With the rapid development of smelting technology and the steel industry, metallurgical refractories have also undergone a major technological revolution, moving away from a heavy reliance on natural raw materials and raw products and gradually moving towards refined products based on synthetic materials. Monolithic refractories offer significant advantages over shaped refractories due to their ease of mechanized and automated production and their ability to extend their service life through repair. As a result, they have become a key component of metallurgical production.
1.What is monolithic refractory?
Monolithic refractories are a new type of refractory material that is amorphous in shape, unfired, and can be used directly, made by mixing aggregate, fine powder, binder, and admixtures in a certain proportion. Compared with shaped refractory materials, monolithic refractories do not require a complicated firing process. The raw materials required for their production are easily available and inexpensive, the production process is simple, and they are very plastic. The refractoriness and chemical stability of monolithic refractories can reach the level of similar refractory bricks, making them easy to prefabricate into blocks. In smelting production, it is easy to produce products of various complex shapes, and it is conducive to the mechanization of furnace construction. In addition, unshaped refractory materials are also relatively convenient to use and can be used directly or after mixing.
2.Application advantages of monolithic refractories in the metallurgical industry
Excellent high-temperature resistance:
Monolithic refractories are typically made from high-temperature-resistant mineral materials, such as bauxite and silicates. This allows them to withstand the high temperatures encountered in metallurgical production, particularly those subject to significant temperature fluctuations within the furnace. Their excellent refractory properties ensure stable operation of metallurgical furnaces.
Excellent shock and thermal shock resistance:
Metallurgical processes involve large temperature fluctuations and frequent furnace operations. Compared to shaped refractories, monolithic refractories can effectively adapt to rapid temperature fluctuations and offer superior shock and thermal shock resistance, reducing material damage and equipment downtime.
Efficient plasticity and workability:
Monolithic refractories, typically in powder or granular form, exhibit excellent plasticity, facilitating on-site installation tailored to the furnace type and application requirements. They can more precisely conform to the furnace shape, avoiding gaps and uneven installation associated with shaped refractory materials, thereby improving thermal efficiency and safety.
Excellent chemical resistance:
Smelting processes in the metallurgical industry often involve intense chemical reactions. The high temperatures and corrosive substances within the furnace can severely erode refractory materials. Unshaped refractory materials can be optimized for different metallurgical media during design, offering enhanced chemical resistance and extending service life.
3.Specific applications of Monolithic refractories in the metallurgical industry
Application of monolithic refractories in blast furnaces:
As a crucial piece of equipment in the metallurgical industry, traditional blast furnaces utilize steel plates for their shells, lined with refractory bricks. High-alumina cement and high-alumina phosphate refractory castables are typically hoisted and laid in precast blocks. Modern blast furnaces primarily utilize resin-bonded aluminum-carbon unfired bricks. Large blast furnaces utilize SiC castables for their water-cooled walls, while the furnace floor cushion and surrounding brick joints are filled with silicon nitride. The use of castable refractory materials for furnace walls has become a common practice in the industry, achieving excellent results.
Application of monolithic refractories in ladles:
Due to rising tapping temperatures and extended steel retention times in ladles, monolithic refractories are gradually replacing the previously used monolithic refractories in ladle refractories. Ladles are used to hold molten steel. During the smelting process, the ladle lining is subject to intense corrosion from the molten steel and slag. Monolithic refractories offer excellent corrosion resistance, forming a stable refractory barrier when in contact with the molten steel and slag, preventing direct corrosion of the ladle. Furthermore, the plasticity of these materials allows them to form a uniform, seamless protective layer on the ladle lining.
Refractory linings in converters and electric arc furnaces:
During the high-temperature smelting processes of converters and electric arc furnaces, the furnaces are exposed to extreme conditions such as chemical corrosion, thermal shock, and wear. Monolithic refractories, particularly those made from high-quality bauxite, magnesia, or silica slurries, offer excellent corrosion and thermal shock resistance. They effectively protect the furnace from erosion by molten metal, oxides, and furnace gases, thereby extending the service life of the lining and reducing the frequency of maintenance shutdowns.