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Shiota K, Toda T, Oshita K, Fujimori T, Kaji H, Maeno A, Takaoka M. The effect of gas emission on the strength of composite products derived using alkali-activated municipal solid waste incineration fly ash/pyrophyllite-based systems. Chemosphere 2019; 228:513-520. [PMID: 31051354 DOI: 10.1016/j.chemosphere.2019.04.177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/15/2019] [Accepted: 04/23/2019] [Indexed: 06/09/2023]
Abstract
We explored the effects of gas emission by mixtures undergoing alkali-activation of municipal solid waste incineration fly ash (MSWIFA) and pyrophyllite (the mixtures included dehydrated pyrophyllite, MSWIFA, 14 mol/L aqueous sodium hydroxide, and sodium silicate; curing proceed at 105 °C for 24 h). We measured the compressive strengths of the derived solid composites. The causes of gas emission, and the physical and chemical properties of products created under controlled gas emission, were investigated. Hydrogen was emitted after mixing MSWIFA and alkali. The compressive strength of products prepared when gas emission was complete was 2-3.4-fold greater than that of products prepared when gas emission was incomplete. X-ray micro-tomography and mercury intrusion porosimetry showed that products formed during complete gas emission tended to have smaller pores. X-ray diffraction and nuclear magnetic resonance (27Al and 29Si) indicated that the aluminum substitution levels in tectosilicate differed under such conditions, although the minerals were identical. Thus, complete gas emission after mixing improved ultimate products.
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Affiliation(s)
- Kenji Shiota
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan.
| | - Takahiro Toda
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
| | - Kazuyuki Oshita
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan; Graduate School of Global Environmental Studies, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
| | - Takashi Fujimori
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan; Graduate School of Global Environmental Studies, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
| | - Hironori Kaji
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Ayaka Maeno
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Masaki Takaoka
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan; Graduate School of Global Environmental Studies, Kyoto University, Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
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Shiota K, Nakamura T, Oshita K, Fujimori T, Takaoka M. Quantitative cesium speciation and leaching properties in alkali-activated municipal solid waste incineration fly ash and pyrophyllite-based systems. Chemosphere 2018; 213:578-586. [PMID: 30268054 DOI: 10.1016/j.chemosphere.2018.09.097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/03/2018] [Accepted: 09/16/2018] [Indexed: 06/08/2023]
Abstract
There is an urgent need to dispose safely of the municipal solid waste incineration fly ash (MSWIFA) contaminated by cesium (Cs) released from the Fukushima Daiichi nuclear power plant accidents. This study investigated the relationship between quantitative Cs speciation and Cs immobilization in composite product from alkali-activated pyrophyllite and MSWIFA, with added stable cesium chloride and cesium carbonate. Cesium speciation was determined using X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS), while Cs immobilization was evaluated by a leaching method. Twenty-four composite products, with different Cs leaching properties, were prepared under various conditions. The XRD analysis of six composite products with different Cs leaching properties qualitatively identified a crystalline pollucite in the two products with the least Cs leaching. The quantitative speciation determined using XAFS revealed a strong negative correlation between the pollucite content in the 24 products and their Cs leaching ratio. Cesium species with a CsO bond were found in all products. These were at least two Cs species with different leaching properties. These results indicate that the change from a Cs species to pollucite in the product increased the Cs immobilization level in the system.
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Affiliation(s)
- Kenji Shiota
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan.
| | - Takafumi Nakamura
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
| | - Kazuyuki Oshita
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan; Graduate School of Global Environmental Studies, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
| | - Takashi Fujimori
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan; Graduate School of Global Environmental Studies, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
| | - Masaki Takaoka
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan; Graduate School of Global Environmental Studies, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8540, Japan
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