Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
권호 표지
DOI QR코드

DOI QR Code

Fabrication of lightweight geopolymer based on the IGCC slag

IGCC 용융 슬래그를 이용한 경량 지오폴리머 제조

  • Park, Soo-bin (Department of Advanced Material Engineering, Kyonggi University) ;
  • Kim, Kang-duk (Department of Advanced Material Engineering, Kyonggi University) ;
  • Kang, Seung-gu (Department of Advanced Material Engineering, Kyonggi University)
  • 박수빈 (경기대학교 신소재공학과) ;
  • 김강덕 (경기대학교 신소재공학과) ;
  • 강승구 (경기대학교 신소재공학과)
  • Received : 2017.10.25
  • Accepted : 2017.11.21
  • Published : 2017.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, a lightweight geopolymer was prepared using by slag discharged from IGCC (Integrated Gasification Combined Cycle) power plant and its physical properties, the density and compressive strength, were analyzed as a function of the concentration of alkali activators, W/S ratio and aging times. Also the possibility of applying it to lightweight materials by adding Si sludge as a foaming agent to the geopolymerg was investigated. In particular, a complex composition of alkali activator and a pre-curing process were applied to improve the strength properties of lightweight geopolymers. While the compressive strength of the lightweight geopolymer using a single activator was 9.5 MPa, the specimen made with a complex composition of alkali activator had compressive strength of 2~5 times higher. In addition, the lightweight geopolymer with pre-curing process showed a compressive strength value of 18~48 % higher than that of specimen made with no precuring process. In this study, by using a complex activator and a pre-curing process. the maximum compressive strength of lightweight geopolymer was obtained as 40 MPa (The specimen was aged for 3 days and had density of $1.83g/cm^3$), which is comparable to cement concrete. By analyzing the crystal phase and microstructure of geopolymers obtained in this study using by XRD and SEM, respectively, it was confirmed that the flower-bud-like zeolite crystal was homogeneously distributed on the surface of the C-S-H gel (sodium silicate hydrate gel) in the geopolymer.

본 연구에서는, IGCC(Integrated Gasification Combined Cycle: 석탄가스화 복합발전)에서 배출되는 용융 슬래그로 부터 지오폴리머를 제조하여 알칼리 활성화제의 몰농도, W/S 비(water/ solid ratio), 재령일에 따른 비중과 압축강도 등 물리적 특성을 분석함과 동시에 발포제인 Si 슬러지를 첨가하여 경량화 소재로서의 가능성을 고찰하였다. 특히 경량 지오폴리머의 강도 특성향상을 위하여 복합 활성화제 및 pre-curing 공정을 적용하였다. 단일 활성화제를 사용한 경량 지오폴리머의 압축 강도는 9.5 MPa이었으나, 복합 활성화제로 제조할 경우 2~5배 정도의 압축강도 증진 효과를 나타내었다. 더군다나, pre-curing을 실시한 경량 지오폴리머의 경우, pre-curing하지 않은 시편들에 비해 18~48 % 가량 높은 압축강도 값을 보였다. 본 연구에서 복합 활성화제와 pre-curing 공정의 도입으로 얻어진 경량 지오폴리머의 최고 압축강도는 40 MPa(3일 재령하여 밀도가 $1.83g/cm^3$인 시편)로서 시멘트 콘크리트에 필적하였다. XRD 결정상 분석과 SEM을 이용한 미세구조 분석을 통하여 지오폴리머 표면에서 C-S-H 겔(sodium silicate hydrate gel)의 모상에 꽃봉오리 모양의 zeolite 결정상이 균일하게 분포된 것을 확인할 수 있었다.

Keywords

References

  1. A.O. Pudon, "The action of alkali on blast-furnace slag", J. Soc. Che. Ind. 59 (1940) 191. https://doi.org/10.1002/jctb.5000591202
  2. J. Davidovits, "Geopolymers: Inorganic polymeric new materials", J. Therm. Analysis 37 (1991) 1633. https://doi.org/10.1007/BF01912193
  3. J.-H. Lee, J.-H. Kim, Y.-R. Kim, S.-P. Kang, S.-J. Choi and M.-H. Kim, "An experimental study on the properties of concrete using bottom ash according to watercement ratio", Kor. Inst. Bldg. Const. 2 (2002) 57.
  4. D.-G. Kim, J.-H. Lee, H.-J. Lee and J.-H. Kim, "Effects of water-cement ratio on the freeze thaw resistance of fly ash concrete", Kor. Inst. Bldg. Const. 22 (2010) 211.
  5. U. Rattanasak and P. Chindaprasirt, "Influence of NaOH solution on the synthesis of fly ash geopolymer", Min'l Eng. 22 (2009) 1073. https://doi.org/10.1016/j.mineng.2009.03.022
  6. C. Tippayasam, S. Boonsalee, S. Sajjavanich, C. Ponzoni, E. Kamseu and D. Chaysuwan, "Geopolymer development by powders of metakaolin and wastes in thailand", Adv. Sci. Tech. 69 (2010) 63. https://doi.org/10.4028/www.scientific.net/AST.69.63
  7. Q. Zhao, B. Nair, T. Rahimian and P. Balaguru, "Novel geopolymer based composites with enhanced ductility", J. Mater. Sci. 42 (2007) 3131. https://doi.org/10.1007/s10853-006-0527-4
  8. S. Kumar and R. Kumar, "Mechanical activation of fly ahs: Effect on reaction, structure and properties of resulting geopolymer", Cer. Int. 37 (2011) 533. https://doi.org/10.1016/j.ceramint.2010.09.038
  9. E. Kamseu, A. Rizzuti, C. Leonelli and D. Perera, "Enhanced thermal stability in $K_2O$-metakaolin-based geopolymer concretes by $Al_2O_3$ and $SiO_2$ fillers addition", J. Mater. Sci. 45 (2010) 1715. https://doi.org/10.1007/s10853-009-4108-1
  10. W. Rickard, L. Vickers and A.V. Riessen, "Performance of fibre reinforced, low density metakaolin geopolymers under simulated fire conditions", App. Clay Sci. 73 (2012) 71.
  11. K.B. Han, "Current state of lightweight aggregate concrete and future perspective for artificial lightweight aggregate production", Kor. Const. Safety Association 33 (2005) 34.
  12. Z. Zhang, J.L. Provis, A. Reid and H. Wang, "Geopolymer foam concrete: An emerging material for sustainable construction", Const. Bldg. Mat. 56 (2014) 113.
  13. V. Medri and A. Ruffini, "The influence of process parameters on in situ inorganic foaming of alkalibonded SiC based foams", Cer. Int. 38 (2012) 3351. https://doi.org/10.1016/j.ceramint.2011.12.045
  14. V. Medri, E. Papa, J. Dedecek, H. Jirglova, P. Benito, A. Vaccari and E. Landi, "Effect of metallic Si addition on polymerization degree of in situ foamed alkali-aluminosilicates", Cer. Int. 39 (2013) 7657. https://doi.org/10.1016/j.ceramint.2013.02.104
  15. A.D. Hounsi, G.L. Nana, G. Djeteli, P. Blanchart, D. Alowanou, P. Kpelou, K. Napo, G. Tchangbedji and M. Praisler, "How does Na, K alkali metal concentration change the early age structural characteristic of kaolinbased geopolymers", Cer. Int. 40 (2014) 8953. https://doi.org/10.1016/j.ceramint.2014.02.052
  16. P. Duxon, A.F. Jimenez, J.L. Provis, G.C. Lukey, A. Palomo and J.S.J.V. Deventer, "Geopolymer technology: the current state of the art", J. Mater. Sci. 42 (2007) 2917. https://doi.org/10.1007/s10853-006-0637-z
  17. P. Chindaprasirt, C. Jaturapitakkul, W. Chalee and U. Rattanasak, "Comparative study on the characteristics of fly ash and bottom ash geopolymers", Waste Mngt. 29 (2009) 539. https://doi.org/10.1016/j.wasman.2008.06.023
  18. G.-S. Ryu, K.-T. Koh and Y.-S. Chung, "Analysis of mechanical properties and microstructure of fly ash based alkail-activated mortar", J. Kor. Inst. Res. Rec. 21 (2012) 27.
  19. J.G.S.V. Jaarsveld and J.S.J.V. Deventer, "Effect of the alkali metal activator on the properties of fly ash-based geopolymers", Ind. Eng. Chem. Res. 38 (1999) 3932. https://doi.org/10.1021/ie980804b
  20. T. Bakharev, "Geopolymeric materials prepared using Class F fly ash and elevated temperature curing", Cem. Conc. Res. 35 (2005) 1224. https://doi.org/10.1016/j.cemconres.2004.06.031
  21. Z. Aly, E.R. Vance, D.S. Perera, J.V. Hanna, C.S. Griffith, J. Davis and D. Durce, "Aqueous leachability of metakaolin-based geopolymers with mole ratios of Si/ Al = 1.5-4", J. Nucl. Mater. 378 (2008) 172. https://doi.org/10.1016/j.jnucmat.2008.06.015
  22. L. Weng and K.S. Crentsil, "Dissolution processes hydrolysis and condensation reactions during geopolymer synthesis:part I-low Si/Al ratio systems", J. Mater. Sci. 42 (2007) 2997. https://doi.org/10.1007/s10853-006-0820-2
  23. P. Rovnanik, "Effect of curing temperature on the development of hard structure of metakaolin-based geopolymer", Const. Bldg. Mater. 24 (2010) 1176. https://doi.org/10.1016/j.conbuildmat.2009.12.023
  24. S. Delair, E. Prud'homme, C. Peyratout, A. Smith, P. Michaud, L. Eloy, E. Joussein and S. Rossignol, "Durability of inorganic foam in solution: The role of alkali elements in the geopolymer network", Corr. Sci. 59(2012) 213. https://doi.org/10.1016/j.corsci.2012.03.002
  25. J.-T. Kim, D.-S. Seo, G.-J. Kim and J.-K. Lee, "Influence of alkaline-activator content on the compressive strength of aluminosilicate-based geopolymer", J. Kor. Cer. Soc. 47 (2010) 216. https://doi.org/10.4191/KCERS.2010.47.3.216
  26. Concrete Standard Specification of Korea, Ministry of Land, Infrastructure and Transport (2016).
  27. S.V. Joshi and M.S. Kadu, "Role of alkaline activator in development of eco-friendly fly ash based geo polymer concrete", Int. J. Evmnt. Sci. Dev. 3 (2012) 417.
  28. H. Xu and J.S.J.V. Deventer, "The geopolymerisation of alumino-silicate minerals", Int. J. Min'l Proc. 59 (2000) 247. https://doi.org/10.1016/S0301-7516(99)00074-5
  29. J.T. Gourley, Paper presented at Materials 2003 Conference: Adap. Mater. Modern Soc., Sydney (2003).
  30. A. Shoumkova and V. Stoyanova, "Zeolites formation by hydrothermal alkali activation of coal fly ash from thermal power station 'Maritsa 3'", Bulgaria, Fuel 103 (2013) 533.