Corrosion behavior of Al_(2)O_(3)-C bricks in MnO-containing mold slag

In order to explore the corrosion mechanism of Al_(2)O_(3)-C refractories in the mold flux bearing MnO,the immersion test of Al_(2)O_(3)-C refractories in CaO-SiO2-CaF2-MnO slag with different MnO contents was carried out at 1550℃.The results show that Mn particles were observed in the slag after experiment,due to the reduction of MnO by graphite in refractories.Large amounts of graphite were observed at the interface between refractories and slag,indicating that the oxidation of graphite is limited by the poor contact between graphite and molten slag.Therefore,the oxidation of graphite is not the main cause of damage to refractories.A small quantity of CaO·2Al_(2)O_(3)(CA_(2))and CaO·6Al_(2)O_(3)(CA_(6))adjacent to Al_(2)O_(3) grain was detected at the slag/reaction layer interface.CA_(2) and CA_(6) possess relatively high melting points,which is beneficial to hindering the further penetration of slag.However,the dissolution of Al_(2)O_(3) into slag is still the main cause for refractories damage.The increase in the MnO content of mold slag decreases the viscosity and then results in the severe corrosion of Al_(2)O_(3)-C bricks.