低碳超低碳耐火材料碳结构调控机理研究

With the technical advancement in iron and steel industry and the acquirement for high performance and low pollution carbon-containing refractories when high quality steel is melted, low carbon and ultra-low carbon refractories have been paid more and more attention. The research about low carbon refractories is increased gradually, but these research are only focused on composite additives, fine graphite, nano technology, matrix optimization and et al to improve the properties of carbon-containing refractories. The carbon in the carbon-containing refractories includes components carbon and binding carbon, both of whose crastal structure and micromorphology determine the properties and structure of carbon-containing refractories. So in this study we prepare to research action mechanism of structure changes of component carbon and binding carbon on properties of low carbon and ultra-low carbon refractories. This study will elucidate the mechanism to obtain components carbon with different structure and reveal the relationship between the structure of component carbon and properties and structure of low carbon refractories. It is also clarified that atmosphere composition, temperature, pressure,solvent type and so on will influence the crystal structure and micromorphology of binding carbon. The influence of the carbon structure change on the different system low carbon and ultra-low carbon refractories is also studied. After the research is ended, composition design principle and carbon structure controlling mechanism will be formed for low carbon and ultra-low carbon refractories, which will provide theoretical guidance for developing high performance and low pollution low carbon or ultra-low carbon refractories.

针对钢铁工业技术进步及冶炼高品质钢时对高性能、低污染含碳耐火材料的要求，低碳超低碳耐火材料越来越受到人们的重视。有关低碳耐火材料的研究日益增多，但仅局限于使用复合添加剂、细石墨、纳米技术、基质优化等来实现MgO-C材料性能的提高。含碳耐火材料中碳包括组分碳和结合碳，二者的晶体结构、显微形貌等决定了含碳耐火材料的性能和结构，因此本项目拟研究组分碳和结合碳结构变化对低碳超低碳耐火材料的作用机制，阐明不同结构组分碳的获取机理，揭示组分碳结构与耐火材料性能之间的相关性；探明气氛组成、温度、压力等以及溶剂种类对不同温度热处理、催化后结合碳晶体结构和显微形貌的影响以及对不同体系低碳超低碳耐火材料性能和结构的影响。本研究将形成低碳超低碳耐火材料组成设计原则和碳结构调控理论，为研发高性能、低污染的低碳超低碳耐火材料提供理论指导。

随着连铸技术的发展、环保要求的提高以及洁净钢品质和需求量的上升，含碳耐火材料低碳化势在必行。然而碳含量的降低会直接导致含碳耐火材料抗热震性和抗渣性的下降，需要采取一定的措施来改善低碳含碳材料的结构与性能。含碳耐火材料中碳包括组分碳和结合碳，二者的晶体结构、显微形貌等决定了含碳耐火材料的性能和结构。因此本项目研究了以下内容：①组分碳结构调控及对低碳超低碳耐火材料性能和结构的影响。采用高能量的机械球磨工艺以膨胀石墨和Al2O3微粉为原料，制备得到在Al2O3基质粉体中有较好均匀分散性能、较理想显微形貌及易获得的含纳米碳复合粉体。添加1wt%振动球磨30h得到的含纳米碳复合粉体试样具有最优综合性能。②气氛控制条件下纤维碳或碳纳米管在低碳含碳材料中的原位生成。研究发现，催化剂对酚醛树脂热处理后的炭结构有显著影响，合适的催化剂及其添加量能使树脂碳中原位生长出碳纤维/管，碳纤维/管或片状碳的生长主要按“VLS”机理进行。添加催化剂可以改善低碳铝碳耐火材料性能，尤其是添加硝酸镍后低碳铝碳试样抗热震性得到显著的改善，强度保持率达65%。③溶剂对结合碳结构以及低碳含碳材料性能的影响。研究发现，溶剂对酚醛树脂固化和热解过程以及残炭率有较大影响，在糠醛体系中形成了新的化学键，残炭率由47.11%提高到56.58%，提高了20%以上。当以糠醛为溶剂时，常温和高温性能都有较大幅度的提高，分别提高10%和36%左右。. 以上研究结果将应用到制备高性能的低碳功能耐火材料中，对洁净钢的品质提升有极大的帮助。