Journal of the Korean Recycled Construction Resources Institute (한국건설순환자원학회논문집)

Korean Recycled Construction Resources Institute (한국건설순환자원학회)
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Effect of Blast Furnace Slag and Desulfurized Gypsum on Hardening of CFBC Boiler Coal Ash

CFBC 보일러 석탄회의 경화에 대한 고로슬래그, 탈황석고의 영향

  • Lee, Woong-Geol (Research Center of Advanced Convergence Process on Materials, Kangwon University) ;
  • Kim, Jin-Ho (Center of Research Facilities KNU, Kangwon University) ;
  • Kim, Kyung-Nam (Department of Advanced Materials Engineering, Kangwon University) ;
  • Song, Myong-Shin (Research Center of Advanced Convergence Process on Materials, Kangwon University)
  • 이웅걸 (강원대학교 삼척캠퍼스 재료융합공정연구소) ;
  • 김진호 (강원대학교 공동실험실습관) ;
  • 김경남 (강원대학교 신소재공학과) ;
  • 송명신 (강원대학교 삼척캠퍼스 재료융합공정연구소)
  • Received : 2021.09.27
  • Accepted : 2021.12.03
  • Published : 2021.12.30
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Abstract

The effects of blast furnace slag(BFS) and desulfurized gypsum(FDG) on the compressive strength of CFBA, and self-hydration of CFBA were studied. CFBA has self-hydrating and hardening properties, and it can be seen that the compressive strength of CFBA can be improved by using appropriate amounts of BFS and FDG. In addition, the self-hardening properties of CFBA are similar to the hydration reaction of 4CaO·Al2O3·Fe2O3 (C4AF), a cement clinker mineral, and when free-CaO, CaSO4 and CaCO3 coexist, Compressive strength of CFBA is expressed by the formation of calcium carbo compounds and hydrates of ettringite, calcium silicate, and calcium aluminate.

순환유동층보일러 석탄회(CFBA)는 탈황공정을 위한 석회석 투입에 의한 탈황석고와 free-CaO에 의해 자기경화되는 특성이 있는 것으로 알려져 있다. 본 연구에서는 시멘트 바인더 대체용 CFBA의 자가경화에 대한 고로슬래그(BFS)와 탈황석고(FDG)의 영향을 검토하였다. 다량의 Fe2O3, free-CaO 및 탈황 석고를 함유하는 CFBA의 수화반응에 의한 압축강도는 칼슘알루미네이트 수화물, 칼슘실리케이트 수화물, 에트링자이트 및 칼슘카보페라이트 수화물(3CaO·Fe2O3·3CaCO3·12H2O)의 형성에 기인한다. CFBA의 자가 경화에 의한 압축강도는 Ordinary Portland Cement에서 C4AF의 수화물과 유사한 수화물을 생성하여 표현하며, C4AF의 수화시 CaSO4가 존재하면 CaSO4가 CaO·Al2O3와 에트링자이트를 형성하고, 유리 CaO와 CaCO3가 함께 존재하면 육방정계 결정인 탄산칼슘 또는 탄산칼슘 결정이 형성됩니다. CFBA의 경화 특성은 C4AF의 수화 및 경화 메커니즘에 의해 유사한 특성을 가짐을 확인하였다.

Keywords

Acknowledgement

본 연구는 국토교통부/국토교통과학기술진흥원의 지원으로 수행되었음(과제 번호 21CTAP-C163942-01).

References

  1. Dung, N.T., Chang, T.P., Chen, C.Y. (2015). Hydration process and compressive strength of sag-CFBC fly ash materials without Portland cement, Journal of Materials in Civil Engineering, 27(7), 1-9.
  2. El-Alfi, S., ABD-Aleem, S., El-Didamony, H. (2001) Hydration of C4AF in the presence of artificial CaSO4 and lime, Indian Joural of Engineering and Materials Sciences, 8, 292-296.
  3. Kang, Y.H., Jung, S.H. (2017). Material properties of circulating fluidized bed combustion fly ash and utilization of non-sintered cement field, Magazine of RCR, 12(2), 26-32 [in Korean]. https://doi.org/10.14190/MRCR.2017.12.2.026
  4. Korea South East Power Co.. (2011). "Technology for Constructing and Operating Eco-Friendly Circulating Fluidized Bed Boilers", KEPIC-Week
  5. Lee, H,S., Kim, J.H., Lee, J.Y., Chung, C.W. (2017). Use of flue gas desulfurization gypsum as an activator for a ground granulated blast furnace slag, Journal of the Korea Institute of Building Construction, 17(4), 313-320 [in Korean]. https://doi.org/10.5345/JKIBC.2017.17.4.313
  6. Li, C., Sun, H., Li, L. (2010). A review: The comparison between alkali-activated slag(Si+ Ca) and metakaolin (Si+ Al) cements, Cement and Concrete Research, 40(9), 1341-1349. https://doi.org/10.1016/j.cemconres.2010.03.020
  7. Lim, Y.J. (2002). Characteristics and Application Control Accelerator for Non-Sintered Cement Based on Blast Furnace Slag, Ph.D Thesis, Kunsan National University [in Korean].
  8. Moon, H.Y., Shin, D.G. (2005). Effect of alkali activators on early compressive strength of blast-furnace slag mortar, Journal of the Korea Institute for Structural Maintenance and Inspection, 9(3), 120-128 [in Korean].
  9. Park, J.T., Jung, G.S., Kang, C.H., Oh, H.S. (2020). The feasibility study for utilization of blended cement as a activator of bottom ash from circulating fluidized bed combuster boiler, Journal of the Korean Recycled Construction Resources Institute, 8(3), 255-258 [in Korean]. https://doi.org/10.14190/JRCR.2020.8.3.255
  10. Radwan, M.M., El, H. S. (2011). Hydration characteristics of tetracalcium alumino-ferrite phase in the presence calcium carbonate, Ceramics-Silikaty, 55(4), 337-342.
  11. Rogers, D.E., Aldridge, L.P. (1977). Hydrates of calcium ferrites and calcium aluminoferrites, Cement and Concrete Research, 7(4), 399-409. https://doi.org/10.1016/0008-8846(77)90068-0
  12. Sheng, G., Li, Q., Zhai, J., Li, F. (2007). Self-cementitious properties of fly ashes from CFBC boilers co-firing coal and high-sulphur petroleum coke, Cement and Concrete Research, 37(6), 871-876. https://doi.org/10.1016/j.cemconres.2007.03.013
  13. Shi, C., Day, R.L. (1995). A calorimetric study of early hydration of alkali-slag cements, Cement and Concrete Research, 25(6), 1333-1346. https://doi.org/10.1016/0008-8846(95)00126-W
  14. Zhang, G., Ren, Q., He, J., Jiang, S., Cheng, X., Yu, Y. (2021). New understanding of early hydration of C4AF under surface vitrifcation, Powder Technology, 377, 372-378. https://doi.org/10.1016/j.powtec.2020.08.098