In-situ Test on CO_2 Fixation by Serpentinite Rock Mass in Japan

摘要

Serpentinite rock mass with highly alkaline groundwater has a potential of CO_2 mineral carbonation. The aim of this study is to develop the efficient CO_2 fixation system by serpentinite rock mass in Japan with in-situ CO_2 injection tests. It is possible that the combination process of dissolution of the serpentine and following formation of the amorphous silicate after CO_2 injection into the serpentinite-groundwater system increases the Mg component in the groundwater. Mg carbonates possibly precipitate by the reaction between injected CO_2 and excess Mg. As indicated by tomography, the electrical resistivity of the rock mass was changed, then it was clarified that CO_2 affects groundwater within 25 m for several hours. Phase diagrams of the Mg-Si-CO_2 system were obtained using PHREEQC, and enabled to estimate mineral dissolution and precipitation in serpentinite rock with CO_2.