Refractory bricks are also called fire bricks, they are made of refractory clay or other refractory materials. They are yellow or brown, mainly used for smelting furnaces, and it can withstand high temperatures of 1580 - 1770 ℃.Refractory material is generally divided into two types, namely, unshaped refractory and shaped refractory.Unshaped refractory material: also called castables, is a mixed powder consisting of a variety of aggregate and one or more kinds of adhesive .It must be mixed with one or more liquids when used, and it has good fluidity. Shaped refractories: general system of refractory brick, the shape of the standard rules, can also be temporarily processed when required.

The process of making refractory bricks：

Firebrick is made of 50% soft clay and 50% hard clay clinker. The bauxite ore is firstly used, and the ingredients are sorted according to a certain granularity requirement, broken into certain granules by a crusher, an appropriate proportion of kaolin clay is added, and a considerable size of firebrick brick embryos are pressed and pressed by a press to form and dry. After the firing in a tunnel kiln at a high temperature (1200 to 1400℃), it is necessary to pay attention to rapid cooling during the firing process, and to rapidly cool the temperature at 800 to 1000 ℃until the end of the cooling process.

Classification of refractory bricks：

1 .High-alumina brick: AL2O3 content is more than 75, the refractoriness is higher than that of clay brick, and it is resistant to acid and alkali corrosion. It is suitable for cement kiln burning zone, etc. It has long service life but high price.

2. Dolomite brick: Hanging kiln skin has good performance and good corrosion resistance, but there are many bricks with f-CaO, which are easy to hydrate, difficult to transport and keep, and less used in production.

3. Magnesia chrome brick: more used for burning zone, the disadvantage is that the thermal shock resistance is poor, plus the six price Cr is highly toxic, the international production and use of magnesia chrome brick countries gradually reduce, now use this brick production units to find alternatives as soon as possible.

4. Spinel brick: mainly used for transition zone, good seismic performance, resistance reduction and good refractoriness but almost a little.

5. Anti peeling brick: the brick contains a small amount of ZrO. It has a martensitic phase transition to form fine cracks during the process of heating. It has strong anti alkaline, anti peeling resistance and good slag resistance.

6. Phosphate brick: Refractory degree is low, but the intensity of heat shock resistance, used for grate cooler kiln hood, etc.

7. Silicon carbide bricks: high temperature resistance, small coefficient of thermal expansion, resistance to quenching, hot heat and abrasion resistance are all suitable for cooling belts and kiln mouths.

8. Silicon brick: with good thermal shock, high strength, good wear resistance, suitable for excessive belt.