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1 Jurnal f the Krean Ceramic Sciety Vl. 48, N. 1, pp. 80~85, DOI: /KCERS Effect f HF Treatment n the Crystallizatin Behavir f the Glass Cntaining Cal Bttm Ashes Sinae J and Seunggu Kang Department f Materials Engineering, Kynggi University, Suwn , Krea (Received December 30, 2010; Revised January 15, 2011; Accepted January 17, 2011) k ƒ sw y p e HF z üá» w œw ( ; ; ) ABSTRACT The crystallizatin behavir and micrstructural change f the glass-ceramics were analyzed as a functin f cncentratin and etching time f the HF slutin in rder t enhance the degree f crystallinity induced by hetergeneus nucleatin f glass f bttm ash cntaining 15 wt% Li 2 O. The nucleatin site seemed t be generated where the Si in was eluted. The main crystal phases in the glass-ceramics fabricated in this study were β-spdumene and Li 2 SiO 3. The specimens etched with HF f 0.5 vl% within 0~60 secnds shwed increased crystalline peak intensities in XRD pattern with etching time cmpared t n-etched ne. Als the crystal size and crystal ccupancy in the glass matrix bserved by SEM were increased with etching time. Fr the glass-ceramics etched with 1.0 and 2.0 vl% HF slutin, the etching time ver 10 s was nt effective t increase the crystallinity. Frm this study, it was fund that the glass-ceramics with the higher crystallinity culd be btained by HF-etching fllwed by heat treatment prcess, even thugh the nucleating agent r 2-stages thermal treatment prcess were nt used. Key wrds : Glass, HF etching, Glass-ceramics, Nucleatin site, Cal bttm ash 1. ü y k 6 m, 1) ey w» w ƒƒeƒ t w w w ƒ y w š. 2) k k ƒ w š ³ w w x w y. w m yw w m w ƒ y š, 3,4) w y j ù w y (glass-ceramics) w w š. 5) k l y w t yƒ ù š. 2) t yƒ r m y ƒ û,» ƒ û Crrespnding authr : Seunggu Kang sgkang@kgu.ac.kr Tel : Fax : wš ü y(bulk crystallizatin) w» w š. ƒ wx ƒw y w w. w wx w w 2 (2-stages) š. 6) mw wx (T N ) (T P ) d w, û T N w wx jš z T P w x w j. k w w, wx ƒw ù 2 w š, r HF w wx (site) ƒ k r y. w k w ƒw û š, HF y p wš w HF ƒ y e w š w. 80

2 k ƒ sw y p e HF z 81 Table 1. Weight Percent f Cnstitutinal Oxides f Calcined Cal Bttm Ash and Glass Specimen (wt%) Oxide grups Acids Neutrals Bases Others Raw Materials SiO 2 ZrO 2 TiO 2 Al 2 O 3 Fe 2 O 3 K 2 O Na 2 O MgO CaO MnO Li 2 O P 2 O 5 Calcined bttm ash Glass x XRF mw k (cal bttm ash) y w Table 1 ùkü. k k ƒ 18 wt%ƒ w w» w 1000 C» 3 w w. w k 45 µm j» ü z Li 2 O 15 wt% yww g w 24 w. yw ù ƒ 1350 C» 20 min w z ƒ,, ƒ ƒ 1cm š T g (glass transitin temperature) 10 C 516 C ƒ w þƒ w w w. T g DTA mw x d w. wx (site)» w 0.5 ~ 2.0 vl% HF 0~60 ü r e(etching)w. r 45 µm w z DTA(Differential Thermal Analysis; STA 409 C/CD, Netzsch C.) mw p w. DTA l l l r y j» w w. r y w» w XRD(Xray Diffractmeter; D/MAX-C, Rigaku C.), w w FESEM(Field Emissin Scanning Electrn Micrscpe;cSM-6500F, JEOL C.) w. HF e w» w ICP-AES (Inductive Cupled Plasma- Atmic Emissin Spectrphtmeter, ICP 2070, LEEMAN LABS, Inc.) w x ww. 3. š w k 15 wt% Li 2 O ƒw y r w XRD Fig. 1 ùkü. Fig. 1 w k quartz(sio 2 ) mullite(3al 2 O 3 2SiO 2 ). k mullite k SiO 2 Al 2 O 3 w x ƒ. ƒ w» w /» Fig. 1. XRD patterns f (a) calcined cal bttm ash and (b) glass cntaining 85 wt% cal bttm ash and 15 wt% Li 2 O. Table 2. The Acid/base Oxides Rati and Basicity Calculated Based n Ml Fractin f Calcined Cal Bttm Ash and Glass Specimen Acid/base xides rati* Basicity Calcined bttm ash Glass * Acid/base xides rati = (RO 2 )/(R 2 O+RO) Basicity = (R 2 O+RO)/(SiO 2 +Al 2 O 3 +Fe 2 O 3 +TiO 2 ) y» w Table 2 ùkü. Andrews v p(frit)ƒ» w /» y 1~3 w frit rule w. k /» y 7) frit rule ù j» ƒ. Li 2 O 15 wt% ƒw /» y 1.47 frit rule ƒ, x w d. w» (basicity)ƒ ƒ š,». 8) Basicity = (R 2 O + RO)/(SiO 2 +Al 2 O 3 +Fe 2 O 3 +TiO 2 )» R= «1y(2011)

3 82 üá Fig. 2. DTA curve fr glass specimen measured at heating rates f 20 Cmin 1. üy d w» ƒ 0.01 w» w ( )ƒ 50 C û š. k» 0.07 m 9) 0.03~0.06 ƒà. ù Li 2 O 15 wt% ƒw» 0.52 j š, ƒ. k 1600 C ù Li 2 O 15 wt% ƒw 1350 C š, w û x w. Li 2 O 15 wt% ƒw r XRD (Fig. 1) vjƒ x ùkù x (nn-crystalline) ql ùkü. l w k y w. Li 2 Oƒ 15 wt% ƒ wš þ k r w DTA x ww Fig. 2 ùkü. 506 C vj (T g ) ùkü š, 668 C vj yƒ ù w. r y j» w vj 668 Cƒ óù (732 C) 5 ww. DTA w» y kinetics w. (1) txw Jhnsn- Mehl- Avrami(JMA). 10,11) n lnα( 1 x) kt =» α DTA d ƒ š, x t (1) Fig. 3. XRD peak patterns f glass-ceramics sintered at 732 C/ 5 hrs as a functin f varius HF-etching times at 0.5 vl% HF slutin. Fig. 4. XRD peak patterns f glass-ceramics sintered at 732 C/ 5 hrs as a functin f varius HF-etching times at 1.0 vl% HF slutin. y v, n (Avrami). n 1 ƒ¾ t yƒ wš 3~4 ü y w š. 10) Chi k n 1.97 w, l ü y t yƒ w š šw. 2) r ü y» w r w (site) š HF ww., ³ w (hetergeneus nucleatin) w yƒ w. w r w» 0.5, 1.0 š 2.0 vl% HF 10~60 e(etching)w. w wz

4 석탄바닥재가 포함된 유리의 결정화 특성에 미치는 HF 처리 효과 83 한편, 1.0 vl% HF에 10초 처리된 시편들의 경우 (Fig. 4) 전혀 처리하지 않은 경우에 비해 β-spdumene 피크가 증 가되었으나, 60초 이상이 되면 β-spdumene 및 Li SiO 결정피크 강도가 다시 줄어드는 것으로 나타났다. 2.0 vl% HF 용액에 10초 처리된 시편(Fig. 5) 역시 HF 처리되지 않은 경우에 비하여 결정상 피크들의 강도가 증가되었다. 그러나 처리 시간을 60초로 늘리면 오히려 β-spdumene 및 Li SiO 의 주피크 강도가 크게 줄어드는 것으로 나타 났다. 이처럼 1.0 내지 2.0 vl% HF 용액으로 처리한 경 우 60초 동안 에칭한 것이 10초에 비해 오히려 결정화도 가 낮아지는 이유에 대한 정량적 해석은 추가연구가 필 요하다고 생각된다. Fig. 6은 여러 조건으로 HF 처리한 유리를 결정화시킨 시편의 미세구조 관찰 사진이다. 먼저 HF 처리를 전혀 하 지 않은 결정화 유리의 미세구조를 보면, 0.1 µm 크기의 결정입자들이 생성되었으나 유리 모상(martix)에서의 결정 점유율은 크지 않은 것을 알 수 있다. 농도에 관계없이 HF로 10초간 처리된 시편들의 모상 내 결정 점유율이 HF 처리되지 않은 시편에 비해 높아진 것을 관찰할 수 있다. 또한 0.5 vl% HF 용액으로 처리된 경우, 처리시간을 60 초로 늘리면 10초간 처리된 시편에 비해 결정 점유율이 매우 높아졌다. 1.0 vl% HF 용액으로 10초간 처리된 시편의 미세구조 는 처리하지 않은 것에 비해 결정입자의 크기가 증가하 2 2 Fig. 5. XRD peak patterns f glass-ceramics sintered at 732C/5 h as a functin f varius HF-etching times at 2.0 vl% HF slutin. Figs. 3~5는 유리시편을 농도 및 처리시간을 변수로 HF 용액으로 에칭한 후 열처리하여 결정화된 시편들의 XRD 측정결과이다. 0.5 vl%의 HF로 처리된 시편의 경우(Fig. 3) 유지시간이 길어질수록 결정화가 증가하는 것을 볼 수 있 었다. 즉, 0.5 vl% HF에 60초간 처리된 시편의 경우, 처 리되지 않은 시편에 비해 β-spdumene 및 Li SiO 결정상 피크 강도가 더 증가된 것을 볼 수 있다. 2 Fig Micrstructures f glass-ceramics bserved by SEM as a functin f treatment time and cncentratin f HF slutin. 제 48 권 제1호(2011)

5 84 üá Table 3. The Cncentratin f Catins Eluted frm the Glass by 1.0 vl% HF Slutin fr 30 s (ppm) Si Ca Al Li Fe š ü ƒ. ù 60 j»ƒ ƒ ¼ w ù. w w 2.0 vl% HF r ùkû. 60 r 10 w ƒw. r ü ƒ 0.5 vl% HF 60., HF 10 w ƒ, 60 ƒ z 0.5 vl% ùkû. HF ƒ w û Figs. 3~5 XRD vj ew. r 1.0 vl% HF 30 ew ICP ww Table 3 ùkü. ƒ Si 78.8 ppm ml%ƒ w Al 1.03 ppm. Si ƒ r HF j F - Si w(nuclephilic) k H + O (electrphilic) g òsi-o-siò w ñ». 12,13) ü Al mle» Si 50% (Table 1) ù Si w. 4 Al òal-o-siò w òsi-o-siò w Al e w w. w ICP l HF w Si ù wx ƒ. mw 0.5~2.0 vl% HF 10~60 w 15 wt% Li 2 O w w w XRD l ü yƒ w w. p 0.5 vl% HF 60 w r, wx ù 2 œ w š k HF e w w y ƒ y (glass-ceramics) w y w. w wz 4. k 15 wt% Li 2 O yww û w, 0.5~ 2.0 vl% HF 10~60 ew wx (site) ƒ k r y. HF e ƒ Si l wx Si ù e. r β-spdumene Li 2 SiO 3ƒ. 0.5 vl% HF r ¼ β-spdumene Li 2 SiO 3 vj ƒ ƒ w. wr, vl% HF 10 r x w w β-spdumene v jƒ ƒ ù, 60 β-spdumene Li 2 SiO 3 vj ƒ., HF w y 0.1 µm j» ù (martix) j. HF 10 r ü HF r w. 0.5 vl% HF, r w ù, vl% HF r 60. mw 0.5~2.0 vl% HF 10~60 w 15 wt% Li 2 O w w wx ù 2 œ w š HF e w w y ƒ y (glass-ceramics) w y w. REFERENCES 1. Krea Electric Pwer Crpratin, The Mnthly Reprt n Majr Electric Pwer Statistics, Krea, N. 334, C. P. Chi and S. G. Kang, Crystallizatin Behavir at Nucleatin Sites n the Surfaces f Vitreus Materials Laded with Cal Bttm Ash, J. Kr. Phys. Sc., 54 [3] (2009). 3. K. D. Kim and S. G. Kang, Manufacturing Artificial Lightweight Aggregates Using Cal Bttm Ash and Clay, J. Kr. Cryst. Grw. and Cryst. Tech., 17 [6] (2007). 4. J. T. Sng, S. D. Yun, D. W. Ryu, and K. S. Han, Manufacture and Prperties f Cal Fly Ash-Clay Bdy, J. Kr. Ceram. Sc., 33 [7] (1996). 5. S. J. Jang and S. G. Kang, Micrstructural Analysis f Hybrid Materials Cmpsed f Nepheline Crystals and a Glass Matrix Fabricated frm Cal Bttm Ash, J. Ceram. Pr. Res., 10 [1] (2009).

6 k ƒ sw y p e HF z S. N. J and S. G. Kang, Study n the Glass-Ceramics Cntaining Cal Bttm Ashes Fabricated by 2-Stages Thermal Treatment Methd, J. Kr. Cryst. Grw. and Cryst. Tech., 20 [6] (2010). 7. A. I. Andrews, Ceramic Tests and Calculatins, pp.80-1, Jhn Wiley & Sns Inc., New Yrk, S. Vargas, F. J. Franadsen, and K. D. Jhansen, Rhelgical Prperties f High-Temperature Melts f Cal Ashes and Other Silicates, Prg. in Ener. & Cmb. Sci., (2001). 9. K. S. Kim and S. G. Kang, The Cntrl f Liquid Phase Behavir During Sintering f Clay/EAF Dust Bdies, J. Kr. Cryst. Grw. and Cryst. Tech., 15 [2] (2005). 10. W. A. Jhnsn and K. F. Mehl, Reactin Kinetics in Prcess f Nucleatin and Grwth, Trans. AIME., (1939). 11. M. Avrami, Granulatin, Phase Change and Micrstructure Kinetics f Phase Change, J. Chem. Phys., (1941). 12. W. H. Kang, Glasses, in Kr., Cheng Mn Gak Publishers, Paju, Krea, J. H. Eum, K. Y. Chi, S. Nahm, and K. Chi, Texturing f Multi-Crystalline Silicn Using Istrpic Etching Slutin, J. Kr. Ceram. Sc., 46 [6] (2009). 48«1y(2011)