Effects of Atmospheric Conditions on Slag Corrosion Resistance of Lightweight Al2O3-MgO Castables

By adopting dynamic induction furnace corrosion test, the corrosion mechanism of lightweight Al2O3-MgO castable with different environmental oxygen partial pressure was investigated through macro- and micro-analysis, XRD and thermodynamic simulation. The atmospheric condition was set to P(O2) = 0.21 atm or P(Ar) = 1.0 atm. The attained results showed that a reduced slag corrosion but intensified slag penetration happened at low environmental oxygen partial pressure condition. With P(O2) = 0.21atm, Mn and Fe in slag were present in the form of divalent and/or trivalent cations and were incorporated into spinel to form MnFe2O4 solutions and MgAl2O4 solutions during corrosion process. Since Fe, Mn ions are largely consumed, liquid with high viscosity formed and the continuing infiltration was suppressed. Under P(Ar) =1.0 atm, corrosion on castable aggregates was significantly weakened, and the reaction products under this condition are mainly MgAl2O4 and CA6.

Modeling and experiment of slag corrosion on the lightweight alumina refractory with static magnetic field facing green metallurgy

Electromagnetic field is applied widely in metallurgy and other high temperature processes, and affects the behavior of melts. The lightweight alumina based carbon free refractory is of importance for energy-saving, consumption reduction and high quality steel production, and the slag corrosion resistance is significant concerning its service life. Does electromagnetic field control the slag corrosion behavior on the lightweight alumina refractory? In this paper, a multi-field coupled model was established to describe the slag corrosion process in an electromagnetic field. The mathematical modeling in combination of experiments was applied to clarify slag corrosion behavior of lightweight alumina refractory in static magnetic field. The simulation results agree with that of the experiments, which means the proposed model is promising for slag corrosion modeling. The results show that the combination of the slag properties change, and electromagnetic damping caused by MHD (magnetohydrodynamics) effect can enhance the slag corrosion resistance by inhibiting slag penetration and promoting formation of a directional isolation layer, and be beneficial to high-quality clean steel production.

Effect of ZrO2 Additive on the Properties of MgO-Cr2O3 Refractory Used for RH Degasser

To improve the properties and RH degasser slag corrosion resistance of magnesia-chrome refractory, the effect of the addition of ZrO2 was investigated. The results showed that the presence ZrO2 additive can densify the magnesia-chrome samples due to promotion of grain boundary activities and ultimately direct bond formation, which improved the high temperature mechanical properties and corrosion resistance. The results also indicated that in the RH degasser slag system with a high ratio of calcia to silica, the slag resistance behavior of magnesia-chrome composite added ZrO2 could be described as follows: the ZrO2 reacts with CaO to form the calcium zirconate compound which is densification lay and simultaneously, could increase corrosion resistance performance by blinding pore and thickening slag viscosity. Therefore, it is expected to be the major reason for the ZrO2 enhanced corrosion resistance behavior observed for magnesia-chrome refractory.

Corrosion Resistance Mechanism of MgO-ZrO2 Brick in RH Degasser Slag

Slag corrosion resistance behavior of MgO-ZrO2 refractory was investigated in this work. The results indicated that in the non-oriented electric steel slag system with a high ratio of calcia to silica, the slag resistance behavior of MgO-ZrO2 composite could be described as follows: the ZrO2 reacts with CaO forming the calcium zirconate compound which is densification encapsulating periclase lay. However, in the oriented electric steel slag system with a high concentration of silica and the low ratio value of calcia to silica, the slag corrosion resistance behavior of MgO-ZrO2 composite is different. The ZrO2 would react with CaO forming the calcium zirconate and simultaneously, one more product C2S as well. C2S has double response of strength and could increase corrosion resistance performance by blinding pore and thickening slag viscosity. Therefore, it is expected to be the major reason for the enhanced corrosion resistance behavior observed for MgO-ZrO2 refractory.