How to control the properties of semi-aqueous plastering gypsum?
In general, the hemihydrate gypsum produced is often a mixture of hemihydrate gypsum and type III anhydrite.
Type III anhydrous gypsum, also known as dehydrated hemihydrate gypsum, has the same crystal phase structure as the original hemihydrate gypsum.
Type III anhydrous gypsum will quickly hydrate into hemihydrate gypsum when it meets the moisture in the air.
This unstable phase is unavoidable in the production of hemihydrate gypsum. If you don’t pay attention to this point, it is easy to cause the instability of plastering gypsum when using hemihydrate gypsum to prepare plastering gypsum.
The main performance is that when the same retarder content is used, the setting time of each batch of plastering gypsum is different. The reason is that type III anhydrous gypsum in hemihydrate gypsum acts as a coagulation accelerator during the hydration process of gypsum. When the proportion of type III anhydrite in hemihydrate gypsum is different. The coagulation effect is also different. This is the main reason why many manufacturers cannot obtain products with stable performance when using hemihydrate gypsum to prepare plastering gypsum.
The most important thing in the production of semi-aqueous plastering gypsum is to control the quality of the semi-aqueous gypsum. Stabilize the properties of hemihydrate gypsum. Choose a retarder that does not affect strength and a high-efficiency water-retaining agent.
HPMC produced by Landcel can be used in gypsum as an additive. Effectively improve the water retention of gypsum. Welcome to consult for free samples.