Using TOF-SIMS isotope mapping for studying dissolution and precipitation processes at mineral grains in an experimental CO (sub 2) -sequestration setup
Using TOF-SIMS isotope mapping for studying dissolution and precipitation processes at mineral grains in an experimental CO (sub 2) -sequestration setup (in Goldschmidt abstracts 2013, Anonymous)
Mineralogical Magazine (2013) 77 (5): 2065
CCS (Carbon dioxide capture and sequestration) is a technique investigated for its possible employment in the reduction of the amount of anthropogenic CO (sub 2) gas emitted into the atmosphere. Deep saline aquifers are one option for storing CO (sub 2) gas streams produced e.g. by the combustion of fossil fuels at power plants. These gas streams contain different impurities depending on their origin, among them O (sub 2) , NO (sub x) , SO (sub x) in addition to the CO (sub 2) . We have used ToF-SIMS to determine the influence of these impurities on dissolution and precipitation processes at the minerals. Experiments under in situ pressure and temperature conditions of possible geological storage sites were performed at the German Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR) in flexible Dickson-type gold-titanium cells and small gold capsules. Minerals common in the deep saline aquifers (e.g. siderite, calcite) were placed in small reaction cells of thin gold foil in a reactor vessel and exposed to isotopically enriched water (H (sub 2) (super 18) O) or carbon dioxide ( (super 13) CO (sub 2) ) during the experiments. To facilitate the determination of the amount of dissolved ions incorporated into newly formed precipitates within the reaction chambers, a database of positive and negative ToF-SIMS spectra for a variety of rock-forming minerals were set up to identify minerals and mineral alterations. In addition, preparation techniques were developed for high-resolution measurements of the incorporation of isotope-labeled elements/ions (e.g. (super 18) O) into mineral precipitates. The results show that ToF-SIMS can simultaneously image the elemental, isotopic, and molecular compositions of these minerals with high spatial resolution. Also, elemental and isotopical distributions as a function of depth can be monitored.