Refractory cement, as a building material specially used in high-temperature environments, is widely used in high-temperature equipment in metallurgy, steel, thermal power, petrochemical and other industries. Due to its excellent high temperature resistance and corrosion resistance, it can maintain its strength and stability in high temperature environments. However, during the construction of refractory cement, if it is not strictly operated in accordance with the specifications, it will affect its service life and performance. Therefore, the correct construction method is crucial.

1. Preparation
1. Material preparation
Before construction, first ensure that the quality of refractory cement meets the relevant standards and avoid using expired or substandard materials. Refractory cement usually has different types and specifications. Before construction, the appropriate refractory cement should be selected according to the specific purpose. In addition, the ingredients, water, tools, etc. required for construction should also be prepared in advance.

2. Preparation of the construction environment
The construction environment should be kept clean, dry, and at a suitable temperature. The construction site should be kept away from moisture or exposure to rain to prevent premature hydration of cement. In addition, the temperature of the construction environment should be controlled between 5℃ and 35℃. Too low temperature will affect the hydration process of cement, while too high temperature may cause cement to dry too quickly and affect the hardening effect.

3. Preparation of equipment and tools
During the construction process, commonly used tools include mixers, vibrators, trowels, shovels, measuring tools, levels, etc. Make sure these tools are intact and clean to ensure the accuracy and quality of construction.

2. Mixing and modulating refractory cement
1. The ratio of cement and water
Determine the optimal ratio of cement and water according to the type and use requirements of refractory cement. Generally speaking, the water-cement ratio (the weight ratio of water to cement) of refractory cement should be controlled within an appropriate range. Too much or too little water may affect the strength and fire resistance of cement. For some refractory cements with special requirements, specific additives (such as anti-cracking agents, moisture-proof agents, etc.) may need to be added.

2. Mix evenly
Add refractory cement and water to the mixer in proportion and mix evenly. The mixing time should be adjusted according to the properties of the cement and the ambient temperature, usually 3 to 5 minutes. Ensure that the cement and water are fully mixed to achieve the ideal wetness and fluidity.

3. Testing and adjustment
Before formal construction, it is best to conduct small-scale trial mixing and testing to test the operability, viscosity and adaptability of the mixture. If the mixture is too viscous or too thin, the water-cement ratio should be adjusted appropriately to ensure that it is suitable for construction requirements.

III. Construction process
1. Substrate treatment
The construction of refractory cement is usually carried out on the surface of high-temperature equipment or structures, and the surface treatment is particularly important. Before construction, the surface should be cleaned to remove oil, rust and loose materials to ensure that the surface is flat and clean. For metal surfaces, sandblasting can also be performed to improve the bonding strength of refractory cement.

2. Construction method of refractory cement
Depending on the different requirements of construction, refractory cement can be constructed in different ways:

Plastering method: This is the most common construction method. The refractory cement is evenly applied to the base surface by plastering, which is suitable for thinner refractory layers. During construction, the uniformity and flatness of the cement layer must be ensured.
Pouring method: suitable for refractory layers with complex shapes or large thicknesses. First pour the mixed refractory cement into the mold to ensure that it fills the mold and there are no bubbles. Try to avoid air interlayers when pouring to avoid affecting the strength of the refractory cement.
Spraying method: In some special cases, the spraying method can be used for the construction of refractory cement. The refractory cement is sprayed on the surface by spraying equipment, which is suitable for large-scale and high-efficiency construction.
3. Vibration and tamping
No matter which construction method is used, bubbles should be removed by vibration or tamping to ensure that the refractory cement has good adhesion to the base surface and avoid gaps in the cement layer. Using a vibrator to vibrate the cement moderately can improve the density and strength of the cement layer.

4. Applying and finishing
After construction, the surface needs to be finished to ensure that it is flat and smooth. For the cement layer after application, surface defects should be repaired in time to avoid unevenness or bumps.

IV. Curing and curing
1. Curing environment control
The curing process of refractory cement has certain requirements for temperature and humidity. During the curing period, the ambient temperature should be kept at around 20℃ and the humidity should be moderate. For thick refractory cement layers, you can use methods such as covering with wet cloth to keep them moist to avoid drying too quickly and affecting the strength.

2. Curing time
The curing time of refractory cement is usually 7 to 28 days, and the specific time should be determined according to the type of cement, construction environment and use requirements. During this period, avoid applying excessive pressure to the cement layer or exposing it to an environment with excessively high temperatures to ensure that its strength can be fully developed.

3. Final curing
After the refractory cement is cured, final curing is required to ensure that the cement layer reaches its designed strength and fire resistance. During the curing process, care should be taken to avoid cracks and cracks on the cement surface.

V. Common problems and solutions
Surface cracks: If cracks appear in refractory cement after construction, it may be due to improper water-cement ratio, excessively high construction temperature or insufficient curing. Various factors in the construction process should be checked to ensure the correct proportions and strengthen maintenance.

Poor bonding: Poor bonding may be caused by unclean or improperly treated base surface. The base surface should be thoroughly cleaned before construction to ensure that there is no oil, dust and loose materials.

Insufficient strength: If the strength of refractory cement is insufficient, it may be related to the mixing ratio, uneven mixing or improper maintenance environment. The water-cement ratio and the maintenance temperature and humidity should be strictly controlled.

VI. Summary
Correct construction of refractory cement requires not only a certain level of technical skills of the construction personnel, but also a comprehensive control of the construction environment, material selection and construction methods. Through reasonable preparation, correct construction technology and careful maintenance process, it can ensure that the refractory cement can exert its maximum fire resistance and compressive strength in a high temperature environment, thereby extending the service life and ensuring the safe and stable operation of equipment and structures.