Firing or Burning Bricks
Firing temperatures are often quite critical and will vary considerably between different clay types but are generally in the range of 900-1300 degrees
centigrade. The length of firing is another key factor that has an impact on the properties of the finished brick.
The firing process takes place in three stages. First, preheating ensures total dryness of the bricks and raises the brick temperature. Next, a fuel such as natural gas, oil or coal is used to raise and maintain the temperature to the required firing level over a few hours. Finally, cold air is drawn into the kiln to cool the bricks slowly, ready for sorting and packing.
Bricks undergo a physical change during the firing process. Clay particles and impurities are fused together to produce a hard, durable and weather-resistant finished product. This process is known as ‘vitrification’ and is accompanied by further shrinkage and a colour change.