High-temperature resistant concrete and refractory castables process flow

Heat-resistant concrete, also known as refractory concrete, is a special type of concrete that can withstand high temperatures (above 200°C) for extended periods while maintaining the required physical properties. It is commonly used in thermal equipment and structures subjected to high temperatures, such as the foundation engineering of blast furnaces, converters, and coke ovens in the metallurgical industry, as well as the inner linings of chimneys.

◆  Its refractoriness is similar to that of refractory bricks made from the same material. However, since refractory concrete (castable) is not sintered, it experiences significant shrinkage during initial heating, resulting in a slightly lower load softening point compared to refractory bricks. Despite this, its overall performance is superior to that of refractory bricks.

◆  Refractory concrete outperforms low-temperature binder materials, exhibiting high compressive strength at room temperature. Additionally, due to the integrity of the masonry, the furnace's air tightness is improved, reducing the likelihood of deformation. The external steel shell of the furnace can be eliminated, and the furnace's resistance to mechanical vibration and impact is better than that of brick masonry. For example, when used in the upper part of the side walls of soaking pits, where mechanical wear and collision are severe, its lifespan is several times longer than that of brick masonry.

◆  It has excellent thermal stability. Most or all of the aggregate is clinker, and its expansion offsets the shrinkage of the binder, resulting in relatively lower thermal expansion of the masonry compared to bricks and reduced thermal stress. Moreover, the structure contains various network, needle-like, and chain-like crystalline phases, enhancing its resistance to low-temperature stress. For instance, when used for casting the furnace mouth and lid of soaking pits, the lifespan can be extended to one and a half years.

◆  The production process is simple, eliminating the complex brick-making procedures. It can be manufactured into various prefabricated blocks and allows for mechanized construction, significantly accelerating furnace construction speed—improving efficiency by more than ten times compared to brick laying. Additionally, waste bricks and other materials can be repurposed as aggregates, turning waste into valuable resources.