Abstract: The corrosion behavior of MgO-C refractories in molten slag was investigated under the applied voltage using MgO-C brick and molybdenum as the cathode and anode, respectively. The results show that the deposition potential of Si is about -6.1 V in the slag of CaO-SiO2-Al2O3 system and -1.25 V of Fe, -5.85 V of Si in the CaO-SiO2-Fe2O3 system, respectively. When the voltage is applied between the cathode and anode, ions, such as SiO42- and Fe2+, move to the cathode and aggregate around the cathode. When the voltage applied is lower than the decomposition voltage of slag, the aggregated ions lead to an increase of viscosity of slag around the cathode, which decays the diffusion of slag toward the MgO-C refractories and then leads to a decrease of penetration depth. When the applied voltage is larger than the decomposition voltage of slag, liquid Si or Fe is produced in the role of applied voltage, which causes the shift of slag composition toward the high melting products (Ca2SiO4, MgAl2O4). The formation of high melting product layer is supposed to be a good physical and chemical protection for the refractory because they hinder the direct contact between the slag and the refractory. The type of electrodeposit products is closely related to slag compositions, for example, Ca2SiO4 formed in CaO-SiO2-Al2O3 system and MgAl2O4 formed in CaO-SiO2-Al2O3-MgO system.
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2017, Vol. 31 
