Preparation of Ceramic-Bonded Carbon Block for Blast Furnace

Traditional carbon blocks for blast furnaces are mainly produced with electrically calcined anthracite owing to its good hot metal corrosion resistance. However, this kind of material shows low thermal conductivity and does not meet the demands for cooling of the hearth and the bottom of blast furnaces. In this article, a new kind of a high-performance carbon block has been prepared via ceramic-bonded carbon (CBC) technology in a coke bed at 1673 K (1400 degrees C) using artificial graphite aggregate, alumina, metallic aluminum, and silicon powders as starting materials. The results showed that artificial graphite aggregates were strongly bonded by the three-dimensional network of ceramic phases in carbon blocks. In this case, the good resistance of the CBC blocks against erosion/corrosion by the hot metal is provided by the ceramic matrix and the high thermal conductivity by the graphite aggregates. The microstructure of this carbon block resembles that of CBC composites with a mean pore size of less than 0.1 mu m, and up to 90 pct of the porosity shows a pore size <1 mu m. Its thermal conductivity is higher than 30 W.m(-1).K-1 [293 K (20 degrees C)]. Meanwhile, its hot metal corrosion resistance is better than that of traditional carbon blocks. (C) The Minerals, Metals & Materials Society and ASM International 2013