Japan Geoscience Union Meeting 2014

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[U-05_30AM2] Interrelation between Life, Water, Mineral, and Atmosphere

Wed. Apr 30, 2014 11:00 AM - 12:45 PM 419 (4F)

Convener:*Tsubasa Otake(Division of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University), Yohey Suzuki(Graduate School of Science, The University of Tokyo), Fumito Shiraishi(Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University), Ken Takai(Extremobiosphere Research Center, Japan Agency for Marine-Earth Science & Technology), Yuichiro Ueno(Department of Earth and Planetary Sciences, Tokyo Institute of Technology), Takeshi Naganuma(Graduate School of Biosphere Science), Takeshi Kakegawa(Graduate School of Science, Tohoku University), Tadashi Yokoyama(Department of Earth and Space Science, Graduate School of Science, Osaka University), Kentaro Nakamura(Precambrian Ecosystem Laboratory (PEL), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)), Chair:Tadashi Yokoyama(Department of Earth and Space Science, Graduate School of Science, Osaka University), Kentaro Nakamura(Precambrian Ecosystem Laboratory (PEL), Japan Agency for Marine-Earth Science and Technology (JAMSTEC))

12:30 PM - 12:45 PM

[U05-11] Re-evaluation of mineral particles in geothermal fluid: Focus on polysilicic acid and adsorbed particles

*Kotaro YONEZU1, Chisato MASUDA1, Sachi MASUNAGA2, Mayumi ETOU2, Koichiro WATANABE1, Takushi YOKOYAMA2 (1.Dept. of Earth Resources Engineering, Kyushu Univ., 2.Dept. of Chemistry, Faculty of Sciences, Kyushu Univ.)

Keywords:polysilicic acid, geothermal fluid, binary power generation, polymerization of silicic acid, mineral particles

In geothermal system, the solubility of monosilicic acid concentration in geothermal fluid is controlled by physicochemical conditions. Once the supersaturated condition with respect to amorphous silica attained, the polymerization of silicic acid begins followed by the formation of the particles of polysilicic acid. In addition, the particles adsorbed on the solid surface can be a trigger for the further siliceous deposit. Therefore, in order to investigate the formation mechanism of siliceous deposit, the polysilicic acid particles formed by polymerization of silicic acid and the particles adsorbed on the solid surface in geothermal fluid are focused in terms of those size and chemical composition. In this study, the polymerization mechanism of silicic acid is discussed based on the size variation of polysilicic acid in geothermal fluid as a function of time measured by dynamic light scattering (DLS) in addition to TEM observation of fractionated polysilicic acid. The filtered particles with different pore size and the adsorbed particles on the copper pipe are analyzed by SEM-EDX to characterize the particle size and chemical composition of the particles. We expect that these results can be basic information for the prevention technology of siliceous deposit formation on the surface of heat exchanger during geothermal binary power generation.