Refractories are used by the metallurgical industry in the internal linings of the furnaces, kilns, ovens, furnaces, reactors, and other vessels for holding and transporting of liquid metal and liquid slag. In non-metallurgical industries, the refractories are mostly installed on fired heaters, hydrogen reformers, ammonia primary and secondary reformers, cracking furnaces, utility boilers, catalytic cracking units, coke calciner, sulphur furnaces, air heaters, ducting, stacks, and incinerators etc. Majority of these listed equipment operate under high pressure, and operating temperature can vary from very low to very high (around 500 deg C to 1,650 deg C). The refractory materials are hence required to withstand temperatures above these temperatures.
Al2O3 and MgO-based refractories are mostly consumed in the steel industry. Research on introducing nano-carbon in oxide–carbon refractory is meant for obtaining a high grade low-carbon steel without affecting the refractory properties.
Good quality raw materials are one of the primary requirements to produce refractories with improved properties. In India, as good quality refractory raw materials are not available, focus is on to upgrade the available materials through proper processing. Judicious recycling of used refractory is another option to partially substitute for virgin raw materials.
