The blast furnaces of metallurgy are lined by carbon-based ceramic refractories. They are known for their high resistance to corrosion and molten iron erosion, low wettability against steel and slag melts, and high mechanical strength at elevated temperatures. It is oxidation that can result in the destruction of the refractory material and its properties. To improve their oxidation resistance, manufacturing methods and conditions must be optimized.
This requires that you understand the mechanisms determining the oxidation behaviors of the carbon refractories. This paper presents a research on the properties of heat-treated carbon refractories under various conditions. Results show that metallic silicon and alumina particulates can improve the resistance to oxidation of carbon-based ceramics.
The raw materials used to produce carbon refractory are coal coke, anthracite and graphite that have been heat treated with binding agent of coal tar pitch. This quality furnace-refractory material contains over 80% carbon fixed and can be used as the lining for blast furnaces' bottom, hearth or lower stack.
In order to avoid carbon refractory degrading due to oxidation it is necessary to maintain the lowest possible volatile components, sulfur levels and moisture contents in the anthracite. The method of heat-treatment that is most suitable for carbon refractories is to use a rotary kiln where the anthracite is heated at 1000
In order to manufacture large-sized carbon refractories for blast furnaces, it is important to increase the particle size of the aggregate and to add a high-grade binder. In order to do so, a coarse-grain artificial aggregate can be made by mixing flake graphite with alumina and metallic silicon. The compound is kneaded into a large carbon refractory that can be used as an lining material for blast furnace basins.
In this article, the research shows that carbon refractories made of alumina are better than their counterparts without alumina in resisting molten-iron erosion. In addition to its higher mechanical properties, the alumina refractory exhibits better thermal-shock resistance, less linear shrinkage and is more resistant to heavy loads. These results indicate that adding alumina particle to carbon-based ceramic refractory could significantly prolong its life. It will be beneficial to the metal industry, and reduce costs for refractory. It is possible because the alumina refractory can withstand damage caused by the hot spots of the arc-furnace. As a result, the number of repair and maintenance tasks can be significantly reduced.
English
Write a Message