著者

萩野 隆生 平島 剛

出版者

一般社団法人 環境資源工学会

雑誌

環境資源工学 (ISSN:13486012)

巻号頁・発行日

vol.52, no.4, pp.172-182, 2005 (Released:2005-12-08)

参考文献数

7

被引用文献数

13 12

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A novel process for effectively recovering phosphorus from waste has been developed. By this process, magnesium ammonium phosphate (hereinafter referred to as MAP) is recovered from anaerobic digestive sludge in sewage. The MAP recovery process involves recovering inorganic fine particles, which include the MAP particles, from digestive sludge through a successive line of separating devices such as, a vibrating screen, a hydro-cyclone, and a revolving-cylindrical type thin flow separator or multi-gravity separator. Continuous tests for MAP recovery carried out to study the performance of this process indicate that it was possible to recover about 90% of MAP.

著者

林 良和 郭 柄霖 平島 剛 伊藤 竜也 中村 壮志 笹木 圭子

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.135, no.7, pp.63-70, 2019-07-31 (Released:2019-07-31)

参考文献数

23

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Removal of borate in mine drainages by co-precipitation with hydroxyapatite (HAp) was developed from a laboratory scale to a pilot scale. Weakly acidic initial pH facilitated to enhance dissolution of Ca(OH)2 and decrease the dissolved carbonate concentration, leading to efficient immobilization of borate and arsenate. The NH4H2PO4 lowered best the equilibrium B concentration among different phosphate sources, avoiding the lattice strain of HAp. The added molar ratio of P/Ca significantly influenced the decreasing behavior of the B concentration, showing the optimal value of 0.3. In case of P/Ca larger than 0.30, the excess concentration of PO43- was probably adsorbed on Ca(OH)2 particles to prevent the dissolution, resulting in inhibiting the formation of HAp. In case of P/Ca smaller than 0.30, the production of HAp was limited, leading to less immobilized borate. All the optimized conditions as above were applied to the pilot scale with a 250 L reactor, where borate concentration was effectively reduced in also both batch and continuous tests.

著者

井上 聡大 羅 武輝 森山 紗好 平島 剛 島田 英樹 笹木 圭子

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.133, no.10, pp.235-240, 2017-10-01 (Released:2017-10-14)

参考文献数

28

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Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident produced much amount of radioactively contaminated water at the Great East Japan Earthquake. 137Cs and 90Sr have been focused to remove from the contaminated water using zeolite types of adsorbents. Other radionuclides have been treated and removed separately by Advanced Liquid Processing System (ALPS), where resin is used to immobilize anions. However, these kinds of spent-adsorbents are not suitable for long-terms burying because of its instability, and the representative anionic radionuclides (129I, 36Cl, 99mTc and 79Se) have quite long half-life (105-107 years). Montmorillonite (Mt) is an useful adsorbent because of its high chemical stability and large cationic exchange capacity. In the present work, surfactant modified Mt (OMt) has been developed using hexadecylpyridium chloride for adsorption of ClO4-, which is a surrogate of 99mTcO4-. For stabilization of spent-OMt, cement solidification was examined with varying the ratio of spent-OMt content. To evaluate its chemical and physical stability, soaking and compressive strength tests were conducted. As a result, it was revealed by FTIR and 29Si-NMR that with increase in OMt contents, the linkage of calcium silicate hydrate was more developed.

著者

平島 剛 保坂 文教 本多 覚 恒川 昌美 伊藤 正澄 佐川 孝広

出版者

The Mining and Materials Processing Institute of Japan

雑誌

資源と素材 : 資源・素材学会誌 : journal of the Mining and Materials Processing Institute of Japan (ISSN:09161740)

巻号頁・発行日

vol.119, no.9, pp.553-558, 2003-09-25

被引用文献数

2 2

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Fine waste concrete smaller than 5mm obtained from a recycling plant of waste concrete was used as feed and ground by a wet attrition mill. Recovery of the fine aggregate and cement hydrate powder from the ground fine waste concrete was investigated using a laboratory / pilot scale Mozley multi-gravity separator (MGS). The water absorption of the fine aggregate obtained as the high specific gravity product was less than 3.5 % and the dry density was larger than 2.4 g/cm³. The powder obtained as low specific gravity product contained about 29 % of fine aggregate. The reference for normal clinker and the mixture prepared by mixing the reference materials with 38 wt% of the powder were heated at 1,500 °C, with the hydraulic modulus adjusted to 2.18, the silica modulus to 2.8, and the iron modulus to 1.64. The phases of the clinker were identified and quantitatively determined by a microscopic point-count procedure and by the Rietveld analysis using XRD data. There was good agreement in the clinker minerals of the reference and the mixture clinkers. These results show that the fine aggregate and cement hydrate powder recovered from fine waste concrete by MGS can be recycled in cement and concrete production.