSage Kaolinite Melting characteristics Phosphogypsum 



This research was supported by the National High Technology Research and Development Program of China (Grant No. 2011AA06A106), which is gratefully acknowledged. FactSage 6.1 was provided by Kunming University of Science and Technology.


  1. 1.
    Parreira A, Kobayashi A, Silvestre O Jr. Influence of Portland cement type on unconfined compressive strength and linear expansion of cement-stabilized phosphogypsum. J Environ Eng. 2003;129(10):956–60.CrossRefGoogle Scholar
  2. 2.
    Yang X, Zhang Z, Wang X, Yang L, Zhong B, Liu J. Thermodynamic study of phosphogypsum decomposition by sulfur. J Chem Thermodyn. 2013;57:39–45.CrossRefGoogle Scholar
  3. 3.
    Rutherford P, Dudas M, Samek R. Environmental impacts of phosphogypsum. Sci Total Environ. 1994;149(1):1–38.CrossRefGoogle Scholar
  4. 4.
    Tayibi H, Choura M, López FA, Alguacil FJ, López-Delgado A. Environmental impact and management of phosphogypsum. J Environ Manag. 2009;90(8):2377–86.CrossRefGoogle Scholar
  5. 5.
    Alva A, Sumner M. Amelioration of acid soil infertility by phosphogypsum. Plant Soil. 1990;128(2):127–34.CrossRefGoogle Scholar
  6. 6.
    Carvalho M, Van Raij B. Calcium sulphate, phosphogypsum and calcium carbonate in the amelioration of acid subsoils for root growth. Plant Soil. 1997;192(1):37–48.CrossRefGoogle Scholar
  7. 7.
    El Didamony H, Abd S, Aleem E, Aziz M. Untreated phosphogypsum as a set retarder for slag cement production. Ind Ceram. 2003;23(1):19–24.Google Scholar
  8. 8.
    Ilić M, Miletić S, Munitlak R. Utilization of the waste phosphogypsum for the Portland cement clinker production. Toxicol Environ Chem. 1999;69(1–2):201–7.Google Scholar
  9. 9.
    Lutz R. Preparation of phosphoric-acid waste gypsum for further processing to make building-materials. Zement-Kalk-Gips. 1994;47(12):690.Google Scholar
  10. 10.
    Ma L, Ning P, Zheng S, Niu X, Zhang W, Du Y. Reaction mechanism and kinetic analysis of the decomposition of phosphogypsum via a solid-state reaction. Ind Eng Chem Res. 2010;49(8):3597–602.CrossRefGoogle Scholar
  11. 11.
    Oh JS, Wheelock T. Reductive decomposition of calcium sulfate with carbon monoxide: reaction mechanism. Ind Eng Chem Res. 1990;29(4):544–50.CrossRefGoogle Scholar
  12. 12.
    Ölmez H, Yilmaz V. Infrared study on the refinement of phosphogypsum for cements. Cem Concr Res. 1988;18(3):449–54.CrossRefGoogle Scholar
  13. 13.
    Reijnders L. Cleaner phosphogypsum, coal combustion ashes and waste incineration ashes for application in building materials: a review. Build Environ. 2007;42(2):1036–42.CrossRefGoogle Scholar
  14. 14.
    Singh M. Treating waste phosphogypsum for cement and plaster manufacture. Cem Concr Res. 2002;32(7):1033–8.CrossRefGoogle Scholar
  15. 15.
    X-l Z, L-h H. Studies on technology of cement integrated with sulfuric acid produced from phosphogypsum. Shandong Chem Ind. 2007;1:008.Google Scholar
  16. 16.
    Aagli A, Tamer N, Atbir A, Boukbir L, El Hadek M. Conversion of phosphogypsum to potassium sulfate. J Therm Anal Calorim. 2005;82(2):395–9.CrossRefGoogle Scholar
  17. 17.
    Jianxi L, Su Y, Liping M. Feasibility analysis for decomposition of phosphogypsum in cement precalciner. Environ Prog Sustain Energy. 2011;30(1):44–9.CrossRefGoogle Scholar
  18. 18.
    Van der Merwe E, Strydom C, Potgieter J. Thermogravimetric analysis of the reaction between carbon and CaSO4 2H2 O, gypsum and phosphogypsum in an inert atmosphere. Thermochim Acta. 1999;340:431–7.CrossRefGoogle Scholar
  19. 19.
    Strydom C, Groenewald E, Potgieter J. Thermogravimetric studies of the synthesis of cas from gypsum, CaSO4 2H2O and phosphogypsum. J Therm Anal Calorim. 1997;49(3):1501–7.CrossRefGoogle Scholar
  20. 20.
    Chen JM, Yang RT. Fluidized-bed combustion of coal with lime additives. Kinetics and mechanism of regeneration of the lime sorbent. Ind Eng Chem Fundam. 1979;18(2):134–8.CrossRefGoogle Scholar
  21. 21.
    Davies N, Hayhurst A. On the formation of liquid melts of CaS and CaSO4 and their importance in the absorption of SO2 by CaO. Combust Flame. 1996;106(3):359–62.CrossRefGoogle Scholar
  22. 22.
    Gruncharov I, Pelovski Y, Bechev G, Dombalov I, Kirilov P. Effects of some admixtures on the decomposition of calcium sulphate. J Therm Anal. 1988;33(3):597–602.CrossRefGoogle Scholar
  23. 23.
    Vorres KS. Effect of composition on melting behavior of coal ash. J Eng Gas Turbines Power. 1979;101(4):497–9.CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2015

Authors and Affiliations

  • Lijing Zhao
    • 1
  • Tianming Wan
    • 1
  • Xiushan Yang
    • 1
  • Lin Yang
    • 1
  • Xingjian Kong
    • 1
  • Zhiye Zhang
    • 1
  • Xinlong Wang
    • 1
  1. 1.School of Chemical EngineeringSichuan UniversityChengduPeople’s Republic of China

Personalised recommendations