What are the Types of Refractory Cement?

Refractory cement is also called aluminate cement, also known as high-temperature cement. It is made of high-quality bauxite and high-quality lime as raw materials and is mixed into an appropriate amount of raw material in a certain proportion. After sintering, the resulting cooked product has aluminate as the main component. The material is then ground into fine powder to make a fire-resistant hydraulic cementitious material called refractory cement. The refractory degree of refractory cement is not less than 1580 degrees Celsius. According to different compositions, it can be divided into aluminate refractory cement, low calcium aluminate refractory cement, calcium magnesium aluminate cement, and dolomite refractory cement.

Cement is added with special materials used in the preparation of high-temperature resistant (fire-resistant) concrete. There are:

Low calcium aluminate refractory cement with pure bauxite and limestone as the main raw materials.

Dolomite high-temperature cement is made from dolomite as the main raw material and then added with apatite, iron ore, etc.

Materials that can produce chemical reactions and harden at high temperatures, such as high-temperature-resistant cement with refractory sulfates, borates, and phosphates as cementing materials, are used.

Refractory cement product classification

1. Aluminate refractory cement

Also called high alumina cement, it is the most commonly used high-temperature refractory cement. Aluminate refractory cement is a hydraulic cementitious material made from bauxite and limestone as raw materials, clinker with calcium aluminate as the main component, and an alumina content of about 50%, which is obtained by calcination and then ground. Aluminate cement is often yellow or brown, but also gray. The main minerals of aluminate cement are monocalcium aluminate (CaO·Al₂O₃, abbreviated as CA) and other aluminates, as well as a small amount of dicalcium silicate (2CaO·SiO₂). It is used to cement various refractory aggregates (such as corundum, calcined high alumina bauxite, etc.) to make refractory castables or refractory concrete for lining industrial kilns.

Compared with low calcium aluminate refractory cement: early strength is higher, refractory degree is close, and use is the same. The main purpose is to prepare refractory concrete, which can be used to line various high-temperature furnace linings. It is especially suitable for furnaces with special-shaped structures that are difficult to build with refractory bricks.

2. Low calcium aluminate refractory cement

It is made of high-quality alumina and high-quality limestone as raw materials, which are mixed into raw materials with appropriate ingredients according to a certain proportion. After sintering, the resulting clinker with low calcium aluminate as the main component is ground into fine powder. A fire-resistant hydraulic cementitious material called low-calcium aluminate refractory cement.

Compared with high alumina cement, the main differences are high alumina content, low calcium oxide content, low early strength, and high refractoriness. It can be formulated into refractory concrete or refractory mortar with refractory aggregates (such as calcined bauxite, high alumina brick fragments, etc.) with a refractory temperature of 1770°C or above, and can be used as the lining of cement rotary kilns and other industrial kilns.

3. Calcium magnesium aluminate cement

Calcium magnesium aluminate cement is made from high-quality bauxite and dolomite in an appropriate proportion, sintered, and ground.

Compared with low-calcium aluminate cement, calcium-magnesium aluminate cement has the following advantages: strong resistance to chemical erosion of slag and metal melt; under the same alumina content, due to the presence of spinel, fire resistance The strength is higher; the mixing water is less, the porosity is lower after hardening of the cement, and the calcination shrinkage is small; the strength loss when heated to 1100°C for dehydration is small. Calcium magnesium aluminate cement fused white corundum and other aggregates are formulated into concrete, which can be used as the lining of cement rotary kilns and other industrial kilns.