Bahri Öteyaka, Bülent Yılmaz, Ali Uçar, İskender Işık, Ahmet Aydın

MİKRO SİLİKA MONOLİTİK MALZEME ÜRETİMİ

Bu çalışmada; Gözenekli malzeme olarak büyük bir endüstriyel öneme sahip, Silika bazlı aerojel üretiminde kullanılan sol-jel tekniğine alternatif olarak kaolenlerin asit liç’i ile mikro silika monolitik malzeme üretimi araştırılmıştır. Bu amaçla kaolenin özellikleri TG-DTA, XRD, FTIR ve SEM deneyleri ile incelenmiştir. Karakterizasyon sonuçlarına göre kaolen 800 oC sıcaklıkta metakaolen haline getirilmiştir. H2SO4 ve HCl’in reaktif olarak kullanıldığı asit liçinde kullanılan asidin türüne bağlı olarak zaman ve sıcaklık mikro silika monolitik malzeme üretiminde etkili faktörler olarak belirlenmiştir. Liç verimine bağlı olarak H2SO4, HCl’den zaman ve sıcaklık açısından daha iyi bir performans göstermesine rağmen H2SO4’den üretilen mikro silikalı malzemenin HCl den üretilene göre daha iri taneciklerden ve daha boşluklu yapılardan oluşması monolitik malzeme üretiminde HCl’nin daha uygun bir reaktif olabileceğini göstermektedir.

Anahtar Kelimeler:

Kaolen, monolitik malzeme, metakaolen, liç

THE PRODUCTION OF THE MICRO SILICA MONOLITHIC MATERIAL

In this study, the monolithic silica (micron size) is produced by the kaolin leaching method as alternative route to sol-gel method used in silica based aerojel production synthesis, as a porous materials has most important in industry. Kaolin was characterized by TG-DTA, XRD, FTIR and SEM. The results showed that kaolin was transformed to metakaolin at 800 oC. The type of acid, time and temperature during the production of the monolithic silica (micron size) are key factors associated with the reactive acids such as H2SO4 and HCl used in acid leaching method. Although, according to leaching efficiency, H2SO4 have better performance than HCl in terms of time and temperature, monolithic silica produced by H2SO4 has larger grain with high porosity than one produced by HCl, which indicates that HCl is better reactive than H2SO4

Keywords:

Kaolin, monolithic material, metakaolin, leaching,

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[1] Schmidt, M., Schwertfeger., F., “Applications For Silica Aerogel Products”. Journal of Non-Crystalline Solidsi, Vol. 225, pp. 364–368, 1998.
[2] Tsai, M. S., “The Study Of Formation Colloidal Silica Via Sodium Silicate” Materials Science and Engineering., Vol. 106, pp. 52–55, 2004.
[3] Douglas, M., Smith, A., Boes, M., and U., “Aerogel-Based Thermal Insulation” Journal of non-crystalline solids, Vol. 225, pp. 254-262, 1998. [ 4] Kuchta, L., “About The Synthesis And Thermal Stability Of Sio2-Aerogel”, Journal of thermal analysis, Vol. 46, pp. 515, 1996.
[5] Rettelbach, Th., Säuberlich, J., Korder, S., Fricke, J., “Thermal Conductivity Of Silica Aerogel Powders At Temperatures From 10 To 275K”, Journal of non-crystalline solids, Vol.186, pp. 278, 1995. 81 DPÜ Fen Bilimleri Dergisi Mikro Silika Monolitik Malzeme Üretimi Sayı 18, Nisan 2009 B.Öteyaka, B.Yılmaz, A.Uçar, İ.Işık, A.Aydın
[6] Deng, Z., Wang, J., Wu, A., Shen, J., Zhou, B., “High Strength SiO2 Aerogel İnsulation”, Journal of non-crystalline solids, Vol. 225, pp. 101, 1998.
[7] Grim, R.E., Clay Mineralogy, McGraw–Hill, London, 1953.
[8] Okada, K., Shimai, A., Takei, T., Hayashi, S., Yasumori, A., MacKenzie, K.J.D., “Preparation of microporous silica from metakaolinite by selective leaching method” Microporous. Mesoporous Materials, Vol. 21, pp 289, 1998.
[9] Temuujin, J., Burmaa, G., Amgalan, J., Okada, K., Jadambaa, Ts., MacKenzie, K.J.D., J. “Preparation of Porous Silica from Mechanically Activated Kaolinite” Porous Materials, Vol. 8, pp 233, 2001.
[10] Temuujin, J., Okada, K., MacKenzie, K.J.D., Ts. Jadambaa, Characterization of porous silica prepared from mechanically amorphized kaolinite by selective leaching Powder Technology , Vol. 121, pp 259, 2001.
[11] Gregg, S.J., Hill, K.F., Parker, T.W., “Grinding of kaolinite”. J. Applied Chemistry, Vol. 4, pp 666, 1954.
[12] Juhász, Z., Mechano-chemical activation of kaolin minerals. Acta Miner. Petrogr., Vol. 24, pp. 121, 1980.
[13] Aglietti, E.F., Porto Lopez, J.M., Pereira, E., Int. J. Miner. Processing, Vol. 16, pp 125, 1986.
[14] Vegliò, F., Recinella, M., Massacci, P., and Toro, L., “Sceening Tests, in the Study of Iron Oxide Leaching by Sucrose in Sulphuric Acid Solution, Using Statistical Methods”, Hydrometallurgy, Vol. 35, pp. 293-311, 1994.
[15] Panias, D., Taxiarchou, M., Douni, I., Paspaliaris, I., and Kontopoulos, A., “Thermodynamic Analysis of the Reactions of Iron Oxides: Dissolution in Oxalic Acid”, Canadian Metallurgical Quarterly, Vol. 35, pp. 363-373, 1996.
[16] Taxiarchou, M., Panias, D., Douni, I., Paspaliaris, I., and Kontopoulos, A.,; “Dissolution of Hematite in Acidic Oxalate Solutions”, Hydrometallurgy, Vol. 44, pp. 287-299, 1997.