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1 Journal of the Korean Ceramic Society Vol. 45, No. 7, pp. 395~400, Preparation and its Characteristics of Fly Ash-based Geopolymeric Mortar using Low Grade Silica Waste Se Gu Son, Seung Yeob Hong, and Young Do Kim GEOHWA E.S.R Research Center, Chuncheon , Korea (Received May 15, 2008; Accepted July 2, 2008) ³ y w Fly Ash s k p Áy Á½ y» ( ; ) ABSTRACT This paper indicates the investigation about the development of ET (Environmental Technology) industrial geopolymeric materials from mixture silica mine waste, coal fly ash and alkali activator solution (sodium silicate) by the geopolymer technique at ambient temperature. The results showed that higher compressive strength of geopolymeric mortar increased with a reduce of L/S ratio and increased along with an increase of coal fly ash content. The compressive strengths of geopolymer mortar on low silica of C Silica Mine and K Silica Mine are 18.7 MPa, 20.4 MPa, respectively. Compressive strength of geopolymeric mortar depends on L/S ratio and coal fly ash content added. Additionally, scanning electron microscope (SEM) techniques are used to characterize the microstructure of the geopolymeric mortars. SEM observation shows that it is possible to have amorphous aluminosilicate gel within mortar. XRD patterns indicate the fact that geopolymeric mortar is composed of amorphous aluminosilicate phase, calcite and quartz. Key words : Geopolymeric mortar, Silica waste, Fly ash, Amorphous phase 1. Geopolymer e f p p, sp p w, û CO 2 wì» yw p š y p w p» š. 1-6) Geopolymer 3 ƒ š p w,. Geopolymer fly ash, metakaolin, blast furnace slag silica w wš natural silicate mineral ƒ w. Geopolymer phw e w ù Ÿ l Si 4+ Al 3+ wwš w ww w, xk Mn(-(SiO 2 )z-alo 2 )n, wh 2 O.» M e, ùp, e e ƒ j, Z 1, 2, 3, n w w ùkü. 2) Ikeda 7-9) geopolymer v y y wš. v» y v y Corresponding author : Se Gu Son sgson@hanmail.net Tel : Fax : v w. y v p w ³ š, y v geopolymerization w -O-Si-O- M-O-Si-O- w w w œw. w y y y v w j z w w œ w w. geopolymer technique w y v quartzƒ t w ³ wš, t w v y v, y y œ ³ w geopolymeric k w š p w. 2. x 2.1. Geopolymeric k w» w y v ü C ³ Ÿ (Q1) K³ Ÿ (Q2) l ³, y v A v w, y y q 3y Na 2 SiO 3 ƒ 2.8M(SiO 2 /Na 2 O 2.2) NaOH w w z w. y y SiO 2ƒ 18.5%, Na 2 Oƒ 8.8%. 395

2 396 Áy Á½ Table 1. Physical and Chemical Properties of Start Materials Unit: wt% SiO 2 Al 2 O 3 CaO Fe 2 O 3 MgO Na 2 O Particle size (µm) Q Q Fly Ash(FA) Fig. 1. Scanning electron micrographs of starting materials (a) Q1, (b) Q2, and (c) FA. yw s³ j» Table 1 ùkü. Table ³ Q1 SiO wt% w wš, Q2 SiO 2 w 65.0 wt%. v D ky x ü g w wz Fig. 2. XRD patterns of low grade silica minerals (a) Q1, (b) Q2, and (c) FA. wš t w. v yw SiO 2 Al 2 O 3 w ƒƒ 47.2% 25.7%, CaOƒ 14.7% CaO w p š,»k Fe 2 O 3, Na 2 O, MgO. w j» Q µm ƒ jš, Q2ƒ

3 ³ y w Fly Ash s k p 397 Table 2. Mixture Proportions of Geopolymeric Mortar Solid(wt%) Q1 Q2 FA Liquid/Solid (L/S) Curing temp. ( o C) Q1FL Q1FL Series I Q1FL Q2FL Q2FL Q2FL Q1FA Room Temp. Q1FA Series II Q1FA Q2FA Q2FA Q2FA µm, FAƒ 19.5 µm. Fig. 1 Fig. 2 ƒ SEM XRD z ùkü. Fig. 1(a),(b), w j» ³ew y ƒ. Fig. 2 XRD z, quartz y, muscovite. Fig. 1(c) v x x ƒ š, ³ ƒ w j»ƒ ³ew w ƒ. w j» sp geopolymeric k œ w» w. Fig. 2(c) v quartz mullite, swwš XRD pattern mw y w ƒ Geopolymeric k Geopolymeric k Table 2 w. Fig. 3 Table 2 w w k œ ùkü. ƒƒ w e w z, k yw» (5 L) ü 3 60 rpm/min yww. y w Table 2 L/S(Liquid/Solid) ³ ƒw z, 1 ³ w yww. y w» 3 x j (50 mm 50 mm 50 mm) w z, 1 ƒ w ü»s w r w. r 25 o C, 100% w 1 w z kxw 3, 7, 28 r d w r d r g 3 e w geopolymerization k z w XRD w. XRD(X-ray diffractometer; PHILIPS XPERT-PRO) CuKα w 10 o ~80 o d w. Geopolymeric k SEM (Scanning Electrion Microscope; LEO 1420 VP) w w. 3. š L/S y(series I) v ƒ y(series II), 2ƒ geopolymeric Fig. 3. Experimental procedure. 45«7y(2008)

4 398 Áy Á½ Table 3. Compressive Strengths of Geopolymeric Mortars Series I Series II Compressive Strength (MPa) 3day 7day 28day Q1FL Q1FL Q1FL Q2FL Q2FL Q2FL Q1FA Q1FA Q1FA Q2FA Q2FA Q2FA k w. geopolymeric k d Table 3 w. y v v 10 wt%, y v ³ (Q1, Q2) 90 wt% š w L/S y w geopolymeric k p L/S ƒw w. CŸ (Q1) KŸ (Q2) p w w š š, x w w ùkü. p L/S ƒw ƒ w geopolymeric k x n w yw ü»sƒ w e y ƒ û» ƒ. L/S 0.3 yw collodial solution w xk», j w p» w». 0.2 L/S û» y v ƒ k L/S w w v ƒ. Q1 Q2 w p w w ùkü l ³ geopolymeric k e w û ƒ. wr, L/S ³ v yw w x ƒ w ƒ ùkü. p L/S 0.2. ù geopolymeric k û. v ƒ ƒw w ww x v ƒ y k L/S 0.25 ƒw w. Table 3 Series II L/S 0.25 ƒw ³ v ƒ y w geopolymeric k w, w d ùkü. CŸ ³ v 20~40 wt% ƒw w geopolymeric k v 40 wt% ƒ 18.7 MPa ùkü. w ƒ w. K Ÿ ³ v ƒ w p 30 wt% ƒ 20.4 MPa xw. Fig. 4 v, ³ geopolymeric k XRD z ùkü. v quartz mulliteƒ vj, ³ w vj quartz ƒ. w ³ 2 v ƒw r XRD z ql ƒ quartz vjƒ w Fig. 4. XRD patterns of fly ash based geopolymeric mortar; (a) low grade silica mineral of C Mine, (b) low grade silica mineral of K Mine. w wz

5 Fig. 5. XRD patterns of fly ash based geopolymer mortar cured in a oven at 25 for 3, 7, 28days. ƒ, mullite muscovite vjƒ û y w. w v ƒ r 2θ o 20 ~ 35 ùkü halo pattern, geopolymer aluminosilicate gel X- z p 2θ 20 ~ 35 v ƒ e y o y e aluminosilicate gel w ƒ. v ƒ 10-13) 10 wt% 30 wt% ƒw halo pattern ƒ w w y w ƒ. v ƒ 30 wt% 40 wt% ƒ k 30 o calcite vj y w ƒ. w calcite vj š e w v ü w 14.7 wt% CaOƒ e w ³ y w Fly Ash s k p 399 z, œ» CO 2 w ƒ. m sp p x 14,15) C-S-H ù Ca(OH) 2» w, C-S-H gel w w w {w. w calcium silicate hydrate calcium aluminium hydrate. v w geopolymeric k v ³ quartz, mullite, muscovite calcite aluminosilicate gel ùkû y w ƒ. 16) Fig. 5 K Ÿ ³ v 40 wt% ƒw geopolymeric k XRD z y ùkü. ƒ XRD z q l w ƒ. w calcite vj 3 l y w ƒ, XRD peak y, w. 2θ o 20 ~ 35 halo pattern 3 r w ù, 28 r y XRD peak mw y w ƒ. ƒw rü e w š, w mw aluminosilicate gel x w» š ƒ. ü Si-Où Al-O œ w OH w q Si Al k, k Naù K, Ca w w geopolymer x w ü geopolymeric matrix ƒw. 11) Fig. 6. SEM Photographs of fly ash based geopolymer mortar; (a) Q1FA-10, (b) Q1FA «7y(2008)

6 400 Áy Á½ Fig. 6 L/S 0.25 š w w, v 10 wt% 40 wt% ƒw w geopolymeric k 28 z, SEM w ùkü. SEM Q1FA-10 ü t»œ wš š, v ƒ û» v y w ƒ. ù Fig. 6 Q1FA-40 ü v x y w ƒ. w ³ matrix x wš š. w xk matrix w 10-12,17) aluminosilicate q wš, ew ƒ. Q1FA-40 t Q1FA-10 w e w x wš ƒ. v ƒ ³ wš ü x w» t e y ƒ ƒw q. 4. v y v w geopolymeric k geopolymer technique w w w. L/S û geopolymeric k ƒ w, ³ w v ey r ƒ. C ³ Ÿ ³ w r L/S = 0.25 v 40 wt% ƒw 18.7 MPa ƒ w, K ³ Ÿ ³ w r ƒ L/S = 0.25 v 30 wt% ƒw 20.4 MPa. w SEM geopolymeric k ü aluminosilicate gel d v t w. XRD, geopolymeric k aluminosilicate gel calcite quartz y w. Acknowledgment œ» (No.2006-R-RU11-P ) w,. REFERENCES 1. J. Davidovits, Geopolymers and Geopolymeric Materials, J. Therm. Anal., (1989). 2. J. Davidovits, Inorganic Polymeric New Materials, J. Therm. Anal., (1991). 3. W.K. Lee, S. G. Son, S. Y. Hong, J. H. Lee, E. Z. Park, and Y. D. Kim, Preparation and Its Characteristics of Inorganic Binder with MSWI Bottom Ash, J. Kor. Soc. Waste Mange., (2008). 4. Z. Yunsheng, S. Wei, C. Qianli, and C. Lin, Synthesis and Heavy Metal Immobilization Behaviors of Slag based Geopolymer, J. Hazard. Mater., (2006). 5. Sindhunata, A Conceptual Model of Geopolymerisation, PhD Thesis, Department of Chemical and Biomolecular Engineering, The University of Melbourne, P. Duxson, J.L Provis, G.C. Lukey, and J.S.J. van Deventer, The Role of Inorganic Polymer Technology in the Development of Green Concrete, Cem. Concr. Res., (2007). 7. K. Ikeda, Consolidation of Mineral Powders by the Geopolymer Binder Technique for Materials Use, Shigento-Sozai, (1998). 8. K. Ikeda and Y. Nakamura, Consolidation of Quartz Powder by the Geopolymer Technique, J. Kor. Ceram. Soc., 6 [2]G (2000). 9. D. Feng, A. Mikuni, Y. Hirano, R. Komatsu, and K. Ikeda, Preparation of Geopolymeric materials from Fly Ash Filler by Steam Curing with Special Reference to Binder Products, J. Ceram. Soc. Japan, (2005). 10. M. Criado, A. Palomo, and A. Fernandez-Jimenez, Alkali Activation of Fly Ashes. Part 1: Effect of Curing Conditions on the Carbonation of the Reaction Products, Fuel, (2005). 11. A. Palomo, M.W.Grutzeck, and M.T.Blanco, Alkali-Activated Fly Ashes-A Cement for the Future, Cem. Concr, Res., (1999). 12. M. Criado, A. Fernandez-Jimenez, A.G. de la Torre, M.A.G. Aranda, and A. Palomo, An XRD Study of the Effect of the SiO 2 /Na 2 O Ratio on the Alkali Activation of Fly Ash, Cem. Concr. Res., (2007). 13. D. Panias, I. P. Giannopoulou, and T. Perraki, Effect of Synthesis Parameters on the mechanical Properties of Fly Ash-Based Geopolymers, Colloids Sur. A (2007). 14. W. Z. Choi and E. K. Park, Study on CaCO 3 Preparation from MSWI Fly Ash, J. Kor. Inst. Resource Recycling, (2006). 15. M. Palacios and F. Puertas Effect of Shrinkage-Reducing Admixtures on the Properties of Alkali-Activated Slag Mortars and Pastes, Cem. Concr. Res., (2007). 16. C.K.Yip, G.C.Lukey, and J.S.J. van Deventer, The Coexistence of Geopolymeric gel and Calcium Silicate Hydrate at the Early Stage of Alkaline Activation, Com. Concr. Res., (2005). 17. S.S. Park, H. Y. Kang, S.H. Han, and H.B. Kang, Effects of NaOH and Na 2 SiO 3 9H 2 O Addition on Strength Development of Class F Fly Ash-Mortar, J. Institute structural maintenance inspection, (2005). w wz