Abstract: The lifetime of refractory materials is critical for copper melting furnaces. In response to the leakage alarms at the slag-melt interface, the chemical reactions occurring among slag, melt and refractory were first simulated. Subsequently, the elemental distribution and phase composition of refractory eroded areas were analyzed, progressing from the hot face to the cold face. The results show that complex chemical reactions occur between refractory used in copper melting furnace (with Al₂O₃ and MgAl₂O₄ as main phases) and slag (containing C, Cu₂O, Cu, SiO₂, FePO₄, Ca₃(PO₄)₂, etc). Four distinct corrosion zones are formed from the hot face to the cold face: the slag adherence zone (where Cu/FePO₄ liquid phase bind with solid components), the reaction zone (where refractory coexists with reaction products such as Cu/FePO₄ liquid phases, MgSiO₄ and AlPO₄), the copper infiltration zone (where Cu liquid penetrates refractory) and the unreacted zone (original refractory). Based on the corrosion mechanism, improvement strategies are proposed, including controlling the content of externally introduced impurity elements (such as Fe, Ca, Si), optimizing the furnace dismantling and startup processes to reduce lining defects, increasing the TiO₂ content, and avoiding mechanical damage to the lining. This study provides industrial recommendations for extending the lifetime of copper smelting furnace.

Key words: refractory, leak furnace, MgAl₂O₄, Al₂O₃, calcium phosphate, aluminum phosphate