Econ. Environ. Geol. 2009; 42(5): 403-412

Published online October 31, 2009

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

Study for the Geochemical Reaction of Feldspar with Supercritical CO2 in the Brine Aquifer for CO2 Sequestration

Wonwoo Choi, Hyunmin Kang, Jaejung Kim, Jiyoung Lee and Minhee Lee*

Department of Environmental Geosciences, Pukyong National University, 599-1 Daeyon 3 Dong, Namgu, Busan, 608-737, Republic of Korea

Correspondence to :

Minhee Lee

heelee@pknu.ac.kr

Received: September 3, 2009; Accepted: October 11, 2009

Abstract

The objective of this study is to investigate the geochemical change of feldspar minerals by supercritical CO2, which exists at CO2 sequestration sites. High pressurized cell system (100 bar and 50oC) was designed to create supercritical CO2 in the cell and the surface change and the dissolution of plagioclase and orthoclase were observed when the mineral surface reacted with supercritical CO2 and water (or without water) for 30 days. The polished slab surface of feldspar was contacted with supercritical CO2 and an artificial brine water (pH 8) in the experiments. The experiments for the reaction of feldspar with only supercritical CO2 (without brine water) were also conducted. Results from the first experiment showed that the average roughness value of the plagioclase surface was 0.118 nm before the reaction, but it considerably increased to 2.493 nm after 30 days. For the orthoclase, the average roughness increased from 0.246 nm to 1.916 nm, suggesting that the dissolution of feldspar occurs in active when the feldspars contact with supercritical CO2 and brine water at CO2 sequestration site. The dissolution of Ca2+ and Na+ from the plagioclase occurred and a certain part of them precipitated inside of the high pressurized cell as the form of amorphous silicate mineral. For the orthoclase, Al3+, K+, and Si4+ were dissolved in order and the kaolinite was precipitated. In the experiments without water, the change of the average roughness value and the dissolution of feldspar scarcely occurred, suggesting that the geochemical reaction of feldspars contacted with supercritical CO2 at the environment without the brine water is not active.

Keywords CO2 sequestration, supercritical CO2, feldspar dissolution, geochemical reaction, brine aquifer

Article

Econ. Environ. Geol. 2009; 42(5): 403-412

Published online October 31, 2009

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

Study for the Geochemical Reaction of Feldspar with Supercritical CO2 in the Brine Aquifer for CO2 Sequestration

Wonwoo Choi, Hyunmin Kang, Jaejung Kim, Jiyoung Lee and Minhee Lee*

Department of Environmental Geosciences, Pukyong National University, 599-1 Daeyon 3 Dong, Namgu, Busan, 608-737, Republic of Korea

Correspondence to:

Minhee Lee

heelee@pknu.ac.kr

Received: September 3, 2009; Accepted: October 11, 2009

Abstract

The objective of this study is to investigate the geochemical change of feldspar minerals by supercritical CO2, which exists at CO2 sequestration sites. High pressurized cell system (100 bar and 50oC) was designed to create supercritical CO2 in the cell and the surface change and the dissolution of plagioclase and orthoclase were observed when the mineral surface reacted with supercritical CO2 and water (or without water) for 30 days. The polished slab surface of feldspar was contacted with supercritical CO2 and an artificial brine water (pH 8) in the experiments. The experiments for the reaction of feldspar with only supercritical CO2 (without brine water) were also conducted. Results from the first experiment showed that the average roughness value of the plagioclase surface was 0.118 nm before the reaction, but it considerably increased to 2.493 nm after 30 days. For the orthoclase, the average roughness increased from 0.246 nm to 1.916 nm, suggesting that the dissolution of feldspar occurs in active when the feldspars contact with supercritical CO2 and brine water at CO2 sequestration site. The dissolution of Ca2+ and Na+ from the plagioclase occurred and a certain part of them precipitated inside of the high pressurized cell as the form of amorphous silicate mineral. For the orthoclase, Al3+, K+, and Si4+ were dissolved in order and the kaolinite was precipitated. In the experiments without water, the change of the average roughness value and the dissolution of feldspar scarcely occurred, suggesting that the geochemical reaction of feldspars contacted with supercritical CO2 at the environment without the brine water is not active.

Keywords CO2 sequestration, supercritical CO2, feldspar dissolution, geochemical reaction, brine aquifer

    KSEEG
    Apr 30, 2024 Vol.57 No.2, pp. 107~280

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