Attack Under Load of Tempered Tar/Pitch-Bonded Egyptian Dolomite by BOF Slag

Different tar/pitch bonded Egyptian dolomite and dolomite-magnesite mixtures with magnesia content ranging between 30-50% to replace dolomite, were prepared. Three different types of tars with different pitch content (I, II and III) were used. The mixtures were moulded, tempered and attacked by BOF slag at temperatures up to 1700°C. The attacking process was carried out under load 3.5-5kg/cm2 as a new method to study the deformation of the refractory to indicate the slag attack. The results showed that tar/pitch (III) with 80% pitch can resist load up to 4kg/cm2 when attacked by BOF slag. At the same time, increasing the magnesia content of the tar/pitch (III)-bonded dolomite up to 50% magnesia can increase its softening under load up to 5kg/cm2. The erect of the slag composition on the best-obtained mixture of the tar/pitch (III)-bonded dolomite-magnesite refractory was studied. Tempered tar/pitch (III)-bonded Egyptian dolomite was attacked by synthetic basic slag containing different iron oxide content. It was found that the increase of the iron oxide content of the slag is the main factor responsible for the attacking of refractories. It was concluded from this study that, this test could be considered as beneficial test because it simulates the application of the refractories in the furnace. It also can be used as fast criteria for the determination of the resistance of the refractories for slag attacking and can provide the manufacturer and the consumer valuable data about the behavior under load.