高活性安定性钢渣在线调控及其动态化学重构机理研究

The on-line reconstruction of molten steel slag by using its sensible heat is proposed as one of the most promising approaches to solve the variation in chemical composition, low activity and poor stability of slag. However, the mixing and regulation of molten slag and the conditioning components are the key scientific problems for the on-line reconstruction of steel slag. In the present study, converter steel slag is proposed to be the research object for simulating on-line reconstruction process of the molten steel slag. According to the phase diagram of Portland cement clinker, mineral structure and target composition, the design of conditioning components will be optimized, and the key parameter such as reconstruction temperature will be determined. A metallogenic dynamics and thermodynamics model will be set up by analyzing the relationship of "viscosity - temperature - chemical composition" of steel slag. The influence of mixing methods (internal and external mixing), atmosphere conditions (oxidation, reduction and inertia), and process measures (such as temperature control, drum gas position) on rheological properties, temperature field distribution, diffusion characteristics of on-line regulation of steel slag will be investigated, and the relation model of diffusion dynamics, non-isothermal crystallization kinetics and reaction thermodynamics under the various factors will be established. Moreover, the dynamic chemical reconstruction mechanism of slag will be ascertained. Based on the promotion of activity and stability of the slag, a new technology of on-line regulation of steel slag is provided. The research results will make full use of the molten steel slag sensible heat and provide a new way of efficient utilization of steel slag, which provides a theoretical basis for efficient application of building materials, and metallurgical slag.

利用熔融钢渣显热进行钢渣“在线重构”的技术思路，是解决钢渣化学组成波动大，胶凝活性低和安定性差等问题的有效途径。但是，调质组分和熔融钢渣的均混和调控是实现钢渣在线重构的关键科学问题。本课题拟以转炉钢渣为研究对象，模拟熔融钢渣在线重构过程，根据硅酸盐水泥熟料相图、矿物结构及目标成分，优化调质组分设计，确定温度制度等重构关键参数，分析重构钢渣“化学成分-温度-粘度”的关系，建立成矿动力学和热力学模型；研究均混手段（内部和外部均混）、气氛条件（氧化、还原和惰性）、工艺措施（温度调节、鼓气位置）等对在线调控钢渣的流变特性、温度场分布、扩散特征的影响规律，建立各因素下扩散动力学、非等温析晶动力学以及反应热力学的关系模型，探明钢渣动态化学重构机理；基于提升活性安定性，提出一种在线调控钢渣的新工艺技术。研究成果将充分利用熔融钢渣显热，提供一种崭新的钢渣高效利用的途径，为冶金渣建材化高效应用提供理论基础。

针对钢渣化学组成波动大、胶凝活性低和安定性差等严重制约钢渣高效资源利用的问题。本项目利用熔融钢渣显热，通过向熔融钢渣中掺加调质组分进行在线重构，以提升钢渣胶凝活性和安定性，实现资源与能源协调高效利用。研究从调质依据、调质参数、调制机理、在线重构四方面取得研究成果。.首先以硅酸盐水泥相图钙硅比和硅铝比为目标值、以及水泥熟料三率值（石灰饱和系数KH值、硅率和铝率）作为调质依据，研究了化学组成、重构制度参数等对重构钢渣胶凝活性和安定性的影响规律，研究结果表明这两种调质依据均可以科学合理指导调质，并且以KH值方式更为合适；.二是调质参数研究结果表明当重构钢渣C/S为2.70，S/A为5.79，重构温度1400℃、保温时间30min、水淬急冷制度下，其胶凝活性指数达到97.29%，安定性良好。KH为0.97为最佳值，胶凝活性指数达到98.07%，安定性良好。添加CaF2和CaSO4矿化剂有利于进一步提高钢渣胶凝活性和安定性；基于配方和性能目标，建立了GRNN神经网络模型，为钢渣调质提供配方优化方案。.三是明确了钢渣重构的机理是随着CaO含量增加，促进RO相分解，首先生成MgFe2O4以致降低f-MgO；CaO含量继续增大，优先生成C2F、C4AF等铁铝酸盐矿物，然后硅酸盐矿物生成量提高消耗f-CaO，最终导致MgFe2O4形成量降低，导致MgO释出，但铁铝酸盐矿物增加促进玻璃相生成进而实现微区包裹MgO，致使重构钢渣整体的f-MgO含量降低。项目创新性地发现RO相分解产生的MgO在不同调质条件下会有不同的走向。.四是为解决在线重构的高温混匀瓶颈问题，研究了内部引气对重构钢渣胶凝活性和安定性的影响规律，得出CaCO3掺量不应超过16%，Na2CO3最佳掺量为0.85%，Na2CO3均混效果优于CaCO3。利用低温水模方法模拟分析了外部引气均混手段对重构钢渣粘度、扩散特性的影响规律，建立了重构钢渣扩散动力学模型。利用高温升降炉模拟钢渣在线重构的研究结果表明，采用预热调质组分加入熔融钢渣中的重构工艺能够有效增加重构钢渣胶凝活性和安定性。利用萃取RO相的方法，进一步解释钢渣在线重构的机理是SiO2、Al2O3和CaO含量协同作用的结果。