RCRE: Appropriate Technology for CO2 Reduction: Utilization of Non-captured CO2 & Development of New Supplementary Cementitious Materials (只有英文版本)

Abstract

Geological storage for CO₂ is very limited considering potential geological region and cost for CO₂ processing. Compared to the geological storage, mineral carbonation has benefits such as low cost for CO₂ processing and solidification. Although cement does contribute to the CO₂ emission during its manufacturing process, it also has potential to re-absorb CO₂ by carbonation. In this talk, ex-situ calcite precipitation will be discussed based on lab-scale case studies using cementitious materials or industrial by-products. For instance, under 10% of CO₂ concentration, 30 min of in-situ CO₂ mixing does allow the calcite precipitation. The amount of produced calcite mineral in a very early age was compared among GEMS, Rietveld-based XRD method, and TGA method. Specifically, TGA data revealed that the decomposition temperature of the precipitated calcite lower than that of typical calcite crystal. It indicates the crystal size of the produced calcite minerals is very small. Furthermore, it was confirmed that the early CO₂ mixing induced the calcite precipitation which was not a result of conventional carbonation behaviour. At the very early age of hydration, calcite was precipitated by the direct reaction between CO₂ and dissolved Ca ions in mixing water. Therefore, it can be proposed that the early age of calcite precipitation may not impact the pH value which has been treated as critical cause of any damage from the carbonation reaction. Further verification such as pH variation or corrosion test is being conducted to validate this observation. If it is confirmed, the very early age in-situ CO₂ mixing can be utilized for using cement-based composites as a carbon sink that can help to permanently consume emitted CO₂ gas from cement and other industries.

Biography

Dr Juhyuk Moon is an Associate Professor in the Department of Civil and Environmental Engineering at Seoul National University. He has experience on research and teaching at Stony Brook University, US and National University of Singapore as well. He is currently studying mineral carbonation technology as an Appropriate Technology for CO₂ reduction. He is taking a Convenor role of ISO TC 265 AHG1 Carbon Capture, Transportation, and Geological Storage which aims to establish some guideline to quantitatively calculate the amount of CO₂ reduction through various mineral carbonation based CCUS technologies.