Process and device for forming dense layers in a gypsum slurry

摘要

A process for manufacturing plasterboard, comprising the following steps: feeding hydratable calcium sulphate and water into a first mixer and feeding hydratble calcium sulphate and water into a second mixer, where these first two feeding steps are carried out independently one from the other; feeding in a facing; preparing a first gypsum slurry in the first mixer; preparing a second gypsum slurry in the second mixer; applying the first gypsum slurry onto the facing and forming a crude surface layer; applying the second gypsum slurry onto the crude surface layer and forming a crude core layer that has a different composition to that of the crude surface layer; feeding hydratable calcium sulphate and water into a third mixer and preparing a third gypsum slurry, where the hydratable calcium sulphate and water are fed independently from the other two mixers, said first and third gypsum slurries being prepared in separate mixers; using the third gypsum slurry and forming a second crude surface layer with a higher density than that of the crude core layer; forming the facing and the gypsum layers into a crude plasterboard; and hydrating and drying the plasterboard, is disclosed. A device for manufacturing plasterboard is also disclosed.