How are firebricks formed during dry pressing and stiff-mud processing?

Firebricks are refractory materials designed to withstand high temperatures, and they are shaped using methods similar to those used for standard building bricks.1

Stiff-Mud Processing

In the stiff-mud process, raw materials are mixed with enough water to create a plastic consistency. This mixture is then forced through a die using an extrusion machine, which produces a continuous column of material. This column is then cut into individual brick units using wires.23

Dry-Press Processing

The dry-press process is utilized for materials with very low plasticity. In this method, a minimal amount of water is added to the raw material. The mixture is placed into steel molds, and high pressure—reaching up to 1,500 pounds per square inch—is applied to form the bricks. This pressing technique, which can be performed using single-action or dual-action die presses, helps eliminate porosity and ensures the material achieves the desired shape.24