碳酸化预处理钢渣体积安定性和水化活性的影响

Effects of carbonation on volume stability and hydration activity of steel slag

钢渣是粗钢冶炼过程中产生的一种工业废渣,目前我国钢渣的综合利用率较低,大量的钢渣堆积不仅是资源的浪费也对环境造成了污染。钢渣的体积安定性差、易磨性差、水化活性低是限制钢渣在在混凝土中应用的主要因素。通过二氧化碳气体对钢渣进行预处理,分析了碳酸化预处理对钢渣固碳量、碳酸化产物、体积安定性和水化活性的影响。结果表明,钢渣中的f-CaO和f-MgO可迅速与CO2反应形成碳酸盐从而改善钢渣的体积安定性,碳酸化预处理6 min即可使钢渣达到安全使用的范围。C3S,C2S等也可与CO2反应从而降低钢渣的水化活性,但碳酸化预处理对钢渣的3 d抗压强度影响较大,对28 d抗压强度影响较小。

Steel slag is a kind of waste residue produced during the smelting process of crude steel.The comprehensive utilization of steel slag in China is low and the accumulation of large amounts of slag is not only a waste of resources but also causes pollution to the environment.The poor volume stability,grindability and hydration activity of steel slag are the main factors affecting the application of steel slag in the field of building materials.In this paper,steel slag was pretreated by carbon dioxide,and the effects of carbonation on carbon uptake,carbonation products,volume stability and hydration activity of steel slag were analyzed.The results indicated that f-CaO and f-MgO in steel slag can rapidly react with CO2 to form carbonate to improve the volume stability of steel slag.Carbonation pretreatment for only 6 minutes can reduce autoclaved expansion of steel slag to 0.5%.C3S and C2S can also react with CO2 to form calcium carbonate and reduce the hydration activity of steel slag,but carbonation pretreatment has a greater influence on the 3d compressive strength of steel slag and less influence on 28d compressive strength.