Optimised steel slag carbonation for enhanced CO₂ sequestration: A comprehensive study using response surface...

Area of Science:

• Environmental Science
• Chemical Engineering
• Materials Science

Background:

• Mineral carbonation offers a promising route for carbon dioxide (CO2) sequestration.
• Steel slag, a byproduct of steel manufacturing, presents a viable material for CO2 mineral carbonation.
• Optimizing reaction conditions is crucial for maximizing CO2 capture efficiency in steel slag.

Purpose of the Study:

• To optimize the conditions for CO2 sequestration in steel slag using mineral carbonation.
• To investigate the impact of key variables (time, temperature, pressure, liquid/solid ratio) on CO2 capture efficiency.
• To determine the ideal reaction parameters for maximizing CO2 sequestration in steel slag.

Main Methods:

• Response Surface Methodology (RSM) was employed to systematically optimize reaction parameters.
• Variables studied included reaction time, temperature, pressure, and liquid/solid ratio.
• Experimental validation was performed to confirm the predicted optimal conditions.

Main Results:

• CO2 sequestration efficiency was significantly influenced by the interplay between reaction time and temperature.
• Increasing temperature (20°C to 90°C) and time (1 to 4 days) resulted in a 48% increase in CO2 sequestration in ladle slag.
• Enhanced CO2 capture was observed with increased pressure and liquid/solid ratio, up to a certain threshold.

Conclusions:

• Optimal conditions for CO2 sequestration in steel slag were predicted using RSM: 60.83°C, 1 day, 15.63 bar, and a 90/30 liquid/solid ratio.
• Experimental validation confirmed the predicted conditions, yielding 118.03 kg CO2 per tonne of steel slag with a 2.04% relative error.
• This study demonstrates the potential of steel slag for efficient CO2 sequestration through optimized mineral carbonation processes.