제올라이트를 함유하는 소성점토의 제조

Fabrication of Calcined Clay Granule Comprising Zeolite

  • Kim, Byoung-Gon (Korea Institute of Geoscience and Mineral Resources (KIGAM), Minerals and Materials Processing Division) ;
  • Lee, Gye-Seung (Korea Institute of Geoscience and Mineral Resources (KIGAM), Minerals and Materials Processing Division) ;
  • Park, Chong-Lyuck (Korea Institute of Geoscience and Mineral Resources (KIGAM), Minerals and Materials Processing Division) ;
  • Jeon, Ho-Seok (Korea Institute of Geoscience and Mineral Resources (KIGAM), Minerals and Materials Processing Division) ;
  • Jeong, Soo-Bok (Korea Institute of Geoscience and Mineral Resources (KIGAM), Minerals and Materials Processing Division)
  • 투고 : 2008.03.15
  • 심사 : 2008.05.26
  • 발행 : 2008.08.28

초록

제올라이트는 높은 양이온교환능력(CEC)으로 인해 토양개량제의 사용이 고려되어 왔으나, 이에 관한 연구들의 대부분이 제올라이트를 합성하거나 천연제올라이트의 CEC를 증가시키는데 국한되어왔다. 실제로 제올라이트를 토양개량제로 사용하기 위해서는 유실되는 것을 방지하기 위한 과립화 (granulation or pelletizing)가 요구된다. 본 연구는 제올라이트를 토양개량제로 활용하기 위해 이를 포함하는 소성점토의 과립 (calcined clay granule)을 제조하고, 제올라이트의 특성을 최대로 활용할 수 있는 과립의 제조조건을 찾으려 하였다. 천연제올라이트, 고령토, 규석을 재료로 하여, pan granulator와 high shear mixer granulator의 두가지 과립기를 사용하여 과립을 제조하였다. 재료의 혼합비와 과립기의 회전속도 등을 조절하여 과립을 제조하였으며, 이를 $400\sim700^{\circ}C$범위에서 $100^{\circ}C$단위로 소성한 후 파쇄강도 (crushing strength), 기공분포 (pore distribution), CEC를 측정하였다. 토양개량제로 사용할 과립은 취급시에 요구되는 기본적인 강도뿐만 아니라 토양과 혼합된 후 답압(踏壓)에 견디기 위한 강도 또한 요구된다. 본 연구에서는 과립의 답압에 관한 저항성 평가방법을 마련하고, 마른 상태와 젖은 상태에서 과립의 저항성을 측정하였다. 과립기의 회전속도와 가열온도에 비례하여 답압에 대한 저항성은 증가하나 CEC는 감소하였다. Pan granulator는 $700^{\circ}C$이하의 가열에서 적절한 강도를 갖는 과립을 제조할 수 없었으나, high shear mixer granulator는 $500^{\circ}C$이상의 가열에 의해 답압에 저항성을 갖는 과립을 제조할 수 있었다.

This research tried to find out the optimum fabrication method of calcined clay granules comprising zeolite. Kaolin clay and natural zeolite powder were used as raw materials of calcined clay, and silica stone powder was used for controlling the porosity of the granules. The granulation was performed with two kinds of granulators: a pan granulator and a high-shear mixer granulator. Various granules were fabricated by the mixing ratios and the rotation speeds of the granulators, and were heated from 400 to $700^{\circ}C$ at $100^{\circ}C$ interval. The crushing strength, pore size distribution, and CEC of the granules were measured. The evaluation method for the resistance of granules to human treading was created and the tests were conducted at dry and wet conditions. The resistance and crushing strength improved in proportion to the rotation speed of the granulator and the heating temperature, but the CEC decreased. The pellet made by the pan granulator did not have the strength against treading upon heating to below $700^{\circ}C$, but the pellet made by the high-shear mixer granulator endured the treading test upon heating to over $500^{\circ}C$

키워드

참고문헌

  1. Bartake, P.P., Singh, D. N. 2007. A generalized methodology for determination of crushing strength of granular materials, Geotech Geol. Eng. 25: 203-213. https://doi.org/10.1007/s10706-006-9105-4
  2. Choi, J., Hur, N.-H. 1993. The study on the CEC increase and granulation of natural zeolite, 1 The effect of NaOH concentration and $Na_2O/Al_2O_3$ ratio, J. Korean Soc. Soil Sci. Fert.26(2): 67-71.
  3. Choi, J., Hur, N.-H., Lee, D.-H. 1993. The study on the CEC increase and granulation of natural zeolite, 2. Effects of temperature and time on the recrystallization of natural zeolite, J. Korean Soc. Soil Sci. Fert.26(3):151-154.
  4. Choi, J., Hur, N.-H. 1995. The study on the CEC increase and granulation of natural zeolite, 3. Effects of alkali treatment on the ammonium and potassium ion adsorption of natural zeolite, J. Korean Soc. Soil Sci. Fert.2(1):22-27.
  5. Jeong, G.-Y, Kim, S.-J. 1989. 7A phase in the Sancheong kaolin: 7 A-halloysite or kaolinite ?, J. Miner. Soc. Korea, 2(1):18-25.
  6. Jeong, G.-Y, Kim, S.-J., Kim, Y. -H., Cho, H. -G. 1995. Kaolinite formation by weathering of biotite in Sancheong kaolin, J. Miner. Soc. Korea, 8(1):37-45.
  7. Jin, S.-W. 1995. Neutralization for acid soils and calcium carbonate, J. Korean Prof. Eng. Association, 28(4):33-40.
  8. Kim, B.-G., Park, C.-L., Lee, G.-S., Jeon, H.-S. 2007. Preparation of PZSC pellets with triple layered structure for the use of growing media (I), KIGAM Bulletin, 12(1):20-34
  9. Kim, S.-J., Jeong, G.-Y., Lee, S.-J., Kwon, S.-K. 1989. Mineralogy of kaolin from Hadong-Sancheong area, Korea, J. Miner. Soc. Korea, 2(1):11-17.
  10. Knight, P.C., Johansen, A., Kristensen, H.G., Schaefer, T., Seville, J.P.K. 2000. An investigation of the effects on agglomeration of changing the speed of a mechanical mixer. Powder tech. 110: 204-209 https://doi.org/10.1016/S0032-5910(99)00259-4
  11. Ramaker, J.S. 2001. Fundamentals of the high-shear pelletisation process. Ph.D. Thesis, Rijksuniversiteit Groningen, The Netherlands:2-3
  12. Salman, A.D., Hounslow, M.J., Seille, J.P.K. 2007. Handbook of powder technology, vol. 11 Granulation, ELSEVIER, ISBN:978- 0-444-51871-2.
  13. Schaefer, T., Taagegaard, B. Thomsen, L.J., Kristensen, h.G. 1993. Melt pelletization in a high shear mixer. V. Effects of apparatus variables, Eur. J. Pharm. Sci. 1:133-141 https://doi.org/10.1016/0928-0987(93)90003-S
  14. Seo, G.-Y. 2000. Sustainment and improvement method for soil resources, Soil and fertilizer, ISSN 1226-2935, 4:3-16.