Alumina Cement

Product Description:

High alumina cement (formerly known as alumina cement) is a hydraulic cementitious material made from alumina and lime as raw materials, formulated in a certain proportion, and calcined and finely ground to produce aluminate as the main mineral component. It is also known as aluminate cement.

There are various types of high alumina cement, which can be classified into CA-50, CA-70, and CA-80 types based on the differences in aluminum and calcium content. Among them, CA-50 is known for its yellow tone, and its raw materials mainly come from alumina and limestone. CA-70 is favored for its low impurities, superior setting characteristics, and fire resistance compared to CA-50 refractory cement, and is often used as a binder for low cement refractory castables. As for CA-80 high alumina cement, its aluminum content is as high as 80% and it contains α - AL2O3 micro powder, so it often serves as a binder in high-end refractory castables. Thanks to their high aluminum content and low calcium content, these two types of cement can significantly improve the setting speed and medium temperature strength of refractory castables, while extending their service life for later strength.

Features:

1. Fast hardening and early strength: High alumina cement is mainly composed of calcium aluminate, and its early strength increases rapidly. It can reach the standard strength in 3 days and is suitable for emergency repair projects or scenarios with high early strength requirements. ‌‌
2‌‌. High hydration heat: early concentrated release of a large amount of heat, suitable for winter construction, but can easily cause temperature difference stress in concrete, so it is not suitable for large volume engineering or high temperature and humid environments. ‌‌‌‌
3‌. Resistant to sulfate corrosion: Cement stone has a dense structure and low calcium oxide content, with strong resistance to sulfate corrosion and suitable for harsh chemical environments. ‌‌‌‌
4. Excellent heat resistance: Solid phase sintering bonding is formed at high temperatures to maintain stable strength, suitable for refractory concrete (such as metallurgical furnace lining). ‌‌

Technical Parameters:

Precautions and application guidelines for the use of high alumina cement:

1. High alumina cement is strictly prohibited from being mixed with Portland cement or lime, and must not come into contact with uncured Portland cement concrete to avoid instant setting that may prevent construction and affect strength. The mixing equipment must be thoroughly rinsed before use.
2. High alumina cement is not suitable for projects that come into contact with highly alkaline solutions.
3. Due to the fact that the hydration heat of high alumina cement is mainly concentrated in the early stages of release, watering and curing should be carried out immediately from the beginning of hardening, and attention should be paid not to be used for pouring large volume concrete.
4. The later strength of high alumina cement concrete will significantly decrease, so the design should be based on the minimum stable strength. The strength value can be determined by placing the specimen in water at 50 ± 2 ℃ for curing after demolding, and taking the lower of the 7-day and 14 day strength values.
If steam curing is used to accelerate concrete hardening, the curing temperature should be controlled within 50 ℃.
When used in reinforced concrete, the thickness of the steel reinforcement protective layer must be greater than or equal to 3 centimeters.
7. No additives shall be added to high alumina cement without sufficient testing.
8. High alumina cement should not come into direct contact with uncured Portland cement concrete, but can come into contact with Portland cement concrete with demolding strength, but attention should be paid to avoiding long-term moisture at the joint.
The most suitable hardening temperature for high alumina cement is about 15 ℃, and the ambient temperature during construction should not exceed 25 ℃ to prevent crystal transformation and strength reduction. In addition, concrete mixed with high alumina cement is not suitable for steam curing.
10. Due to the influence of factors such as crystal transformation and aging of aluminate gel, the long-term strength of high alumina cement shows a downward trend. Therefore, when used in engineering, the design should be based on the minimum stable strength and its specific value should be determined through experiments.

Packaging Standards and Storage Methods:

Usually, moisture-proof paper bags are used for packaging, which consist of four layers of ordinary packaging paper and three layers of moisture-proof paper to ensure the moisture-proof performance of cement. The net weight standard for each bag is 50 ± 1 kilogram, and packaging can also be customized according to customer needs.