Selection of Refractory Materials for Aluminum Smelting Furnace Lining

There are three main types of aluminum smelting furnaces: reverberatory furnaces, rotary furnaces, and induction furnaces (core induction furnaces and coreless induction furnaces). The furnace lining is mostly constructed with clay bricks, high-alumina refractory bricks, and corundum mullite bricks. High-alumina refractory castables and refractory plastics can also be used for casting or ramming.

Refractory Materials for Aluminum Smelting Furnace Linings

Reverberatory furnace linings are classified into fixed and tilting types. For fixed reverberatory furnaces, the insulation layer uses refractory fiber felt or lightweight clay bricks. The working layer above the molten pool uses clay bricks, or high-alumina castable precast blocks or refractory plastic ramming can be used. The working layer of the molten pool uses grade I high-alumina bricks, or 75% high-alumina low-cement castable. Mullite bricks or corundum bricks can be used for the working lining in high-temperature areas. Due to severe corrosion, silicon carbide bricks are used for the aluminum tap and aluminum flow channel.

Refractory Materials for Aluminum Smelting Furnace Lining

In humidifying furnaces, chlorine gas is blown into the molten pool while heating. The siphon lining uses lightweight refractory castable or lightweight clay bricks as the insulation layer, and the working layer uses dense clay bricks or corundum bricks. The insulation layer inside the vacuum ladle is constructed of clay bricks or high-alumina refractory bricks. The insulation layer of the rotary kiln lining is insulated with lightweight clay bricks or perlite bricks, or it can be cast with lightweight refractory castable. The working layer uses clay bricks or grade III high-alumina bricks as the lining.

Induction furnaces are constructed with clay bricks or grade III high-alumina refractory bricks. The furnace bottom uses high-alumina refractory castable as the base layer, followed by high-alumina bricks. For induction furnaces with a capacity of less than 10t, the furnace lining uses high-alumina refractory castable or refractory ramming mix with an aluminum content of 75%, or corundum refractory castable. The furnace inductor coil is vibrated and compacted using corundum refractory castable.

Aluminum insulation furnaces are classified into trough-type induction furnaces, resistance-heated pool-type furnaces, and gas-fired furnaces. Clay bricks are used as the lining. A 10mm asbestos board or refractory fiber felt is used against the furnace shell, followed by a lightweight clay brick insulation layer. The working layer and coils of the furnace are lined with clay-based refractory ramming mix or clay-based refractory castable. For large trough-shaped induction furnaces, the working layer is lined with grade III high-alumina refractory bricks.

For resistance-heated pool-type furnaces and gas-fired furnaces, the insulation layer is made of lightweight clay bricks or lightweight castable. The working layer uses high-alumina bricks with an 80% alumina content, or high-alumina castable. The area above the molten pool uses precast clay bricks or refractory castable blocks, or high-alumina refractory plastic ramming mixes.

The non-working layer of the aluminum molten ladle uses lightweight clay bricks or lightweight castable, while the working layer uses clay bricks or high-alumina refractory bricks. The ladle bottom is lined with high-alumina refractory bricks or corundum refractory castable, and the casting opening is constructed with silicon carbide bricks or corundum bricks.

The thermal equipment used in aluminum refining is the electrolytic cell. The cell walls are made of magnesia bricks, while other parts use clay bricks and high-alumina bricks.