Dissolution of Al2O3–C bricks in 45 wt% CaO-45 wt% SiO2-x wt% CaF2-(10-x) wt% Na2O slag.

The dissolution of Al 2 O 3 –C refractories in 45 wt% CaO-45 wt% SiO 2 -x wt% CaF 2 -(10-x) wt% Na 2 O slag was explored by the static test and thermodynamic calculation. The results show that the severe slag penetration into refractories occurs after corrosion test. With the gradual replacement of CaF 2 in slag by Na 2 O, lots of pores are found in the slag phase near the refractory/slag interface due to the formation of gaseous phase from the reaction between Na 2 O in slag and C in refractories. Compared with the slag without Na 2 O, the slag bearing 5 wt% Na 2 O does not accelerate the dissolution of refractory into slag. The possible reason is that the reaction between CaF 2 in slag and Al 2 O 3 in bricks is inhibited due to the replacement of CaF 2 in slag by Na 2 O. The dissolution of Al 2 O 3 –C refractories is faster in the slag bearing 10 wt% Na 2 O than that in the slag bearing 5 wt% Na 2 O, due to the severer Na 2 O volatilization from the reduction of Na 2 O in slag by C in refractories, which accelerates the renewal rate of boundary layer between refractories and slag phase. The results indicate that replacing part of CaF 2 in mold slag with moderate amount of Na 2 O does not aggravate the corrosion of submerged entry nozzle consisting of Al 2 O 3 –C based refractories. [ABSTRACT FROM AUTHOR]