a ladle.....

there it is.

just after deslagging, ready to go back to ladle preparation bay for lining, purging plugs, tapping nozzles and slidegate plates checking.

the rings show the working lining of a ladle and the top freeboard and slaglining too.

since basic slags are made at LF in this plant, this inner lining is made of basic bricks so that the attack of basic slag on the lining will be minimal and least aggressive.

what makes the basic bricks basic?

well, when we take a look at the extended basicity formula ( CaO+MgO+MnO) / (SiO2+Al2O3+FeO), it can be easily understood the molecules of the numerator contribute to basic nature while those from the denominator make the refractories acidic.

so it can be inferred, the ladle inner working lining should be made of mainly one or more of the molecules from the numerator to make it basic.

ladle and tundish inner, working linings are made of MgO bricks while the backup linings are made of Al2O3  bricks.

bricks at the bottom, metal-lining generally give a life of around 120-150 heats while the slag lining bricks are debricked and relined after half of that number.

once a ladle is put into service, slag-lining brickes are changed twice in a campaign while metal-lining bricks are changed once in that life of around 120-150 heats. after completion of that campaign, entire working lining (bricks of slag as well as metal lining) is stripped off and relined after sufficient inspection or patching as necessary.

purging plugs give a life of around 30 heats while the slidegate plates hardly give 4 heats life. outer nozzles also get changed along with the bottom plates while inner nozzles give a life of 5 or 6 heats in general. but everything is subjected to REAL TIME, ACTUAL condition of the ladle; best is, NOT TO GIVE TAKE ANY CHANCE when there is even a little doubt, since anything untoward may cost huge losses than changing the doubtful, suspected part of the ladle.