著者
張 其武 齋藤 文良
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.114, no.4, pp.253-257, 1998-04-25
被引用文献数
11 30

Leaching of fluorescent powder containing rare earths using 1N HCl solution at room temperature was conducted to extract the rare earths, followed by dry grinding of the powder using a planetary ball mill. The dry mechanochemical treatment of the powder causes the structural change of the crystals in the powder into a disordered system. This mechanochemical treatment leads to easy extraction of the rare earths. Only 3 minutes of grinding enables us to extract Y and Eu at above 70-80 % yield. More than 80 % of the other rare earths can be extracted from the powder ground for 2-hours. The mechanochemical treatment to the fluorescent powder before leaching would be an effective operation to be able to extract the rare earths at high yield in room temperature leaching even by low concentration HCl solution.
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

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/cm<sup>3</sup>. 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.