When heating and calcining the dehydrate gypsum and chemical gypsum (ardealite, desulphurization plaster, fluorgypsum), the dehydrate gypsum was decomposed, we get the semi-hydrated gypsum, i.e., plaster of Paris.

According to the temperature and pressure during decomposition, the products
include high intensity gypsum and plaster of Paris.

They are the same in the process of mechanization manufacture the plaster of Paris. The plaster breaking system, calcined system and grinding aging system are the main parts.