钢渣中游离氧化钙和游离氧化镁水化性能及钢渣胶凝材料的安定性

A large amount of steel slag is produced in the iron and steel industry every year, but it has not been able to achieve high volume application in cement and concrete industry for its low cementitious activity and the poor stability caused by the volume expansion of free calcium oxide and free magnesium oxide after hydration. The main contents of the project are as follows: study the generation process and hydration properties of free calcium oxide and free magnesium oxide in steel slag, clarify the hydration rules of free calcium oxide and free magnesium oxide in steel slag and its influencing factors, and reveal the hydration properties of RO phase (bivalent metal oxide solid solution) in steel slag and its effect on the stability of steel slag cementitious materials; put forward the evaluation methods and standards of stability of steel slag and establish the corresponding theoretical or empirical mathematical model; propose the measures to accelerate and strengthen the hydration process and degree of free magnesium oxide and free calcium oxide in steel slag, improve the poor stability caused by the volume expansion of free calcium oxide and free magnesium oxide after hydration and increase the content of steel slag powder in cementitious materials. The expected results can provide theoretical and experimental basis for high volume application of steel slag powder and steel slag-blast furnace slag composite powder, and improve the utilization level of solid waste residue in steel industry. This project conforms to the sustainable development strategy and the demand of modern concrete development. It also conforms to the mainstream of circular economy and has obvious economic, social and environmental benefits.

钢铁工业中钢渣年产生量大，但因其活性低、尤其是其中的游离氧化钙和游离氧化镁水化后体积膨胀存在安定性问题一直未能在水泥和混凝土中实现大掺量利用。本项目主要研究钢渣中游离氧化钙和游离氧化镁的生成过程和水化性能，明晰钢渣中游离氧化镁和游离氧化钙的水化规律及其影响因素，揭示钢渣中二价金属氧化物固溶体RO相的水化性能及其对钢渣和钢渣水泥胶凝材料安定性的影响。依据层次分析法提出评价钢渣安定性的方法和标准，建立相应的理论或经验数学模型。提出加速和强化钢渣中游离氧化镁和游离氧化钙水化过程和程度的措施，改善钢渣中因游离氧化钙和游离氧化镁水化膨胀产生的安定性问题，提高钢渣粉配制胶凝材料的掺量。预期成果可为钢渣粉、钢渣和矿渣复合粉大掺量应用提供理论和实验依据，采用预期成果可提高钢铁工业固体废渣资源化的利用水平。项目符合可持续发展战略和现代混凝土发展的需求，顺应循环经济发展主流，具有明显的经济、社会和环境效益。

我国钢铁工业中钢渣年产生量1.3亿吨以上，但因其活性低、尤其是其中的游离氧化钙和游离氧化镁水化后体积膨胀存在安定性问题一直未能实现大掺量利用。项目主要研究钢渣中游离氧化钙和游离氧化镁的组成和水化性能；钢渣中RO相的组成和水化性能及其对钢渣水泥胶凝材料安定性的影响；碳化对钢渣中游离氧化钙和RO相的水化过程和性能的影响；钢渣安定性评价方法以及减弱和消除掺钢渣粉胶凝材料膨胀性的措施。重要结果分为三部分：一是揭示和明晰影响钢渣中f-CaO的组成和水化过程规律，典型钢渣中的f-CaO含有钙铁锰矿物相。在实验室分别制备含有CaO-FeO-MnO、Ca2Fe2O5和CaO-FeOx的三组分和二组分的f-CaO，得出不同组成的f-CaO在室温、沸煮和压蒸条件水化活性的规律。二是在实验室分别制备不同组成的四组分MgO-FeO-MnO-CaO、三组分MgO-FeO-MnO和二组分MgO-FeO的RO相，得出不同组成的RO相的水化活性规律及其对钢渣胶凝材料膨胀性的影响规律。对制备的不同组成的f-CaO和RO相进行碳化处理以改善其体积安定性。分别得出f-CaO和RO相与掺钢渣粉胶凝材料膨胀性之间关系的数学模型。三是初步建立了钢渣水泥胶凝材料安定性评价方法的数学模型，科学地评价钢渣的体积安定性。当新余钢铁公司的钢渣掺量低于30%，湛江钢渣掺量低于20%，首钢钢渣低于25%时，钢渣水泥胶凝材料的压蒸膨胀率实际测量值与采用建立的数学模型的计算值吻合。提出减弱和消除钢渣中游离氧化钙和RO相膨胀产生安定性的具体措施，具体为：通过碳化钢渣减弱其膨胀性、在钢渣水泥复合胶凝材料中添加纤维增强其性能和在钢渣水泥复合胶凝材料中添加纳米氧化铝增强其性能，例如添加1%纳米γ-Al2O3的钢渣水泥胶砂试样3d抗压强度可提升26.26%，钢渣水泥净浆试样的沸煮和压蒸膨胀率分别降低50.24%和50.19%。研究成果可为钢渣粉、钢渣和矿渣复合粉大掺量应用提供理论和实验依据，采用研究成果可提高钢铁工业固体废渣资源化的利用水平。项目符合可持续发展战略和现代混凝土发展的需求，顺应循环经济发展主流，具有明显的经济效益、社会和环境效益。

内容获取失败，请点击重试