Extending the service life of castables is the key to ensuring the long-term and stable operation of equipment such as kilns. The following are some effective measures and methods:
1. Reasonable material selection and design
Select materials according to the use environment:
Different kiln working conditions (such as temperature, chemical erosion, physical impact, etc.) require refractory materials to have different characteristics.
In highly corrosive environments, select refractory materials with high corrosion resistance.
In areas subject to large mechanical impact, select refractory materials with high toughness.
Choose raw materials with low expansion coefficients:
The thermal expansion coefficients of aggregates and matrix materials should match the working conditions of the kiln to reduce thermal stress caused by temperature changes.
2. Optimize construction quality
Keep the construction environment clean:
Before construction, ensure that the working environment, construction tools and equipment are kept clean to prevent contamination of refractory materials.
Strictly follow the construction instructions:
Follow the construction instructions of refractory castables and do not construct at will.
Clean up the construction site according to the design size requirements and prepare the required machinery and materials.
Pay attention to the construction method:
Uniform mixing, proper vibration, accurate pouring and proper curing are the key steps to ensure the density and uniformity of the castable.
Use special mixing equipment, control the mixing time, and avoid excessive wear or unevenness of the material.
Use a vibrating rod for vibration to remove bubbles and improve the density of the castable.
Reduce construction joints:
During the construction process, minimize the generation of construction joints.
If necessary, the cross section flows into a stepped shape to reduce stress concentration.
3. Strengthen curing and baking
Reasonable curing:
Curing can give the binder in the castable a solidification and hardening time to obtain sufficient initial strength.
Curing methods include natural curing and steam curing. The specific choice depends on the type of binder of the castable and the construction environment.
Proper baking:
Baking is to remove excess moisture in the castable, promote the sintering process at high temperature, and further improve the physical properties of the castable.
The baking process should be carried out strictly according to the baking curve to avoid heating too fast or too slow.
4. Take protective measures
Apply anti-expansion asphalt:
Apply anti-expansion asphalt to metal parts that are in contact with or wrapped by the castable to facilitate the free expansion of the metal without squeezing the castable.
Surface protection:
Applying waterproof coating can prevent moisture penetration.
If necessary, other surface protection measures can also be taken to extend the service life of the castable.
5. Regular inspection and maintenance
Inspection content:
Regularly check the surface condition of the castable, the fixing condition of the anchors, the sealing of the joints, etc.
Maintenance measures:
When problems are found, timely repair measures should be taken, such as repairing cracks, replacing damaged anchors, resealing joints, etc.
6. Control the operating conditions of the furnace
Reduce the number of starts and stops:
The number of starts and stops of the furnace is reduced to a limit to reduce the thermal shock to the castable.
Control temperature changes:
The temperature rises slowly when starting and stopping the furnace to avoid drastic temperature changes causing thermal fatigue of the castable.
Control the chemical environment:
The chemical environment in the furnace should also be controlled to avoid damage to the refractory materials caused by chemical erosion.
To extend the service life of castables, we need to start from material selection and design, construction quality, curing and baking, protective measures, regular inspection and maintenance, and control of furnace operating conditions. By taking these measures and methods, we can ensure the long-term stable operation of kilns and other equipment.
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