How are refractory bricks made?

Refractory bricks, also known as refractory fire bricks, are generally made by heating fireclay until it becomes vitrified in part. Dense refractory brick is famous for its ability to withstand high temperature, which is a useful property that can be applied in a variety of fields. Therefore, some people may wonder why refractory fire bricks are able to possess the valuable property of thermal resistant. How are refractory bricks made and what are the ingredients used in the making process?

-        Material used in making dense refractory bricks. 

-        Manufacturing process of dense refractory bricks.

Material used in making dense refractory bricks

The material used in dense refractory brick may vary depending on its own composition. To be specific, using composition as the classification criterion, there are many types, including silica-alumna refractory fire bricks, alkaline series refractory fire bricks, carbon- containing refractory fire bricks, zirconium-containing refractory fire bricks and thermal insulation refractory fire bricks. These names indicate the ingredients utilized in the making process. But generally speaking, silica and alumina are the two most widely used ingredients. Moreover, due to Alumina’s property of highly thermal resistant, some refractory fire bricks contain alumina to a very high degree, thus these dense refractory bricks are also called as high alumina refractory bricks.

Manufacturing process of dense refractory bricks

Step 1.  We need to make the molding box which regulates the size of the refractory brick that you intend to manufacture. The molds are generally made from studs and two pieces of plywood that are placed at the bottom of the box. Remember to caulk or seal the seams.

Step 2. Mix the cement. Use another container and pour some masonry cement into it. Meanwhile, we also have to add some other ingredients, including perlite, fireclay and sand. Then we need to use a stirring tool such as shovel to mix it until it is thoroughly blended.

Step 3. Add water into the dry mixture to make sure it is at the right consistency. In order to expose the mixture to the water to the greatest extent, we can create a hole in the center of the mixture and pour some water into it. Then we slowly fold the mixture into the water until it becomes crumbly.

Step 4. Pour the ready-made refractory bricks cement into the molding box and pack it to the largest extent. We also need to settle the mixture and remove the air bubbles inside. To achieve this, we can use a hammer to make the second piece of plywood at the bottom of the box vibrate.

Step 5. Cover the molding box with a piece of plastic sheeting and tape it to the mold with duct tape. After keeping the refractory mixture moist for several days, we then remove the plastic and let the cement stand for the next few days.

Step 6. After all the steps above, the dense refractory brick is made. All we have to do now is to release the brick from the molding box.