Review of Oxidation Resistance Technology of Carbon-containing Refractories

Carbon-containing refractories prepared by compounding MgO or Al2O3 with flake graphite have excellent thermal shock resistance and slag corrosion resistance. It is widely used in submersed nozzle, long nozzle, monolithic Stopper, slide gates and other functional refractories product for flow controlling and steel cleaning, as well as basic oxygen furnaces, electric furnaces, steel ladles and smelting industrial furnace lining. At the same time, as steel metallurgical tend to be more efficient and intelligent, higher requirements are placed on the slag corrosion resistance and thermal shock resistance of carbon-containing refractories. The damage of carbon-containing refractories often starts from the oxidation of graphite. The easily oxidized carbon not only expend flake graphite resources to release greenhouse gases, but also decrease the pro-perties of carbon-containing refractories and curtail the service life. Therefore, the development of oxidation resistance technology of carbon-containing refractories has important significance for improving the quality and efficiency of metallurgy industry and environmental protection. However, the composition of the raw materials of the carbon-containing refractories is complicated, and the performances are mutually restric-ted during use. While improving theoxidation resistance, other properties of the carbon-containing refractories are reduced. Therefore, in addition to the optimization of the oxidation resistance by adjusting the content and grain size of different antioxidants, researchers have mainly explored the antioxidant composite and the microstructure evolution of carbon-containing refractories, improve slag corrosion resistance and mechanical properties. According to the oxidative damage mechanism of carbon-containing refractories, the addition of antioxidant is still the most commonly used oxidation resistant technology for carbon-containing refractories. In addition to the formation of metal oxides and carbides to prevent the oxidation of carbon-containing refractory materials, metal antioxidants can also improve the mechanical properties and slag corrosion resistance of carbon-containing refractories by solid state reaction. The transition metals and metal alloys. As an antioxidant, it also has catalytic pyrolytic carbon graphitization and promotes the formation of carbide whiskers. In addition to the common silicon carbide and boron carbide, the MAX phase and the complex compounds prepared by Al with carbides not only have excellent oxidation resistance, but also can avoid material cracking by prevent the hydration of metal carbides. Boron-containing oxides can not only form a dense oxide layer to slow the penetration of oxygen, but also make it easier to form magnesia-alumina spinel through ion migration. In addition, nano antioxidants and composite powders antioxidants are easier to disperse in the matrix of carbon-containing refractories to form a even microstructure to improve comprehensive performance. This review summarizes the oxidative damage mechanism of carbon-containing refractories; mainly analyzes the current research status of three types of antioxidants, including metals, carbides and boron-containing oxides, and focuses on the research progress of antioxidants in the reaction mechanism and microstructure evolution. Finally, a new research direction of oxidation resistance technology for carbon-containing refractories is proposed. © 2021, Materials Review Magazine. All right reserved.