This article describes the future research directions of magnesia-carbon bricks.
Keywords: magnesia carbon brick; development
Magnesia-carbon bricks will continue to develop in the field of iron and steel metallurgy due to their excellent properties. To this end, through the summary and analysis of its research status, the next development direction and focus of magnesia-carbon bricks are extracted: (1) Traditional magnesia-carbon bricks Through the design and optimization of particle gradation, magnesia microstructure and overall structure of magnesia carbon bricks, its performance can be continued to be improved or fully utilized. (2) Research on high-performance antioxidants, especially the research and synthesis of non-metallic antioxidants with high oxygen affinity, low expansion and low stress, will be an important way to improve the performance of magnesia carbon bricks in the future. (3) In the process of low carbonization of magnesia carbon bricks, the miniaturization and crystallization of carbonaceous components will continue to receive attention and development as a key way to effectively improve its structural stress and resistance to slag permeability.
Refined research on traditional magnesia carbon bricks
Although magnesia-carbon bricks have been developed for more than 30 years and are constantly being researched and improved, the damage and working surface structure of magnesia-carbon bricks during use show that magnesia-carbon bricks have not fully utilized their respective components. The performance of LF refining slag line magnesia carbon bricks has not achieved the maximum use effect; the exposed magnesia particles, extremely low strength and loose structure on the working surface of LF refining slag line magnesia carbon bricks illustrate this point. Through years of follow-up research, it has been found that the magnesia carbon bricks used in the LF refining ladle slag line have different magnesia crystallization conditions, impurity distribution, grades and overall structural matching. The service life of the magnesia carbon bricks is completely different. The working surface structure Also very different. Therefore, how to conduct refined research on the research status and development trends of magnesia-carbon bricks in terms of raw materials, inter-crystal and inter-particle interface structures, particle gradation, etc., so that magnesia-carbon bricks have excellent multi-dimensional properties such as structure, composition and stress. Ground matching is very important for the upgrading and large-span innovation of traditional magnesia carbon bricks. It will also be one of the key research directions for greatly improving the performance of magnesia carbon bricks.
High performance and multifunctional antioxidant
Antioxidants are a very important component of carbon composite materials, and their performance is directly related to the performance of magnesia carbon bricks; the emergence of high-performance antioxidants will greatly improve the performance of magnesia carbon bricks or promote the upgrading of magnesia carbon bricks. , Therefore, how to prepare antioxidants with high antioxidant properties and high temperature strength through composition, structure control, new processes and new technologies will be one of the main development directions of magnesia carbon bricks in the future. For low-carbon magnesia-carbon bricks, in view of their low carbon content and special structure, their antioxidants should not only have the antioxidant function of ordinary magnesia-carbon bricks, but also have their volume stability and oxidation resistance at high temperatures. The volume stability of the reaction process between the product and the matrix, etc., is what many conventional antioxidants currently lack. Research has been conducted on the anti-oxidation properties of carbides such as AlSiC, AI℃, and Al4C3N. It is found that this type of material not only has good anti-oxidant functions, but also can promote the densification of the magnesia carbon brick structure during the oxidation process. It also has certain resistance to wetting by molten steel and slag, which is very important for low carbon magnesia carbon bricks. Therefore, for low-carbon magnesia-carbon bricks, how to prepare new non-metallic antioxidants through structure and component design, etc., to achieve graphite-like functions with resistance to slag permeability while preventing oxidation, will be a new topic. The most promising research direction for a new generation of antioxidants.
Research on low carbon magnesia carbon brick binder
The carbon content of traditional magnesia-carbon bricks is high, and it can form a continuous carbon network and does not require high binders; while the carbon content of low-carbon magnesia-carbon bricks is low, and it is difficult to form a connection network. This is also the reason for low-carbon magnesia-carbon bricks. The reason why the performance is relatively poor compared with traditional magnesia carbon bricks. Therefore, the binder used for low-carbon magnesia-carbon bricks should not only have the characteristics of traditional binders, but also have its own special properties. The ideal binder for low-carbon magnesia-carbon bricks should be easy to distribute evenly, and the carbonized carbon component should have a certain stability. Therefore, there is room for further research on the molecular structure, branched chain structure, viscosity, graphitization ability, and organic combination of carbonized structure and anti-oxidation components of the binder to realize its role as a source of molding and strength of magnesia carbon bricks. At the same time, the antioxidant capacity of the carbon-bound network is enhanced, or a certain stress buffering capacity is given to the carbon-bound network.
Stress decomposition and structural optimization of low carbon magnesia carbon bricks
Due to the high graphite content of traditional magnesia-carbon bricks, the structural stress can be ignored; while for low-carbon magnesia-carbon bricks, it cannot be ignored, which has not attracted attention in the current research on low-carbon magnesia-carbon bricks. The expansion coefficient of magnesia particles is very large compared to graphite, which is also the fundamental reason for the large structural stress of low carbon magnesia carbon bricks. Therefore, how to alleviate the expansion stress of particles through matching design of particle gradation, particle interface structure, matrix structure, etc., and then achieve multi-scale matching of low carbon magnesium carbon bricks in structure, composition and stress, will be the key to low carbon magnesium carbon bricks. The direction of in-depth research on stress decomposition of bricks. Among them, the matrix is responsible for resisting the penetration and erosion of slag and buffering the stress of particle expansion. It has a greater impact on the performance of low-carbon magnesia-carbon bricks and is one of the main directions for stress relief and structural optimization. Matrix optimization can carry out refined matching from the aspects of phase distribution, fine powder particle size, interface reaction and pore structure of the matrix, so that the matrix can fully exert its performance. This is also an area that is currently ignored and unrecognized in the research of low carbon magnesia carbon bricks.