Introduction to 7 types of aluminum smelting furnaces and refractory materials used

Aluminum smelting furnaces mainly include reverberatory furnaces, rotary drum furnaces and induction furnaces, etc. The operating temperature is generally 700-1000°C. The damage to the lining of this type of furnace is mainly caused by the penetration and erosion of aluminum liquid. The lining is generally built with clay bricks, high-alumina refractory bricks and corundum-mullite bricks. High-aluminum refractory castables and refractory refractory materials can also be used. Made of plastic, the stove has a long life due to good usage conditions.

1 Refractory materials for reverberatory furnaces

The furnace is divided into two types: fixed type and tilting type. Generally, gas or heavy oil is used as fuel. Aluminum is usually smelted with a fixed reverberatory furnace. The non-working layer is built with refractory fiber felt and clay insulating refractory bricks. The working layer above the molten pool is built with clay bricks. Prefabricated blocks of high-aluminum refractory castables can also be used. It is hoisted or poured on site or pounded with high-aluminum refractory plastic. The working layer of the molten pool has different materials according to different usage requirements. Generally, high-aluminum refractory bricks with an Al2O3 content of more than 75% are used. , high-aluminum refractory castables with an Al2O3 content of 80% can also be poured into the overall working layer. When melting high-purity metallic aluminum, the working layer of the molten pool should be made of high-purity mullite bricks, zircon bricks or corundum. Brick masonry. In order to resist the penetration and erosion of liquid aluminum, the aluminum discharge port, aluminum flow trough and its lining are generally built with large silicon carbide bricks.

The refractory materials used in the moisturizing furnace and its flux and alloy processing chamber are basically the same as those in the reverberatory furnace. When aluminum ingots or scrap aluminum are used as raw materials, they can be directly loaded into the furnace from the charging port for smelting. When electrolytic aluminum liquid is used as raw material. The aluminum liquid is first sucked out from the bottom of the aluminum electrolytic tank with a siphon or vacuum bag, and then transported to the reverberatory furnace. Pour in from the charging port. After charging, blow chlorine into the molten pool while heating for dehydrogenation. The siphon is usually lined with refractory fiber-reinforced lightweight refractory castable as the insulation layer. Clay insulation can also be used. For refractory brick masonry, the working layer is generally constructed with dense clay bricks or corundum bricks. The thermal insulation layer inside the vacuum bag is the same as that of the siphon. The working layer is built with high-quality clay bricks or high-alumina refractory bricks. Under normal operation, the service life of reverberatory furnaces and holding furnaces is generally 2-5 years.

2 Refractory materials for rotary drum furnaces

The non-working layer of the furnace is constructed with clay insulating refractory bricks or floating bead bricks. It can also be poured with lightweight refractory castables with a bulk density of 1.0g/cm3 or made into prefabricated blocks: the working layer is constructed with dense clay bricks or It is built with high-alumina refractory bricks containing more than 55% aluminum, and the rotary drum furnace age is generally 300-500 heats. When adding salt flux to smelt aluminum blocks. Due to the intensification of chemical corrosion, its furnace age has been reduced.

3 Refractory materials for induction furnaces

The furnace lining is generally built with clay bricks or third-grade high-alumina refractory bricks. Sometimes the base layer of the furnace bottom is poured with high-aluminum refractory castables, and then high-alumina refractory bricks are laid. When the capacity of the induction furnace is less than 10t, the lining can be made of high-aluminum refractory castables or refractory ramming materials with an Al2O3 content of about 75%, or corundum refractory castables or dry vibrating materials. The lining around the furnace inductor coil is generally poured with corundum refractory castables or vibrated densely with dry vibrating materials. During use, vulnerable parts such as the lining body around the coil should be repaired 1-5 times.

4 Refractory materials for holding furnaces

Aluminum holding furnaces are divided into trough induction furnaces, resistance heating pool furnaces and gas chamber furnaces. Due to the low operating temperature of this type of equipment, clay bricks and other materials are generally used as linings, and they also have a relatively long service life.

5 Refractory materials for trough induction furnaces

The lining structure of the furnace is to first lay 10mm asbestos board or refractory fiber felt against the furnace shell, and then lay clay insulating refractory bricks or floating bead bricks as the insulation layer; the working layer of the furnace and the lining around the coil are generally made of clay. It is made of high-quality refractory ramming material, or can be poured on-site with clay refractory castables. The working layer of a large trough-shaped induction furnace can also be built with high-aluminum refractory bricks with an Al2O3 content greater than 55%.

6 Refractory materials for resistance heating pool furnaces

The non-working layer of the furnace is built with clay insulating refractory bricks, floating bead bricks or insulation boards. Lightweight refractory castables with a volume density of 0.8g/cm3 can also be poured as a whole; the working layer of the molten pool is constructed with high-aluminum refractory bricks with an Al2O3 content of approximately 80%, or high-aluminum refractory bricks with a volume density of 2.4g/cm3 can be used. Refractory castable pouring. The working layer above the molten pool is generally built with clay bricks or refractory castable prefabricated blocks, or it can also be made of high-aluminum refractory plastic.

7 Refractory materials for gas hearth furnaces

The furnace consists of a furnace bottom, furnace walls and a furnace top. It can be used alone. In order to save energy and facilitate management, it can also be used in conjunction with the reverberatory furnace for aluminum smelting. The furnace lining material is clay brick and high alumina refractory brick.

8 Refractory materials for aluminum water tanks

Aluminum water tank is a thermal equipment used to contain, transport and cast aluminum liquid. The non-working layer of the tank wall is built with clay insulating refractory bricks, and can also be poured with lightweight refractory castables with a bulk density of 1.5g/cm3. The working layer is built with clay bricks or high-aluminum refractory bricks, or it can be poured with alumina hollow ball refractory castables; the bottom of the tank is built with high-aluminum refractory bricks, or it is poured with corundum refractory castables, and its surface is coated with refractory castables. Spread material as a protective layer. Due to the erosion and erosion of molten aluminum, the casting port is generally built with silicon carbide bricks, corundum bricks or fused quartz bricks. In China, a stopper rod device is commonly used to control the pouring of liquid aluminum from aluminum water tanks.

9 Refractory materials for aluminum refining

The thermal equipment used in refining is an electrolyzer. The tank wall is built with magnesia bricks, and the remaining parts are made of clay bricks and high-alumina refractory bricks. During electrolysis, the tank temperature is generally 720-800°C. The tank lining has good usage conditions and low operating temperature, so it has a long service life.