摘要
随着粗钢产量的逐年递增,我国钢渣累积存放量也不断上升,将钢渣用作辅助胶凝材料是提高钢渣综合利用率、降低水泥混凝土行业碳排放的有效措施。然而,钢渣存在的胶凝组分含量少且活性低、膨胀组分含量较高等问题限制了其在水泥和混凝土中的应用。目前,用于改善钢渣胶凝活性与体积稳定性的方法主要有机械粉磨、高温活化、碱活化、酸活化、有机物活化及碳化活化等。机械粉磨主要通过物理方式破坏钢渣晶体结构、减小颗粒粒径,但其能耗较高且仅对早期强度有利。高温活化主要包括高温养护和高温调质/重构:高温养护通过改变钢渣水化所处的外界环境促进水化,但较高温度会使钙矾石分解并引入孔洞;高温调质/重构工艺直接改变了钢渣的矿物组成,但存在能耗高和匀质性差的问题。碱活化可以促进离子溶出并消耗氢氧化钙,但存在碱骨料反应和泛碱等问题。酸活化也可以促进离子溶出,增大钢渣比表面积,但过量酸会消耗钢渣中活性组分。有机物活化中,醇胺可以通过络合作用促进离子溶出,但不同分子结构的醇胺作用机理仍不明确。碳化活化通过钙镁矿物与CO_(2)反应形成碳酸盐填充孔隙,但CO_(2)向试块内部的扩散阻力使内外碳化程度不均匀。通过钢渣的来源和组成,分析钢渣活性低和体积稳定性差的原因,归纳目前常见的改善钢渣胶凝活性和体积稳定性的方法,指出各方法目前面临的困境并作出展望,以期为钢渣性能的进一步优化和在水泥混凝土工业中的进一步应用提供参考。
With the yearly increase of crude steel production,the accumulated storage volume of steel slag in China is also rising,and the use of steel slag as supplementary cementitious material is an effective measure to improve the comprehensive utilization rate of steel slag and reduce the carbon emission of cement and concrete industry.However,steel slag has problems such as low content and low activity of the cementitious component and high content of swelling components,which limit its application in cement and concrete.At present,many methods are used to improve the cementitious activity and volume stability of steel slag,including mechanical grinding activation,high temperature activation,acid activation,alkali activation,organic activation and carbonization activation.Mechanical grinding activation mainly through the physical way to break the steel slag crystal structure and reduce the particle size,but it has high energy consumption and only for the early strength benefit.High temperature activation mainly includes high temperature curing and high temperature reconstruction.High temperature curing promotes hydration by changing the external environment in which the steel slag is hydrated,but the higher temperature will cause the decomposition of ettringite and introduce pores.High temperature reconstruction process directly changes the mineral composition of the steel slag,but there are problems such as high energy consumption and poor homogeneity.Alkali activation can promote ion dissolution and consume calcium hydroxide,but there are problems such as alkali aggregate reaction and efforescence.Acid activation can promote ion dissolution and increase the specific surface area of steel slag,but it will react with the active components in steel slag.In organic activation,alkanolamines can promote ion dissolution through complexation,but the mechanism of action of alkanolamines with different molecular structures is still unclear.Carbonation fills the pores through the reaction of calcium and magnesium minerals with
作者
王剑锋
常磊
王艳
刘辉
岳德钰
崔素萍
兰明章
WANG Jianfeng;CHANG Lei;WANG Yan;LIU Hui;YUE Deyu;CUI Suping;LAN Mingzhang(Key Laboratory of Advanced Functional Materials,Ministry of Education,Facaulty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China)
出处
《材料导报》
CSCD
北大核心
2023年第11期115-123,共9页
Materials Reports
基金
北京市自然科学基金-市教委联合资助项目(KZ202010005013)
国家自然科学基金(51504013)。
关键词
钢渣
组成
胶凝活性
体积稳定性
有机活化
steel slag
compositions
cementitious reactivity
volume stability
organic activation
