Cement Manufacturers Association (CMA)

33 Refractory Basics and Applications in the Cement Industry KK Shamra & Ketan Goel Invotech Industrial Solutions Private Limited Abstract Refractories play a crucial role in applications where high temperatures and corrosive environments are involved. These specialized materials are essential for insulating and safeguarding industrial furnaces and vessels, offering exceptional resistance against heat, chemical erosion, and physical wear. A malfunction in the refractory system could lead to significant disruptions in production, equipment damages, or even product losses. The selection of appropriate refractory types is vital in ensuring safety, energy efficiency, and product integrity, underscoring the imperative to match the right refractory with each application. Refractory overview Refractories are a type of inorganic, nonmetallic materials that are porous and made up of a mix of thermally stable mineral aggregates, binder phases, and additives. Key ingredients used in refractory production include silicon, aluminum, magnesium, calcium, zirconium oxides, along with various non-oxide materials like carbides, nitrides, borides, silicates, and graphite. These materials are crafted into different forms such as fire-clay bricks, castables, ceramic fibers, and insulating bricks to suit a wide range of applications. The efficacy of refractories isn’t solely based on the cost of the materials used, but also on their performance in specific conditions such as temperature, atmosphere, and the substances they come into contact with. These variables influence the composition of the refractory materials chosen for a particular job. What are refractories used for? Refractories are used by the metallurgy industry in the internal linings of furnaces, kilns, reactors and other vessels for holding and transporting metal and slag. In non-metallurgical industries, the refractories are mostly installed on fired heaters, hydrogen reformers, ammonia primary and secondary reformers, cracking furnaces, incinerators, utility boilers, catalytic cracking units, coke calcinedr, sulfur furnaces, air heaters, ducting, stacks, etc. Majority of these listed equipment operate under high pressure, and operating temperature can vary from very low to very high (approximately 900°F to 2900°F). The refractory materials are therefore needed to withstand temperatures over and above these temperatures. Listed below is the sample melting temperatures of key metallurgical elements where refractory application is critical.