Ceramics-Refractories

 **REFRACTORIES**
 * Refractory** - a material having the ability to retain its physical shape and chemical identity when subjected to high temperatures. //(2)//

Refractories have been used by humankind since earliest recorded history. When humans first began to smelt metals and shape primitive knives, hunting weapons, and ornamental rings and jewelery, crude refractory materials were developed to facilitate the ** pyroprocessing ** of the ores. As refractory practice developed, materials evolved which were ever more durable, lasting longer and longer before replacement was necessary. //(1)//
 * History**

Refractory products are nonmetallic materials that withstand severe high temperature service conditions. They must resist chemical attack; withstand molten metal and ** slag ** erosion; endure thermal shock, physical impact, ** catalytic ** heat; and other rigorous conditions. Generally, refractory products are needed in processes where temperatures exceed 700°F. Some applications call for service temperatures of 3500°F or higher. //(1)//
 * General Information**

Refractory products are, in many cases, the only materials that can contain or control high temperature processes, making them critical to the United States industrial base. Refractories line the furnaces and smelters that refine steel, copper, aluminum, and other metals. They are used in cement kilns and glass furnaces, as well as in petroleum cracking and processing. Power generators, boilers, and other combustion equipment all use refractories. //(1)//

**References** //(1)// __Refractory Ceramics Divisions__. 2007. The American Ceramic Society. 30 Apr. 2009 <[|http://www.ceramics.org/community/divisions/refractory...]>. //(2)// __Refractory Defintion__. 2009. Dictionary.com. 30 Apr. 2009 <[]>.