The core functions of refractory additives are twofold: one is to improve production or construction processes, and the other is to enhance the performance of refractory materials. Simply put in refractory mixer, it means making materials easier to make, more usable, and more durable.
There are many types of additives, and different additives solve different problems. They can be divided into the following directions:
Improve production and construction processes
These types of additives mainly make refractory materials more convenient during molding and construction, such as:
Water reducing agent: significantly reduces the amount of water used in mixing by refractory mixer and increases the density of materials without affecting fluidity.
• Accelerator/retarder: Adjust the setting and hardening speed of amorphous refractory materials to adapt to different construction times and conditions.
Plasticizers: Improve the plasticity of materials and facilitate molding.
Dispersant: allows a small amount of components in the formula to be distributed more evenly in the material, avoiding local performance differences.
Enhance high-temperature performance
These types of additives directly determine the lifespan and reliability of refractory materials at high temperatures, such as:
Antioxidants: They protect graphite from oxidation in carbon containing refractory materials and inhibit the addition of carbon to molten steel, which is important for smelting clean steel.
Mineralizer: Promotes mineral formation through chemical reactions, optimizing the microstructure at high temperatures.
• Sintering aid: Reduce sintering temperature, promote material densification, and improve strength.
• Expansion agent: Reduce or prevent material shrinkage at high temperatures and maintain dimensional stability.
Enhance structural strength and durability
These types of additives make the material itself stronger and more resistant to corrosion:
• Bonding agents: such as phosphates, phenolic resins, asphalt, etc., to ensure that the green body has sufficient strength during production and construction processes.
Stabilizers: Maintain the stability of material structure, for example, modified asphalt can improve the material's resistance to corrosive substances such as heat, acid, and alkali, and extend its service life.
Examples of common additives
Different material systems will be combined with different additives, for example, aluminum magnesium refractory materials commonly use sodium tripolyphosphate and sodium hexametaphosphate as water reducing agents, and citric acid as a retarder; Chromium oxide green is commonly used to improve the high-temperature performance and structural strength of refractory bricks and castables.
Finally we can get conclusion the mixing equipment for those refractory additives is so critical by a professional refractory mixer.
