What is refractory cement?

Refractory cement is also called aluminate cement and high temperature cement. Aluminate cement is made from bauxite and limestone as raw materials, burnt clinker with calcium aluminate as the main component and an alumina content of about 50%, and then crushed into hydraulic cement material, refractory cement is often yellow or brown in color, but also gray. Heat-resistant cement is commonly used for lining industrial furnaces.

Classification of refractory cement

Refractory cement can be divided into aluminate refractory cement, low calcium aluminate refractory cement, aluminate calcium magnesium cement and dolomite refractory cement depending on different components.

1. Aluminate Refractory Cement

Aluminate Refractory Cement – This, as a rule, refractory cement, obtained by mixing and grinding low calcium aluminate refractory cement clinker and high alumina cement clinker. Compared to Low Calcium Aluminate Refractory Cement: higher initial strength, similar fire resistance and continuous use.

2. Low Calcium Aluminate Refractory Cement

Low calcium aluminate refractory cement is made from high quality bauxite and limestone in appropriate proportions, sintered and crushed.

3.Calcium magnesium aluminate cement

Calcium-magnesium-aluminate cement is mainly made from high quality bauxite and dolomite in appropriate proportion, sintered and crushed. The composition of calcium-magnesium aluminate cement is usually as follows: aluminum oxide ranges from 66% to 74%, calcium oxide – from 13% to 18%, and magnesium oxide – from 10% to 13%. Traces of silicon dioxide and iron oxide. Mineral composition – calcium aluminate, with calcium aluminate ranging from 45 to 60%, and spinel – from 35 to 50%. Fire resistance above 1650°C.

3. Dolomite refractory cement

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

What are the technical requirements for the production of high temperature cement?

• Fineness of high temperature cement: The smaller the cement particles, the larger the specific surface, the faster and more sufficient the hydration reaction and the higher the early and subsequent strength.
• Setting time of high temperature cement: To ensure there is sufficient time to complete various processes, such as mixing, transportation and forming during construction, the initial setting time of the cement should not be too short; there is hope after construction is completed, that the cement can harden as quickly as possible to give strength, therefore the final setting time should not be too long. The initial setting time of fire-resistant cement should not exceed 45 minutes, and the final setting time should not exceed 390 minutes.
• Volume stability of refractory cement: The uniformity of changes in the volume of the cement mass during the process of setting and hardening is called the volumetric stability of cement. If the volume change occurs unevenly, volume stability remains low, and deformation and cracking are also possible, which reduces the quality of the project and even leads to accidents.

What problems should you pay attention to when firing refractory cement kiln lining?

2. At room temperature 350°C, more likely, this will lead to local spikes, Therefore, special attention should be paid to slow baking. If there is still a lot of steam produced after holding at 350°C, the heating rate should still be reduced.
3. In conditions of poor ventilation and difficult removal of water vapor, the holding time should be increased accordingly.
4. When baking with fatty oil, you must strictly ensure that, to prevent fatty oil from splashing on the surface of the furnace lining, to prevent partial rupture.
5. When baking with wood, direct contact with the flame often causes localized heating to occur too quickly., therefore it should be protected.
6. For newly poured refractory cement, it can be baked through at least 3 day.
7. Cooling of the refractory cement lining should also be slow, and forced ventilation should be avoided.

Rongsheng Monolithic Refractory Plant

Rongsheng Monolithic Fireproof Materials Factory – this is a company, producing refractory materials for furnaces. Monolithic refractories produced include cast products, castings with low cement content, materials for tamping and plastics. We support custom made fireproof products and can send samples for free.