Why are some refractory raw materials fired in rotary kilns before brickmaking?

Some refractory raw materials, such as magnesite and dolomite, are fired in rotary kilns before brickmaking to achieve sintering and densification.1

This process, often referred to as dead-burning, involves calcining the material at high temperatures for an extended period to drive off components like carbon dioxide. By inducing these structural changes prior to fabrication, the material becomes dense and stable. Once this pre-treated material is crushed and sized, it can be formed into specific refractory shapes and subsequently refired to create the final product. This preparation is essential for ensuring the material possesses the necessary physical properties to withstand high-temperature environments.213