酚醛树脂/三辊差速剥离微纳石墨片及其在低碳MgO/Al2O3-C耐火材料中应用的研究

To satisfy the needs of low-carbonization, high property, and low cost for Lining furnaces to make high grade clean steels, based on the applied patent of invention, this project will perform the basic research on using Three-Roll-Mill with different speeds as key technology to continuously exfoliate flake graphite in the medium of phenolic resin to produce well crystallized-graphite micro/nano platelets (MNGP) with large aspect ratio, which could be further used to develop a new generation of low-carbon MgO/Al2O3-C refractories (MACRs). By accurately controlling the process parameters of Three-Roll-Mill, the graphite flakes will be exfoliated to different extents, forming the submicron thickness (graphite micro-platelets, GMP), nanometric thickness (graphite nano-platelets, GNP) or few atomic-layer thickness (multilayered graphene, MLG) and the exfoliate mechanism will be revealed. Then the preparation technology of low-carbon MACRs containing these three exfoliated-productions in-situ in phenolic resin respectively will be investigated, and the influence law of GMP, GNP and MLG on MACRs’ microstructure, thermal conductivity, strength, resistance to oxidization, thermal shock resistance and corrosion resistance to liquid steel/slag discussed. Thus micro/nano-sized graphite platelets on their functional behavior and optimization mechanisms of properties could be concluded. This research will establish an important theoretical and technical foundation for producing high property-low cost low carbon carbon-containing refractories, and has a great potential to develop the refining technology for clean steel.

本课题针对洁净钢炉外精炼工艺要求的耐火材料低碳化、高性能、低成本的迫切需求，在发明专利的基础上，提出以鳞片石墨为原料、酚醛树脂为介质，通过三辊差速连续剥离技术获得晶态效果好、纵横比大的微纳米石墨薄片，来开发新一代低碳MgO/Al2O3-C耐火材料的应用基础研究。通过对三辊差速剥离过程的精确控制，寻求在酚醛树脂中均匀分散的微米片、纳米片和多层石墨烯三种结构的优化剥离工艺参数并揭示减薄机制；进而研究三种结构的酚醛树脂基微纳米石墨薄片的新型低碳含碳耐火材料的制备技术，探讨剥离后不同结构尺寸的微纳米石墨片对材料的微观结构性质、导热性、强度、抗氧化、抗热震和抗钢水/熔渣侵蚀等性能的影响规律，阐明碳含量在大幅度降低的情况下微纳米石墨薄片在其中的作用行为和性能优化机理。研究工作将为高性能低成本低碳含碳耐火材料的技术进步奠定重要的基础和理论依据，对我国洁净钢精炼技术的发展具有重要推动作用和实际应用价值。

本项目主要针对洁净钢炉外精炼工艺要求的耐火材料低碳化、高性能、低成本的迫切需求，以鳞片石墨为原料、酚醛树脂为介质，通过三辊差速连续剥离技术获得晶态效果好、纵横比大的微纳米石墨薄片，进而开发新一代低碳MgO/Al2O3-C耐火材料。针对项目主要研究内容，对“石墨在酚醛树脂中三辊差速研磨减薄技术”、“石墨减薄后与酚醛树脂的混合物和耐火材料原料的分散与成型技术”、“低碳MgO/Al2O3-C耐火材料的结构设计、力学性能和高温性能调控优化”、“新型低碳MgO/Al2O3-C耐火材料抗洁净钢水（IF钢）/熔渣侵蚀及其相互作用机制”进行了系统的研究。本项目完善了采用在结合剂中直接减薄石墨基低碳含碳耐火材料骨料和细粉的分散与成型固化技术基础理论；获得了微纳石墨薄片在低碳含碳耐火材料强度、抗氧化性能提高的影响规律和性能优化的技术途径；并采用XRD、SEM、EDS等技术手段对制备的低碳含碳耐火材料与洁净钢/熔渣的反应侵蚀界面进行结构和成份的分析，揭示其与服役环境的相互作用、侵蚀机理、性能演变与失效机制，碳含量为2wt%（1.7wt%GNPs和0.3wt.%PF/GNPs）的GNPs的碳源为低碳耐火材料提供了最佳的综合性能。此外，也进行了与本项目相关的其他材料体系的制备与性能研究，并取得了一系列的成果，探究了过渡金属催化氮化制备Sialon及其性能的研究，Y2O3及过渡金属硝酸盐氮化反应催化合成Ce2Si2.5Al0.5O3.5N3.5，熔盐法合成镁铝尖晶石（MA）和碳化钛（TiC）、Ni掺杂Mo2C@C以及纳米花Mo2C的调控及其性能等等。以上研究工作将为高性能低成本低碳含碳耐火材料的技术进步奠定重要的基础和理论依据，对我国洁净钢精炼技术的发展具有重要推动作用和实际应用价值。