MICROSTRUCTURAL AND THERMAL PROPERTY CHANGES OF CASTABLES AFTER CORROSION WITH BLAST FURNACE SLAG AT DIFFERENT CONDITIONS

摘要

Slags from iron and steel production are importantbyproduct, which can be processed to be used for instance inroad construction or as fertilizer in agriculture. For applicationin the production of cement, amorphous solidified blast furnaceslag is used, also referred to as slag sand. The blast furnace slagexhibits a tapping temperature up to 1700°C, however thisstored thermal energy cannot be retrieved yet. In order todevelop industrial facility for the heat recovery, the selection ofcorrosion resistant refractory materials is crucial.Different refractory bricks and castable materials weretested in contact of molten blast furnace slag in order to describethe mechanisms of corrosion and their suitability for theapplication process. The first material was an oxide refractorycomposed mainly of Andalusite, while the second one was SiCbased. A thermodynamic model, by using the software packageFactSage, was worked out and applied on the differentrefractory and slag compositions to predict phase formation andcorrosion. The microstructural properties of the brick andmonolithic samples were characterized after firing by means ofporosimetry and Scanning Electron Microscopy (SEM)examinations. Dynamic corrosion tests have been performed onthe refractory materials, in particular finger test methodology asdescribed in the European standard (DIN 15418). Dissolutionand erosion behavior have been examined. Subsequent to themacroscopic evaluation performed on the infiltrated samples,microscopic characterization and structural changes of thecorroded microstructure have been carried out with SEM/EDSand XRD.