How to select refractory castables for various components of an aluminum melting furnace

There are many types of aluminum melting furnaces. Let’s take the most common rectangular furnace as an example. A rectangular furnace’s overall structure primarily includes the furnace roof, upper furnace wall, furnace door, furnace bottom, lower furnace wall, furnace door frame and surrounding area, as well as the burner and burner. These components operate in different environments and temperatures, so the choice of castables is necessarily different. Furthermore, the aluminum melt itself is a highly reactive and permeable medium. Therefore, the castable selected for the working layer must prevent aluminum melt from penetrating the furnace while also minimizing impurities in the melt.

① Furnace Roof: The furnace roof is primarily divided into the furnace roof insulation layer and the furnace roof working layer. The working layer is in direct contact with the flames, resulting in very high temperatures. The insulation layer primarily insulates the furnace to prevent rapid heat loss. Therefore, the furnace roof working layer is primarily made of heavy castables, while the furnace roof insulation layer is primarily made of lightweight insulating castables.

② Upper Furnace Wall: The upper furnace wall is primarily divided into the upper furnace wall working layer and the upper furnace wall insulation layer. Similar to the furnace roof working layer, the castable selection primarily uses heavy castables for the working layer and lightweight insulating castables for the insulation layer.

③ Furnace Bottom and Lower Furnace Wall: The furnace bottom and lower furnace wall come into contact not only with the flame but also with molten aluminum. Therefore, to withstand high temperatures and the penetration of molten aluminum, the castable selection primarily focuses on non-stick aluminum castables, impermeable castables, and lightweight insulating castables. These are used for the furnace bottom working layer, the furnace bottom impermeable layer, and the furnace bottom insulation layer, respectively.

④ Furnace Door: The furnace door is where raw materials enter and exit, so it is subject to frequent friction. To prevent damage from prolonged friction and flame damage to the furnace door, lightweight insulating castables and high-strength, wear-resistant castables are primarily selected.

⑤ Furnace door frame and surrounding areas: Steel fiber self-flowing high-temperature, high-strength, wear-resistant castables are primarily used to enhance the structural strength of the furnace door.

⑥ Burner and blasting nozzle: The burner and blasting nozzle areas experience higher temperatures, and raw materials are frequently transported through these areas. Therefore, self-flowing high-temperature, high-strength, wear-resistant castables are primarily used as castables.