Abstract: To achieve the synergistic governance of carbon reduction and the reduction of solid waste from coal combustion, an expansion test was conducted to prepare artificial aggregates using CO₂ mineralized circulating fluidized bed （CFB） ash and slag. This study investigated the effects of various pretreatment methods on the composition and structure of CFB slag, as well as the influence of different pre-curing techniques on the compressive strength of formed material blanks. The microscopic morphology and pore structure changes of the aggregates before and after mineralization curing were analyzed by SEM and BET. The results show that coal ash has a higher specific surface area and richer pore structure after ball milling. Compared with air curing, sealed curing can significantly improve the early strength of aggregate and shorten the pre-curing time. Under the conditions of flue gas CO₂ temperature of 60 ℃, flue gas concentration of 15% and normal pressure, the average strength of a single aggregate after mineralization curing for 8 h reached 4.06 MPa, the free calcium oxide content in the aggregate decreased from 11.94% to 6.48%, and the carbon fixation rate was 5.22%. Through SEM and BET analysis, it can be seen that after pre-curing, the molded material embryo forms C−S−H gel and Ca（OH）₂ hydration products, which have high early strength; after mineralization curing, the hydration products are transformed into calcite-shaped calcium carbonate products, which further fill the pores less than 100 nm in the aggregate, densify the aggregate structure and improve the compressive strength. In addition, the problems encountered in the expansion test were analyzed and improvement suggestions were put forward, in order to provide ideas for the engineering application of solid waste mineralization CO₂ technology.