China Nonferrous Metallurgy

Metallurgical and cement industries were the main industries of CO₂ emission in the world, and has been faced a huge challenge of “carbon emission reduction”. Steel slag, a solid waste produced by metallurgical industry, has high carbonation reactivity into a CO₂ rich environment. In this paper, the CO₂ capturing capacity of steel slag under room temperature and atmospheric pressure was explored. Carbonated steel slag admixture for cement industry was prepared. And its influences on the fluidity, mechanical properties and microstructures of cement-based materials were investigated. The results showed that the carbonation weight gain of steel slag could reach 9.11%, indicating that about 90kg CO₂ could be captured by per ton of steel slag. Due to the porous microstructures of carbonated steel slag, the water absorption rate was increased, which had a certain impact on the fluidity of cement mortar. The mechanical strength of cement mortars mixed with carbonated steel slag was better than that of mixed with non-carbonated steel slag, and the higher the carbonation weight gain, the higher the 28d compressive strength of cement mortar.