Korean Journal of Mineralogy and Petrology (광물과 암석)

The Petrological Society of Korea & The Mineralogical Society of Korea (한국암석학회 & 한국광물학회)
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Manufacture of non-sintered cement solidifier using clay, waste soil and blast furnace slag as solidifying agents: Mineralogical investigation

점토, 폐토양 및 고로슬래그를 고화재로 이용한 비소성 시멘트 고화체 제조: 광물학적 고찰

  • Jeon, Ji-Hun (Department of Geology and Research Institute of Natural Science (RINS), Gyeongsang National University (GNU)) ;
  • Lee, Jong-Hwan (Department of Geology and Research Institute of Natural Science (RINS), Gyeongsang National University (GNU)) ;
  • Lee, Woo-Chun (Department of Geology and Research Institute of Natural Science (RINS), Gyeongsang National University (GNU)) ;
  • Lee, Sang-Woo (Department of Geology and Research Institute of Natural Science (RINS), Gyeongsang National University (GNU)) ;
  • Kim, Soon-Oh (Department of Geology and Research Institute of Natural Science (RINS), Gyeongsang National University (GNU))
  • 전지훈 (경상국립대학교 지질과학과 및 기초과학연구소(RINS)) ;
  • 이종환 (경상국립대학교 지질과학과 및 기초과학연구소(RINS)) ;
  • 이우춘 (경상국립대학교 지질과학과 및 기초과학연구소(RINS)) ;
  • 이상우 (경상국립대학교 지질과학과 및 기초과학연구소(RINS)) ;
  • 김순오 (경상국립대학교 지질과학과 및 기초과학연구소(RINS))
  • Received : 2022.02.22
  • Accepted : 2022.03.08
  • Published : 2022.03.31
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Abstract

This study was conducted to evaluate the manufacturing process of non-sintered cement for the safe containment of radioactive waste using low level or ultra-low level radioactive waste soil generated from nuclear-decommissioning facilities, clay minerals, and blast furnace slag (BFS) as an industrial by-product recycling and to characterize the products using mineralogical and morphological analyses. A stepwise approach was used: (1) measuring properties of source materials (reactants), such as waste soil, clay minerals, and BFS, (2) manufacturing the non-sintered cement for the containment of radioactive waste using source materials and deducing the optimal mixing ratio of solidifying and adjusting agents, and (3) conducting mineralogical and morphological analyses of products from the hydration reactions of manufactured non-sintered cement solidifier (NSCS) containing waste concrete generated from nuclear-decommissioning facilities. The analytical results of NSCS using waste soil and clay minerals confirmed none of the hydration products, but calcium silicate (CSH) and ettringite were examined as hydration products in the case of using BFS. The compressive strength of NSCS manufactured with the optimum mixing ratio and using waste soil and clay minerals was 3 MPa after the 28-day curing period, and it was not satisfied with the acceptance criteria (3.44 MPa) for being brought in disposal sites. However, the compressive strength of NSCS using BFS was estimated to be satisfied with the acceptance criteria, despite manufacturing conditions, and it was maximized to 27 MPa at the optimal mixing ratio. The results indicate that the most relevant NSCS for the safe containment of radioactive waste can be manufactured using BFS as solidifying agent and using waste soil and clay minerals as adsorbents for radioactive nuclides.

본 연구는 원자력 시설 해체 시 발생되는 저준위 및 극저준위 폐토양, 점토와 산업부산물인 고로슬래그를 이용하여 방사성 폐기물을 안전하게 담지할 수 있는 비소성 시멘트의 제조 가능성을 평가하고 광물·형태학적 분석을 통하여 생성된 반응 물질에 대하여 고찰하였다. 본 연구에서는 (1) 폐토양, 점토 및 고로슬래그의 특성 분석, (2) 폐토양, 점토 및 고로슬래그를 고화재 및 성분조정제로 이용한 원전 해체 폐기물 담지를 위한 비소성 시멘트 제조 및 최적의 배합 비율 도출, (3) 제조된 비소성 시멘트 고화체의 수화반응 생성물질에 대하여 광물·형태학적 분석 등을 수행하였다. 비소성 시멘트 고화체의 광물·형태학적 분석 결과, 폐토양과 점토는 수화반응 생성물이 관측되지 않았으며, 고로슬래그의 경우 고화체의 강도를 발현시킬 수 있는 수화반응생성물질인 calcium silicate hydrate (CSH), 에트링가이트(ettringite)가 생성되는 것을 확인하였다. 폐토양, 점토를 고화재로 이용한 비소성 시멘트의 재령 28일 후 고화체는 최적의 배합 비율에서 약 3 MPa의 강도를 나타내 처분장 인수기준 압축강도인 3.44 MPa를 만족하지 못하는 것을 확인하였다. 그러나, 고로슬래그를 고화재로 이용한 비소성 시멘트는 모든 실험 조건에서 처분장 인수기준 압축강도를 만족하며, 최적의 배합 비율에서는 약 27 MPa로 높게 나타나는 것을 확인할 수 있었다. 이러한 결과를 통하여 비소성 시멘트 고화재로 고로슬래그, 방사성 핵종에 대한 흡착제 역할로 폐토양 및 점토를 이용한다면 방사성 폐기물 처분을 위한 최적의 비소성 시멘트를 제조할 수 있을 것으로 판단된다.

Keywords

Acknowledgement

본 연구는 국가연구개발 과제(한국에너지기술평가원) 에너지기술개발사업 지원을 받아 수행되었습니다(과제번호: 20201520300070).

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