(411f) Carbon Mineral Sequestration in New York State Using Wollastonite

Park, A. H. A., Columbia University
Zhao, H., Columbia University

Carbon mineralization is one of the safest methods of sequestering anthropogenic carbon dioxide. It is based on the reaction of carbon dioxide with the metal ions present in silicate minerals to form geologically and thermodynamically stable mineral carbonates. Thus, this sequestration method allows virtually permanent carbon dioxide containment that does not require monitoring. Furthermore, the accounting and the certification of the stored carbon would be straightforward for this technology.

For large scale carbon mineral sequestration processes, magnesium silicate is the most suitable minerals due to its abundance in nature which far exceeds the coal reserve. Thus, the research on CO2 mineralization has been focused on magnesium silicate minerals such as olivine (Mg2SiO4) and serpentine (Mg3Si2O5(OH)4). Calcium silicates including wollastonite (CaSiO3) is relatively rare, and thus, it has not been actively investigated for carbon sequestration. The largest deposits of wollastonite in the United States, however, exist in New York State. It is estimated that there is 7 ? 14 Mt of wollastonite, which can store 2-5 million tons of carbon dioxide. Therefore, CO2 mineralization using wollastonite could be one of the best options for New York State, which has relatively few options for carbon storage.

Our study focuses on the development of carbon mineralization process using wollastonite of New York State. Both technical and economical feasibilities are evaluated based on the two step dissolution-carbonation process developed from the pH swing technology. The effects of pH and temperature on the treatment of wollastonite are investigated, while gluconic acid is employed as the chemical enhancer for the mineral dissolution. For the carbonation step, carbonic anhydrase is used to improve the carbonation rate at near neutral pH conditions. The chemical and morphological properties of precipitated calcium carbonates are evaluated for its industrial applications as value-added products.