Post-mortem characterization of Al2O3-SiC-C refractory castables exposed on the main runner of blast furnaces
DARBAN S. 1, PATAPY C. 1, LACARRIÈRE L. 1, CYR M. 1, CHEVALLIER G. 2, STEPHANE L. 3, PROIETTI A. 3, MONVILLE Y. 4, PRIGENT P. 4
1 Laboratoire Matériaux et Durabilité des Constructions, INSA/UPS Génie Civil, Université de Toulouse, CEDEX 04, 31077 Toulouse, France, Toulouse, France; 2 CIRIMAT, Université de Toulouse, CNRS, Université Toulouse 3 Paul-Sabatier, 118 route de Narbonne, F-31062, Toulouse cedex 9, France, Toulouse, France; 3 Centre de Microcaractérisation Raimond Castaing, UMS 3623, Université de Toulouse, Espace Clément Ader, 3 rue Caroline Aigle, 31400, Toulouse, France, Toulouse, France; 4 TRB - 31 rue Wilson 69150 Decines Charpieu, France, Nesles , France
Post-mortem characterization of Al2O3-SiC-C refractory castables exposed on the main runner of blast furnaces: towards a better understanding of mechanisms of degradation
Sina Darban1, Cédric Patapy1, Laurie Lacarrière1, Martin Cyr1, Geoffroy Chevallier2, Stephane le blond du plouy3, Arnaud Proietti3, Yannick Monville4, Pascal Prigent4
1Laboratoire Matériaux et Durabilité des Constructions, INSA/UPS Génie Civil, Université de Toulouse, CEDEX 04, 31077 Toulouse, France 2CIRIMAT, Université de Toulouse, CNRS, Université Toulouse 3 Paul-Sabatier, 118 route de Narbonne, F-31062, Toulouse cedex 9, France 3Centre de Microcaractérisation Raimond Castaing, UMS 3623, Université de Toulouse, Espace Clément Ader, 3 rue Caroline Aigle, 31400, Toulouse, France 4TRB - 31 rue Wilson 69150 Decines Charpieu, France
Presenting author e-mail: darban@insa-toulouse.fr
During the main runner’s campaign life in blast furnaces, the refractory castables implemented as working lining experienced severe operating conditions: high temperatures (1490~1550 °C) because of the contact with hot metal and slag, suffering erosion, thermal shock, oxidation and corrosion by slag and iron oxide (FeO).
The wear mechanisms related to the slag line and metal line could be an informative way to point out different factors that influence refractory durability in these areas. Post-mortem studies of main runner refractories are essential to classify the failure mechanisms that might imply developments to be applied in the refractory’s formulas, in the maintenance’s process and in the runner’s design. Hence, developing the performance of the leading runner with a longer lifetime and secured casthouse operation is proposed as a final achievement.
This research presents the results of a post-mortem study on the Al2O3-SiC-C (ASC) refractory castables used in the slag line and metal line of the main through runner of blast furnaces. The main runner divides into three different zones: turbulence zone, middle zone, and non-turbulence zone. The highest erosion and physical abrasion of ASC castables are observed on-site in the turbulence zone where the slag and iron drain from the taphole into the runner.
The microstructure of Al2O3-SiC-C castables from slag lines of turbulence zone and none-turbulence zones are characterized by scanning electron microscopy coupled with energy dispersive electron spectroscopy (SEM/EDS). The wear mechanism (erosion/corrosion) of ASC castables by different corrosive mediums (slag and iron) is investigated and discussed. The results showed that, in most cases, the infiltrated slag interacts with oxides. The dissolution of carbon in molten iron leads to the infiltration of iron in the matrix of castables.
The intensive erosion/corrosion in the turbulence zone is attributed to the exposition of runners to the refreshed mixture of slag and iron. Nevertheless, in the non-turbulence zone, the wear rate of ASC castables is less than the turbulence zone due to the dissociation of the mixture of slag and iron.
Keywords: Al2O3-SiC-C castables, corrosion, iron through, SEM, EDS.
Keywords: Al2O3-SiC-C castables, corrosion, iron through, SEM, EDS
