Microstructural observation of artificial aggregates at various sintering atmospheres

소성 분위기에 따른 인공골재의 미세구조 관찰

  • Park, Ji-Yun (School of Advanced Industrial Engineering, Department of Materials Science & Engineering, Kyonggi University) ;
  • Kim, Yoo-Taek (School of Advanced Industrial Engineering, Department of Materials Science & Engineering, Kyonggi University)
  • 박지윤 (경기대학교 첨단산업공학부 신소재공학) ;
  • 김유택 (경기대학교 첨단산업공학부 신소재공학)
  • Published : 2006.04.30

Abstract

The aggregates made of clay, carbon and $Fe_2O_3$ were prepared to investigate the mechanism of black core formation and the property differences at various sintering atmospheres. The aggregates were sintered at oxidized, neutralized and reduced atmospheres. The specific gravity, absorption rate, percent of black core area were measured at various compositions and sintering atmospheres. The aggregates sintered at oxidized atmosphere showed clear border between shell and black core area. Hence, the aggregates sintered at reduced and neutralized atmospheres showed only black core area in the cross-section of the aggregates. The specific gravity of the aggregates sintered at reduced atmosphere increased with increasing carbon contents and that was the lowest of all aggregates sintered at various atmospheres. Adsorption rate increased with increasing carbon contents at all atmospheres.

소성 분위기를 변화시켜 골재를 제조할 때 골재의 중앙에 만들어지는 블랙코어(black core) 형성정도의 차이와 골재 물성의 차이점을 알아보기 위해 적점토, 탄소(carbon), 산화철($Fe_2O_3$)이 혼합된 직경 10mm 구형골재를 조성별로 산화분위기, 중성분위기, 환원분위기에서 각각 소성시키고 각각의 비중, 흡수율, 블랙코어 면적비(%)를 측정하고 비교하였다. 산화분위기에서 소성시킨 골재는 껍질(shell)과 블랙코어가 뚜렷하게 구분되는 반면 중성 및 환원분위기에서 소성한 시편에서는 시편의 단면전체에 블랙코어가 형성되었다. 산화분위기와 중성분위기와는 달리 환원분위기에서 소성된 시편에서는 탄소첨가량이 증가할수록 비중이 증가했으며, 전반적인 비중은 가장 낮았다. 흡수율은 모든 분위기에서 탄소첨가량이 증가할수록 증가하는 경향을 보였다.

Keywords

References

  1. A. Escardino, A. Barba, A. Blasco and F. Negre, 'Oxidation of black core during firing of ceramic ware: 4 Relationship between effective diffusity of oxygen through oxidised layer and properties characterising its porous structure', British Ceramic Transactions 94(3) (1995)
  2. Jon Pacini, 'Bloating and black coring', Laguna Clay Co, January (1999)
  3. F. Negre, A. Barba, J.L. Amoros and A. Escarkino, 'Oxidation of black core during the firing of ceramic ware-2. process kinetics', Br. Ceram. Trans. J. 91 (1992) 5
  4. Y.J. Joo and M. S. Oh, 'Unburnt carbon combustion in the production of light weight sintered fly ash', Proceeding of KSEE conference (2002) 91
  5. A. Barba, F. Negre, M.J. Orts and A. Escardino, 'Oxidation of black core during the firing of ceramic ware-3. influedce of the thickness of the piece ane the composition of the black core', Br. Ceram. Trans. J. 91 (1992) 36
  6. S.S. Cava, J.A. Cerri, C.A. Paskocimas, E. Longo, J.A. Varela, T. Mendoca and C.G. Herter, 'Supressing blackcoring in single-fire ceramic tiles by controlling klin atmosphere', Ceramic tile quality (1998) 15
  7. Alexader Karamanov, Paola Pisciella, Carlo Cantalini and Mario Pelino, 'Influence of $Fe_{3+}/Fe_{2+}$ ration on the crystallization of iron-rich classes made with industrial wastes', J. Am. Ceram. Soc. 83(12) (2000) 53 https://doi.org/10.1111/j.1151-2916.2000.tb01147.x