Aluminum melting furnaces in aluminum plants are high-temperature furnace equipment used to melt aluminum and aluminum alloys. They are mainly used for the production, processing, and heating of molten aluminum in the aluminum smelting process. Since aluminum melting furnaces face harsh working conditions such as high temperature, chemical corrosion, and thermal shock during operation, the refractory materials used are required to have good high temperature resistance, corrosion resistance, thermal shock resistance, and wear resistance. Reasonable refractory construction methods and technical requirements are the key to ensuring the long-term operation of aluminum melting furnaces.
1. Construction methods for refractory materials for aluminum melting furnaces in aluminum plants
The construction of refractory materials for aluminum melting furnaces is mainly divided into several steps, including laying refractory bricks, casting construction, and plastic repair. The construction process strictly requires the quality of each link to ensure that the furnace lining can operate stably under long-term high-temperature operation.
1. Construction preparation
Material inspection: Ensure that all refractory materials meet the specification requirements, especially the quality of fire bricks, castings, and plastics must be strictly inspected to ensure that there are no cracks, damage, and other problems.
Tool preparation: including masonry tools (such as bricklaying knives, shovels, hammers), pouring equipment (such as mixers, vibrators), plastic repair tools, etc.
Site cleaning: Clean the inside of the furnace body, remove dust, oil, rust and debris on the surface of the furnace lining, and ensure that the surface is clean so that the material and the substrate are more firmly bonded.
2. Refractory brick masonry
Refractory fire brick masonry is usually used for the lining part of the aluminum melting furnace, and is masonry according to the design drawings.
Binder selection: Select a suitable binder (such as a high-temperature resistant binder) according to the temperature and working conditions of the furnace body, and mix according to the manufacturer's requirements.
Masonry order: Masonry layer by layer according to the design requirements, ensuring that each layer of bricks is laid flat and firm, and the brick joints should be uniform to avoid excessive gaps. The joints between bricks should be as small as possible, and bricks should be trimmed with a bricklaying knife to ensure that the joints are tight.
Compacting and adjustment: During the masonry process, use a light hammer to gently tap the fire bricks to ensure that the bricks are stable and compacted.
3. Refractory castable construction
Refractory castables are suitable for the complex structure, furnace mouth, and non-standard shape parts of the furnace wall of the aluminum melting furnace. During construction, special attention should be paid to the uniformity of the material and the compactness after construction.
Mixing: According to the ratio requirements of the castable, use a mixer to mix evenly. When mixing, ensure that the water ratio is correct to prevent uneven hardening of the castable and affect the later performance.
Pouring: The construction pump used will pour the castable evenly into the designed position. Especially in corners and narrow spaces, careful operation is required to ensure that there are no gaps in the castable.
Vibration: During the pouring process, a vibrator is used to help the castable fully compact, remove bubbles, and avoid the formation of gaps and loose areas.
4. Refractory plastic repair
Refractory plastic is suitable for surface repair of aluminum melting furnaces, especially during the construction of refractory bricks and castables. If there is damage or gaps in the joints, plastic can be used to fill them.
Mixing and blending: According to the instructions of the plastic product, mix water and refractory plastic in the correct proportion and blend to the appropriate plasticity.
Repair construction: Use manual tools to fill the refractory plastic to the position to be repaired. Compact during repair to ensure that the repair area is tightly combined with the surrounding materials.
5. Insulation layer construction
An insulation layer needs to be added to the outside of the aluminum melting furnace, and lightweight refractory insulation materials (such as lightweight silica bricks, refractory fibers, etc.) are used to reduce heat loss.
Apply insulation material: According to design requirements, apply a uniform insulation layer to avoid gaps and ensure the sealing of the insulation layer.
Thickness control: The thickness of the insulation layer should be constructed according to the design requirements to ensure that the insulation effect is ideal.
6. Baking and heating treatment
After the construction is completed, the refractory material of the aluminum melting furnace needs to be baked to eliminate moisture in the material and increase its strength.
Slow heating: The rate of temperature increase should be controlled during the furnace baking process. Usually, the temperature should be increased by 30-50°C per hour to avoid cracks caused by too fast heating.
Staged heating: Gradually increase the temperature to the design temperature and maintain it for a certain period of time to completely evaporate the moisture in the furnace lining and improve the strength of the refractory material.
二. Technical requirements
1. Selection of refractory materials
High temperature performance: Select high-temperature resistant refractory material to ensure that they can maintain stable performance in the high temperature environment of the aluminum melting furnace without softening or melting.
Thermal shock resistance: Since the aluminum melting furnace will experience large temperature fluctuations, the refractory material should have good thermal shock resistance to avoid cracks and bursts caused by drastic temperature changes.
Chemical corrosion resistance: In the internal environment of the aluminum melting furnace, the aluminum liquid may react with the furnace lining and cause corrosion, so the material should have good corrosion resistance.
Wear resistance: The aluminum melting furnace will be subject to mechanical wear during long-term use, especially in the furnace mouth and the circulation area inside the aluminum melting furnace, so the refractory material needs to have high wear resistance.
2. Construction technical requirements
Strict proportion: The proportion of castables, plastics and refractory bricks must strictly follow the standards provided by the manufacturer to avoid material performance not meeting the requirements due to improper proportions.
Construction sequence: According to the requirements of the design drawings, strictly follow the construction steps to avoid uneven overall lining due to incorrect construction sequence.
Construction quality control: After each layer of masonry or pouring construction is completed, it should be carefully checked to ensure that there are no looseness, cracks, gaps and other problems.
3. Furnace baking technical requirements
Temperature rise control: The heating rate should not be too fast, and the temperature should be gradually increased to prevent the material from bursting due to drastic temperature changes.
Temperature monitoring: During the furnace baking process, the temperature in the furnace needs to be monitored in real time to ensure that the temperature rises gradually and evenly to meet the design requirements.
The construction methods and technical requirements of refractory materials for aluminum melting furnaces in aluminum plants are directly related to the service life of the furnace lining and the normal operation of the aluminum melting furnace. Every link in the construction process needs to be strictly controlled to ensure that the quality of the refractory materials and the construction process are in an ideal state. Through the reasonable selection of refractory materials, strict construction technology and appropriate temperature treatment, the service life of the aluminum melting furnace can be effectively extended, the production efficiency can be improved and the production can be ensured.
