Refractories play a vital role in high temperature industry, and their service life is directly related to the continuity, safety and economic benefits of industrial production. The following are some effective methods to extend the service life of refractory materials:
Reasonable selection of refractory materials
According to the use of environmental selection of materials: different kiln working conditions are different, such as temperature, chemical aggressiveness, physical impact, etc., which requires refractory materials have different characteristics. For example, in a highly corrosive environment, need to choose high corrosion resistance refractory materials; in the area of large mechanical impact, should be selected with high toughness refractory materials.
Match the coefficient of thermal expansion: the coefficient of thermal expansion of the refractory material should be matched with the working conditions of the kiln, in order to reduce the thermal stress caused by temperature changes. If the coefficient of thermal expansion is not matched, the refractory material is prone to cracks, spalling and other damages when the temperature fluctuates.
Optimize the construction process
Ensure material homogeneity: Proper construction methods include uniform mixing, proper vibration, accurate pouring and proper maintenance. When mixing the refractory castables, special mixing equipment should be used and the mixing time should be controlled to avoid excessive wear and tear or unevenness of the materials.
Ensure the quality of construction: During the construction process, it should be carried out in strict accordance with the operating procedures to ensure the denseness and uniformity of the castables. For example, during the pouring process, use vibrating rod to vibrate, remove air bubbles and improve the denseness of the castables.
Strictly control the maintenance and baking process
Reasonable maintenance: Maintenance can avoid the early strength loss of refractory materials. There are usually two kinds of conditioning methods: natural conditioning and steam conditioning. The specific choice depends on the type of bonding agent of the castables and the construction environment.
Proper baking: The baking process should be carried out in strict accordance with the baking curve, avoiding too fast or too slow heating, and ensuring that the moisture in the castables can be evenly discharged. If the baking is not done properly, the moisture will form vapor pressure inside the material, which may lead to structural damage.
Well-designed anchorage systems
Provide mechanical fixing force: The anchors should not only provide sufficient mechanical fixing force, but also take into account the effect of thermal expansion to avoid damage caused by thermal stress. Their design should be based on the specific structure and working conditions of the kiln, selecting the appropriate material and arrangement.
Ensure the quality of welding: During construction, the welding quality of the anchors should be ensured to avoid failure of the anchors due to welding defects.
Use high-performance admixtures
Improve construction performance: Admixtures can effectively improve the construction performance and final performance of refractory castables. For example, plasticizers can improve the fluidity of the castables, and coagulants can accelerate the curing speed.
Enhance the overall performance: When selecting admixtures, it is necessary to determine the appropriate varieties and additive amount according to the specific type of castables and use conditions, and consider their compatibility and long-term stability.
Take surface protection measures
Coating protective materials: evenly coat the surface of refractory castables with protective materials, such as waterproof coating to prevent moisture penetration, and anti-expansion asphalt to reduce the thermal impact of metal parts on the castables.
Regular inspection and maintenance: Regularly check the integrity of the protective layer and repair the damaged part in time to ensure the protective effect.
Control the amount of water and construction humidity
Control the amount of water: The amount of water directly affects the hardening process and the final strength of the refractory castables. Too much water will reduce the strength of the castables, too little will affect the construction performance, according to the type of castables and construction environment, strict control and timely adjustment.
Maintain suitable humidity: the humidity of the construction environment also affects the hardening and strength development of the castables, and suitable humidity conditions should be maintained to avoid the adverse effects of humidity on the performance of the material.
Regular inspection and maintenance
Timely detection of problems: Regularly check the surface condition of the refractory material, the fixing of anchors, and the sealing of joints. By discovering small damages and repairing them in time, problems can be prevented from expanding.
Taking repair measures: Once problems are found, repair measures should be taken in time, such as repairing cracks, replacing damaged anchors, and resealing joints.
Reasonable operation and control of furnace working conditions
Stabilize temperature change: avoid frequent starting and stopping of the kiln, control the speed of heating and cooling to prevent thermal stress due to rapid temperature change, causing damage to the refractory material.
Control the chemical environment: control the chemical environment in the kiln to avoid damage to the refractory material due to chemical erosion. For example, strictly control the furnace atmosphere, slag composition, etc., to reduce the erosion of refractory materials.
Introduction of fiber reinforcing materials
Improve toughness and crack resistance: Adding stainless steel fibers or inorganic fibers to refractory castables can significantly improve their toughness and crack resistance. These fibrous materials disperse stresses and reduce damage caused by thermal or mechanical shock.
Pay attention to fiber characteristics: when choosing fiber materials, consider their compatibility with refractory castables, as well as factors such as fiber diameter, length and addition amount to ensure that the fibers are uniformly dispersed in the castables and are fully bonded with the castables.
Extending the service life of refractory is a systematic project, which needs to be considered and optimized comprehensively in many aspects, such as material selection, construction process, maintenance and baking, anchorage design, use of admixtures, surface protection, control of water addition, regular maintenance, and kiln operation, etc., so as to provide a more stable and economic guarantee for industrial production.
