How to improve the lifespan of refractory materials in aluminum melting furnaces

When selecting refractory materials for aluminum smelting furnaces, various factors should be considered, including the refractory’s strength, porosity and pore distribution, and the addition of anti-aluminum wetting agents.

① Use Raw Materials with High Corrosion Resistance

The importance of Al2O3 content in refractory materials for resisting molten aluminum corrosion has been proven in practice. In fact, increasing Al2O3 content reduces the reactivity of the refractory with molten aluminum, which means its resistance to aluminum penetration and corrosion is enhanced. This is primarily due to Al2O3’s high melting point and chemical stability, making it effective in resisting molten aluminum corrosion. Therefore, the Al2O3 content of refractory materials used in aluminum melting furnace baths should be above 75%.

To achieve this requirement, the raw material ratio and quality must be strictly controlled during refractory production. Furthermore, the use of advanced preparation techniques and optimized firing schedules are key factors in ensuring an Al2O3 content above 75%.

② Improving the Anti-Aluminum Wetting Properties of Refractory Materials

The impact of molten aluminum permeability on refractory materials is a key issue that requires significant attention. Because molten aluminum has high permeability, it can easily penetrate the pores and crevices of refractory materials, potentially damaging and eroding the refractory structure.

To prevent refractory penetration by molten aluminum, the primary task is to address the wetting of the castable by the molten aluminum. Wettability refers to the ability of a liquid to adhere to a solid surface. If molten aluminum can wet the surface of a refractory, it can easily penetrate into the interior. Therefore, to prevent molten aluminum from penetrating and eroding the refractory, it is essential to ensure that the castable is not wetted by the molten aluminum.

③ Reduce Porosity

The lower the porosity of the refractory, the less likely it is that molten aluminum will penetrate the interior, thus reducing erosion.

④ Improve the strength and thermal shock resistance of the refractory.

During the aluminum melting process, the addition of aluminum ingots and scrap can impact the melt pool walls, and the slag scraper can damage the inner walls of the melt pool. Furthermore, frequent opening and closing of the furnace door causes temperature fluctuations, which can cause thermal damage to the refractory. These factors accelerate the wear and deterioration of the refractory. Therefore, improving the strength and thermal shock resistance of refractory materials is particularly important for extending their service life.

When selecting refractory materials for aluminum smelting furnaces, factors such as strength, porosity and pore distribution, and thermal stability should be comprehensively considered. By rationally selecting and using high-quality refractory materials, the service life of aluminum smelting furnaces can be effectively extended, improving production efficiency and economic benefits.