Journal of Materials Science

, Volume 41, Issue 5, pp 1579–1584 | Cite as

Solidification of coal fly ash using hydrothermal processing method

  • Z. Jing
  • N. Matsuoka
  • F. Jin
  • N. Yamasaki
  • K. Suzuki
  • T. Hashida


Solidification of Coal Fly-ash (CFA) has been carried out using a hydrothermal processing method. In the hydrothermal processing, the CFA was first compacted in a mold at 20 - 50 MPa, and then hydrothermally cured in an autoclave. The hydrothermal curing was performed at 150 – 250°C for 15 – 60 h. The experimental results showed that NaOH solution, Ca(OH)2 content, compaction pressure, autoclave curing temperature and time significantly affected the strength of solidified bodies. The most important strength-producing constituent in the solidified bodies produced with CFA was tobermorite, or tobermorite-like calcium silicate hydrate. When the CaO/SiO2 ratio of the starting material was close to 0.83, tobermorite readily formed and the formed tobermorite enhanced the strength of solidified bodies. The tensile strength determined by the Brazilian test reached more than 10 MPa under the hydrothermal processing. As such, the hydrothermal processing method may provide a high potential for recycling CFA on a large scale.


Hydrate Silicate Mold Tensile Strength Compaction 
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Copyright information

© Springer Science + Business Media, Inc. 2006

Authors and Affiliations

  • Z. Jing
    • 1
  • N. Matsuoka
    • 1
  • F. Jin
    • 1
  • N. Yamasaki
    • 1
  • K. Suzuki
    • 2
  • T. Hashida
    • 3
  1. 1.Graduate School of Environmental StudiesTohoku UniversitySendaiJapan
  2. 2.Kochi Hydrothermal Institute of Science and TechnologyKochiJapan
  3. 3.Fracture and Reliability Research InstituteTohoku UniversitySendaiJapan

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