Action of fluoropgypsum in anhydrite screed

Synthetic anhydrite also comes from industrial production. It is formed during the production of hydrofluoric acid. Hydrofluoric acid consists of sulfuric acid and fluorite. In a rotary kiln, the two substances react at 300 to 600 °C to form hydrofluoric acid on the one hand and calcium sulfate on the other. Quicklime or hydrated lime is used to neutralize anhydrous synthetic anhydrite. The bulk material is broken up, finely ground and stored in silos after an activator is added. The use of desulfurized gypsum and synthetic anhydrite as a supplement to natural raw materials is easy to master in terms of process technology and represents a good example of a higher level of recycling in terms of a sustainable circular economy. Anhydrite ironing plate (AE) or calcium sulfate ironing plate (CA) is a type of ironing plate consisting of an anhydrite binder, aggregate (maximum particle size 8mm) and added water. Calcium sulfate mortar is also called gypsum mortar because the calcium sulfate in the fully hardened mortar has a fully hydrated crystal structure. Appropriate additives may be included to improve processing. The anhydrite mortar will be walkable about two days after installation, and only slightly loaded after five days at the earliest. It cannot be exposed to permanent moisture pressure, which is why it is particularly suitable for dry areas of buildings. Anhydrite mortar has a lower strength than cement mortar and can therefore withstand less heavy loads. [1] A further development was the anhydrite flow-ironed plate (AFE). Because of its liquid consistency, it can be flat on its own. In addition, due to the low tension during drying, even in areas up to 1,000 square meters (if no floor heating is installed). The main component is anhydrite, which acts as an adhesive, which hydrates quickly with water to form gypsum (calcium sulfate dihydrate) and solidifies in the process. Synthetic anhydrite is commonly used, which is obtained by burning gypsum, such as FGD gypsum, from the flue gas purification of power plants. Mineral (granular) natural anhydrite is also rarely used. Limestone and quartz sand are used as aggregate.Because anhydrite mortar is very susceptible to moisture, it should only be used in damp rooms (such as private bathrooms, kitchens and toilets) to prevent possible splashing (for example by painting or applying an elastic adhesive). Otherwise, it can be used indoors in all areas of residential and commercial buildings, whether in new construction or in renovation. It can also be laid seamlessly over large areas due to its low shrinkage. Anhydrite mortar is laid in floating, separate layers and combinations. To get a flat surface, flatten, rub and smooth it with the help of a level.Fluogypsum can be used as the binder of mortar instead of traditional cement. Because of its good fluidity and many other advantages, it is widely used in the application of floor screen Self-leveling, good dimensional stability, high mechanical strength, good thermal performance.