technical Characteristics of Refractory Castable Used in Blast Furnaces

Technical Characteristics of Refractory Castable Used in Blast Furnaces

In the iron and steel smelting industry, the blast furnace is one of the core pieces of equipment, and its stable operation plays a crucial role in improving the efficiency of steel production. Refractory castable, as the key material for the lining inside the furnace, directly affects the furnace's service life, production efficiency, and safety. However, there are many problems with the current technology of refractory castable used in blast furnaces during construction. Gaining a deeper understanding of these technical issues helps more blast furnace clients understand the characteristics of refractory castables.

Selection of Raw Materials and Production Technology for Refractory Castables Used in Blast Furnaces

High-quality raw materials are the foundation for producing high-performance refractory castables. For example, high-purity refractory raw materials such as corundum and mullite have good high-temperature resistance and chemical stability. Advanced ore selection and purification technologies can improve the purity and quality of the raw materials. For instance, using flotation and magnetic separation methods to remove impurities from the raw materials can significantly enhance the performance of refractory castables. Moreover, reasonable particle size grading of the raw materials is also one of the key technologies. By optimizing particle size distribution, the porosity of the castable can be reduced, thus improving its density and strength.

Application of Premium Additives in Refractory Castables:

Additives play a crucial role in refractory castables. Water reducers can decrease the water content in the castable, improving its fluidity and construction performance while reducing porosity and increasing strength. Setting retardants and accelerators can adjust the setting time of the castable to meet the needs of different construction conditions. In addition, some special additives, such as antioxidants and anti-spalling agents, can improve the oxidation resistance and thermal shock resistance of the castable, thereby extending its service life.

Construction and Curing Methods for Refractory Castables Used in Blast Furnaces:

During construction, it is necessary to strictly control parameters such as the mixing time of the castable, water content, and construction temperature. Uniform mixing ensures the consistency of the castable's performance, while the appropriate amount of water and construction temperature are conducive to the shaping and hardening of the castable. The curing process is also not to be overlooked; a reasonable curing system can promote the hydration reaction of the castable, improving its strength and stability. For example, when constructing in high-temperature environments, appropriate cooling measures need to be taken to prevent the castable from drying too quickly and cracking. Therefore, correct construction and curing methods are key to ensuring that the refractory castable's performance is fully utilized.

The Main Problems Faced by Refractory Castables Used in Blast Furnaces Include:

Deformation or Spalling After High-Temperature Exposure:

The interior of the blast furnace is extremely hot, and the refractory castable needs to withstand prolonged high temperatures. However, some refractory castables currently tend to soften, deform, and spall under high temperatures, leading to lining damage, affecting the normal operation of the blast furnace. This not only increases maintenance costs and downtime but may also cause safety accidents. For instance, in some large blast furnaces, due to the inadequate high-temperature performance of refractory castables, the furnace lining needs to be repaired or replaced at regular intervals, severely affecting production efficiency.

Poor Thermal Shock Resistance:

During operation, the blast furnace undergoes frequent temperature changes, such as during start-up, shutdown, and tapping processes. Such abrupt temperature changes generate thermal stress in the refractory castable, leading to cracking and spalling. Poor thermal shock resistance is one of the main pain points currently faced by refractory castables. Some castables show significant cracking and spalling after several thermal cycles, greatly shortening their service life.

Severe Chemical Erosion:

The slags, iron, and gas inside the blast furnace are highly chemically corrosive. During prolonged exposure to these media, refractory castables are prone to chemical erosion, leading to a decline in their performance. For example, alkaline oxides in the slag can react chemically with the acidic components in the refractory castable, destroying its structure. Moreover, elements such as sulfur and phosphorus in the gas can also erode the refractory castable.

In response to these main issues, Gongyi Yuying Refractory  Co., Ltd., has developed new raw materials to produce high-quality refractory castables to address the problems faced by refractory castables used in blast furnaces. For example, developing refractory raw materials with higher melting points and better chemical stability, as well as new types of additives, to enhance the high-temperature performance, thermal shock resistance, and chemical erosion resistance of the castables. Additionally, researching the application of nanotechnology in refractory castables, utilizing the filling and reinforcing effects of nanoparticles to improve the microstructure of the castables and enhance their performance.

Optimizing Construction Techniques:

Further optimizing construction techniques can improve the construction quality and performance of refractory castables. Using advanced construction equipment and technologies, such as mechanized construction and automated controls, can enhance construction efficiency and quality stability. At the same time, strengthening quality control during construction and strictly following construction specifications ensures the quality of the castable installation.

Enhancing Monitoring and Maintenance:

Establishing a comprehensive monitoring system for the blast furnace lining to monitor the usage status of refractory castables in real-time. By monitoring parameters such as temperature, stress, and wear, abnormal conditions of the lining can be detected promptly, and corresponding maintenance measures can be taken. Regularly inspecting and maintaining the blast furnace lining, promptly repairing damaged areas, can extend the service life of refractory castables.

Refractory castable technology plays a significant role in the iron and steel smelting industry, but it currently faces challenges such as insufficient high-temperature performance, poor thermal shock resistance, and severe chemical erosion. Gongyi Yuying Refractory Co., Ltd., through the development of new materials, optimizing construction techniques, and enhancing monitoring and maintenance, can effectively address these pain points, improving the performance and service life of refractory castables, providing robust support for the stable operation of blast furnaces. It is believed that refractory castable technology for blast furnaces will continue to develop and improve, making greater contributions to the sustainable development of the steel industry.