Geomodification of combustion residues for mineralogical immobilization of heavy metals and accelerated conversion to natural soils

2016 Fiscal Year Final Research Report

• Project/Area Number: 26550059
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental engineering and reduction of environmental burden
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Takahashi Fumitake 東京工業大学, 環境・社会理工学院, 准教授 (00414376)
• Research Collaborator: KITAMURA Hiroki 東京工業大学, 大学院総合理工学研究科, 院生 ; Dahlan Astryd Viandila 東京工業大学, 大学院総合理工学研究科, 院生
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 焼却飛灰 / 重金属不溶化 / 土壌還元 / 鉱物学的表面修飾 / 鉱物生成

Outline of Final Research Achievements

In this study, mineralogical immobilization of toxic elements by secondary mineral formation was investigated for municipal solid waste incineration (MSWI) fly ash and coal fly ash. In the case of MSWI fly ash, soluble elements and heavy metals were immobilized by gypsum and other neoformed minerals. However, heavy metal incorporation to secondary mineral structure like ettringite was not verified. In the case of coal fly ash, toxic elements like fluorine were immobilized by apatite formation. When MSWI fly ash particles were analyzed at micro-scale level, these were found to have complex structures inside each particle body. In addition, MSWI fly ash particles had large heterogeneity not only inside their body but also among fly ash particles although they have been regarded as fine and homogeneous materials. It suggests that successful formation of target secondary minerals might have limited effect on heavy metal immobilization owing to fly ash heterogeneity.

Free Research Field

環境工学