DECARBURIZATION OF IRON MELT BY AN IMMERSED AL2O3-FE2O3 POROUS TUBE

A porous Al2O3-Fe2O3 tube, the inside of which is evacuated, is used t o decarburize molten iron. Effects of inside pressure and Fe2O3 conten t of the porous tube, initial carbon content of the melt and melt temp erature on the decarburization rate are investigated. Evacuating the i nside of the tube reduces the partial pressure of CO at the tube-melt interface and enhances the decarburization reaction. However, in the c ase of lower initial carbon content of the melt, liquid slag is formed at the surface of higher Fe2O3 content Tube, and sucked into its pore . Penetration of the liquid slag into the tube reduces the thermal str ength and leads to the tube deformation. As a result, the gas permeabi lity of the tube is decreased, and the decarburization rate becomes lo wer. The apparent decarburization rate constant (apparent first-order rate constant) for the non-deformed tube increases with increasing Fe2 O3 content and decreasing inside pressure of the tube. At higher carbo n contents, the tube is not severely deformed, but the effect of evacu ation on the decarburization rate is little due to formation of large amount of CO (or CO boiling). The apparent decarburization rate consta nt decreases with increasing initial carbon content, and hence the rat e is presumed to be controlled mainly by oxygen supply from the tube. The apparent activation energy for the decarburization reaction is 72. 5 kcal/mol.