Preparation of ultra-high strength carbonated compacts via accelerated carbonation of magnesium slag

Abstract

This study investigates the preparation of ultra-high strength carbonated compacts from magnesium slag via accelerated carbonation under synergistic effects of degree of compaction (DC) and CO2 partial pressure. Magnesium slag exhibited high potential for carbonation reactivity based on isothermal calorimetry, thermogravimetric analysis, and pH value measurements. The compressive strength of carbonated magnesium slag compacts depended strongly on DC and CO2 partial pressure. At optimal conditions of DC 62 % and CO2 partial pressure 0.2 MPa, the compressive strength reached 252.3 MPa. The underlying mechanisms were revealed through analysis of CO2 uptake, porosity, CaCO3 content, and calcite particle size. Lower CO2 partial pressure benefited carbonation of compacts with higher DC by enabling uniform carbonation product distribution. This research offers novel perspectives on the creation of exceptionally robust carbonated products utilizing solid waste via accelerated carbonation.

Keywords

• Carbonatable binders
• Magnesium slag
• Accelerated carbonation
• CO2 Partial pressure
• Degree of compaction