Experiment on mircon bubbles and ultrasonic-assisted wet carbonation for recycled micro-powder and artificial aggregate

Abstract:

Recycled micro-powder has excellent carbon sequestration potential, and the wet carbonation method enhances its carbon sequestration performance. In this study, micron bubbles and ultrasonic-assisted methods were used to improve the carbon sequestration efficiency of wet carbonation. Then the recycled micro-powder slurry after carbonation was compressed into artificial aggregate, and a secondary carbonation was further conducted to improve the mechanical strength of artificial aggregate. The CO₂ volumetric method of aluminum film bag was proposed to evaluate the carbon sequestration amount and carbonation degree of recycled micro-powder. Finally, the carbon footprints of this carbonated recycled micro-powder and artificial aggregate are calculated. The results indicate that the wet carbonation method proposed in this study can effectively improve the carbonation efficiency of recycled micro-powder. The use of aluminum film bag for CO₂ volumetric method of the carbon fixation in recycled micro-powder is straghtforward and practical. The carbon sequestration amount of recycled micro-powder in aluminum film bag with 100% CO₂ concentration for 0.5 h is comparable to that of the wet carbonation method proposed in this study for 5 minutes. The compressive strength of the artificial aggregate made of non-carbonated recycled micro-powder is 42.7 MPa after carbonation curing. However, when recycled micro-powder treated with wet carbonation is remolded into artificial aggregates, the post-carbonation strength is relatively lower compared to the control group, mainly due to the reduction of carbonation reactants. Carbon footprint calculation shows that carbonized recycled micro-powder artificial aggregates can achieve a significant reduction in carbon emissions.