Fundamental Studies on CO2 Sequestration of Concrete Slurry Water Using Supercritical CO2

Abstract

To prevent drastic climate change due to global warming, it is necessary to transition to a carbon-neutral society by reducing greenhouse gas emissions in all industrial sectors. This study aims to prepare measures to reduce the greenhouse gas in the cement industry, which is a large source of greenhouse gas emissions. The research uses supercritical CO2 carbonation to develop a carbon utilization fixation technology that uses concrete slurry water generated via concrete production as a new CO2 fixation source. Experiments were conducted using this concrete slurry water and supernatant water under different conditions of temperature (40 and 80 °C), pressure (100 and 150 bar), and reaction time (10 and 30 min). The results showed that reaction for 10 min was sufficient for complete carbonation at a sludge solids content of 5%. However, reaction products of supernatant water could not be identified due to the presence of Ca(HCO3)2 as an aqueous solution, warranting further research.

Supercritical CO2 Curing of Resource-Recycling Secondary Cement Products Containing Concrete Sludge Waste as Main Materials

“…During the determined reaction time, specimens were undergoing Lean Carbonation. Most studies on mineral carbonation based on supercritical CO 2 were conducted in the ranges of 30-50 • C and 80-100 bar [32]. Based on these conditions, in this study, the temperature and pressure conditions were set to 35 • C and 80 bar and 40 • C and 100 bar, close to the supercritical CO 2 critical point (31.1 • C and 73.8 bar); the carbonation depth was measured by varying the curing time from 1 to 5, 10, 30, and 60 min.…”

Effect of the Concrete Slurry Waste Ratio on Supercritical CO2 Sequestration

“…Therefore, in a previous study [ 26 ], mineral carbonation by supercritical CO 2 was performed for CSW, in which the CSW ratio was adjusted to 5% at a set temperature (40 and 80 °C) and pressure (100 and 150 bars) conditions based on previous studies. It was confirmed that complete carbonation occurred within only 10 min at 40 °C and 100 bar.…”