Refractory bricks are classified using various methods:

1. Chemical Composition: Refractory bricks can be categorized based on their chemical composition into acidic refractory bricks, alkaline refractory bricks, and neutral refractory bricks.

2. Refractoriness: Refractory bricks can be classified by their refractoriness temperature:

   • Ordinary refractory bricks: 1580°C to 1770°C
   • High-grade refractory bricks: 1770°C to 2000°C
   • Special-grade refractory bricks: Above 2000°C
   • Super refractory bricks: Above 3000°C

3. Manufacturing Process: Refractory bricks are also classified by their manufacturing process:

   • Fired refractory bricks
   • Fused refractory bricks
   • Unfired refractory bricks
   • 

4. Application: Based on their application, refractory bricks can be classified for specific uses such as:

   • Blast furnace use
   • Open hearth furnace use
   • Converter use
   • Coke oven use
   • Glass kiln use
   • Cement kiln use, etc.

5. Shape and Size: Refractory bricks are classified by their shape and size:

   • Standard-shaped bricks
   • Common-shaped bricks
   • Special-shaped bricks
   • Irregular-shaped bricks
   • Ultra-special-shaped bricks

6. Mineral Composition: Refractory bricks can be classified based on their chemical mineral composition:

   • Silica-alumina bricks
   • Clay bricks
   • High-alumina bricks
   • Semi-silica bricks
   • Silicious bricks
   • Fused quartz refractory products
   • Magnesia bricks
   • Magnesia-alumina bricks
   • Carbon bricks
   • Graphite bricks
   • Dolomite bricks
   • High-hardness stone materials, etc.

These classifications help in selecting the appropriate refractory bricks for various high-temperature applications, taking into consideration their chemical properties, refractoriness, manufacturing processes, and specific uses.