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Influence of red mud additive on lightening of artificial aggregates containing coal bottom ash

석탄바닥재가 포함된 인공골재의 경량화에 미치는 적니 영향

  • Kang, Min-A (Department of Materials Engineering, Kyonggi University) ;
  • Kang, Seung-Gu (Department of Materials Engineering, Kyonggi University)
  • 강민아 (경기대학교 신소재공학과) ;
  • 강승구 (경기대학교 신소재공학과)
  • Received : 2010.12.01
  • Accepted : 2011.02.07
  • Published : 2011.02.28

Abstract

The artificial aggregates (AAs) composing of 2 wastes, coal bottom ash and dredged soil (7 : 3, weight ratio) were fabricated as a function of red mud contents,0~30 wt% using direct sintering method at $1050{\sim}1250^{\circ}C$ for 10 min, and those physical properties were evaluated. Especially, in order to analyze the red mud addition effect on the bloating phenomenon of AAs manufactured, the specific gravity and water absorption were measured and studied linked with the microstructural observation results. The lightening of AAs was enhanced due to increased bloating with increasing temperature and red mud contents. The AAS sintered at $1050{\sim}1150^{\circ}C$ showed well-developed black-coring structure, but for the specimens containing red mud sintered over $1200^{\circ}C$ generated excessive liquid and gas caused by reduction of $Fe_2O_3$, thus the black-coring part was gradually burst open out of shell of AAs. Particularly, all specimens containing 30 wt% red mud was burst up when sintered over $1100^{\circ}C$. The AAs containing no red mud sintered at $1200^{\circ}C$ had a specific gravity of about 1.2 and those containing 20 wt% had below 1.0 which are characters of lightweight aggregate.

폐기물인 석탄바닥재와 준설토가 70 : 30(wt%)으로 혼합된 배치분말에 적니를 0~30 wt% 첨가하고 $1050{\sim}1250^{\circ}C$에서 10분 직화 소성하여 인공골재를 제조하고 그 물성을 평가하였다. 특히 인공골재의 발포특성에 미치는 적니 첨가량 효과를 분석하기 위해 비중 및 흡수율을 측정하고, 그 결과를 미세구조 결과와 연계하여 고찰하였다. 제조된 인공골재는 소성온도 및 적니 첨가량이 증가할수록 발포성이 향상되어 경량화 되는 특징을 나타내었다. $1050{\sim}1150^{\circ}C$ 범위로 소결된 대부분의 인공골재는 잘 형성된 블랙코어 구조를 가졌으나, 적니가 첨가되고 $1200^{\circ}C$ 이상으로 소결된 시편들은 $Fe_2O_3$의 환원에 의한 과량의 가스 방출 및 액상 형성으로 인하여 블랙코어 부분이 시편 표피를 뚫고 나오는 현상이 나타났다. 특히 적니 30 wt%를 함유한 시편은 $1100^{\circ}C$ 이상으로 소결하면 폭발되어 여러 조각으로 흩어졌다. 본 연구에서 $1200^{\circ}C$에서 소결된 시편의 부피비중은 적니가 첨가되지 않은 것은 1.2, 적니가 20 wt% 첨가된 것은 1.0 이하의 경량골재 특성을 나타내었다.

Keywords

Acknowledgement

Supported by : 한국연구재단

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