# What is firebricks which is used in Down's Cell? What is its role?

Apr 20, 2018

Firebrick is a ceramic material that is used for lining furnaces and kilns.

#### Explanation:

Firebrick is stable at high temperatures and has low thermal conductivity.

A Downs cell operates at 600 °C. It consists of a steel shell lined with firebrick.

The firebrick serves three functions:

• It protects the steel shell from the corrosive effects of the molten ${\text{NaCl"//"CaCl}}_{2}$ mixture

• It acts as a thermal insulator, thus keeping the heat inside the cell and promoting energy efficiency

• It acts as a self-sealing lining. The firebrick is thick enough that if a crack develops, the electrolyte freezes in the crack before it reaches the steel shell.