Requirements for the use of aluminum melting furnace linings
After melting, aluminum metal has very close properties to water at 20°C and has extremely strong permeability. It can easily wet refractory materials and react chemically with them, causing volume changes in the refractory materials, causing cracks and gradually destroying the refractory materials. It is required to increase the density of refractory materials and reduce the porosity of refractory materials, which can effectively prevent the penetration of liquid aluminum and its alloys. Improve the corrosion resistance of refractory materials to aluminum water. The higher the aluminum content and the higher the purity, the lower the probability of reacting with aluminum water, and the better the corrosion resistance. At the same time, additives such as barium salts, chromium salts, etc. can also be added to react with aluminum water to form a protective layer to increase the corrosion resistance of refractory materials. The wear resistance of refractory materials is mainly to improve their strength, which can effectively increase the wear resistance and mechanical impact resistance of refractory materials.
High permeability aluminum bricks are mainly used in aluminum melting furnaces in the aluminum industry. Insulated furnace lining. High-permeability aluminum bricks have high strength, low apparent porosity, and excellent cryolite corrosion resistance. Their function is to prevent Na.NaF and cryolite melts from further penetrating into the insulation layer, preventing corrosion of the insulation layer, and long-lasting insulation capabilities. They are used in domestic aluminum furnaces During use, it can meet the needs of long service life of aluminum electrolytic cells.
Aluminum melting furnace shell steel structure and furnace lining.
The steel structure of the aluminum melting furnace is generally welded by 10-12mm thick carbon steel plates and section steel, with sufficient stiffness and good air tightness. Aluminum melting furnaces equipped with electromagnetic stirring devices at the bottom of the furnace should use non-magnetic stainless steel thick steel plates.
The lining materials are different in different parts of the furnace. The molten pool is made of high-quality high-alumina bricks (LZ-75), impermeable aluminum castables and insulation bricks; the side walls above the liquid level of 250-300mm are composed of high-quality clay bricks, refractory concrete, insulation bricks and calcium silicate boards; The furnace top is a suspended flat furnace top, which is suspended on the furnace top steel using heat-resistant steel metal anchors every 300mm or so. For tilted aluminum melting furnaces, the lining structure of the side wall on the molten pool can be made of amorphous refractory material and connected to the side wall steel structure through heat-resistant steel anchors to adapt to the working conditions when the furnace is tilted. The large furnace doors of aluminum melting furnaces are usually welded from ordinary carbon steel plates and section steel, and are lined with refractory castables and insulating lightweight castables. The furnace door frame and the seal around the furnace door consist of small pieces and heat-resistant castings with machined surfaces respectively. The furnace door and the furnace door frame are softly sealed by an aluminum silicate fiber braided rope embedded in a heat-resistant casting groove around the furnace door.
Using high bauxite as the main raw material, adding additives, and firing high alumina bricks, which are resistant to aluminum penetration.
