Magnesia carbon bricks which we normally use have black shiny appearance with slippery surface, leaving carbon on touch.
Is it possible to get such appearance after curing only i.e. after holding at 250C or above, or after curing + pyrolysis , or we must need to go for impregnation step in order to have such an appearance of brick, ready for lining.
If we go through the history and evolution of Magnesia Carbon Bricks, we will find the first Mag Carbon bricks were made by tar impregnating the Burnt Magneia Bricks. But now a days Magnesia Carbon bricks are no more fired and made by mixing Graphite as the source of Carbon, DBM or Fused magnesite or combination and pressed at ghigh pressure after mixing with PF Resin. By this method higher % of C can be introduced at a lesser cost and with much faster cycle time.
Tar impregnation is some thing done after pressing and curing the resin bonded bricks. Its main purpose is to remove porosity created in the process of curing, and also an attempt to increase carbon content of the brick surface.
By my concern is that, whether it is a necessary step or can avoided, if we don't have any setup to perform such treatment.
For most applications where MgO-C brick are used it is not necessary and is actually an exception. Some companies have applied this type of brick in very high wear areas of BOF vessels (trunnion areas). After curing most MgO-C bricks have porosity values of 4-6% so the amount of tar that you can actually get into the brick is limited.
With addition of graphite,solid resin,liquid resin and pitch powder in magnesia carbon bricks,we already achieve low porosity.Therefore tar impregnation is not necessary for magnesia carbon bricks.
Now a days, only magnesia carbon based EAF/EBT Taphole sleeves are tar impregnated for better performance.
Is it possible to get such appearance after curing only i.e. after holding at 250C or above, or after curing + pyrolysis , or we must need to go for impregnation step in order to have such an appearance of brick, ready for lining.
If we go through the history and evolution of Magnesia Carbon Bricks, we will find the first Mag Carbon bricks were made by tar impregnating the Burnt Magneia Bricks. But now a days Magnesia Carbon bricks are no more fired and made by mixing Graphite as the source of Carbon, DBM or Fused magnesite or combination and pressed at ghigh pressure after mixing with PF Resin. By this method higher % of C can be introduced at a lesser cost and with much faster cycle time.
Tar impregnation is some thing done after pressing and curing the resin bonded bricks. Its main purpose is to remove porosity created in the process of curing, and also an attempt to increase carbon content of the brick surface.
By my concern is that, whether it is a necessary step or can avoided, if we don't have any setup to perform such treatment.
For most applications where MgO-C brick are used it is not necessary and is actually an exception. Some companies have applied this type of brick in very high wear areas of BOF vessels (trunnion areas). After curing most MgO-C bricks have porosity values of 4-6% so the amount of tar that you can actually get into the brick is limited.
With addition of graphite,solid resin,liquid resin and pitch powder in magnesia carbon bricks,we already achieve low porosity.Therefore tar impregnation is not necessary for magnesia carbon bricks.
Now a days, only magnesia carbon based EAF/EBT Taphole sleeves are tar impregnated for better performance.
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