Screening machines for finest sifting of gypsum

In chemical terms, gypsum is defined as calcium sulfate (CaSO4 • 2H2O). Natural gypsum occurs as solid material and as a fine powder in various colors. In the past, gypsum was mainly extracted by mining, but today the amount gained from flue gas desulfurization, the so-called flue gas gypsum, is increasing.

Gypsum is sifted for the first time directly after the mining process. Problems for the sifting process arise when the material binds moisture and begins to stick. A direct excitation of the screen cloth, as used on our vibration screening machines, offers major advantages in this case: Sticking plaster is effectively knocked off the mesh.

The static machine housing represents a further advantage of direct screen excitation. Flange connections and dedusting systems can be tightly screwed and sealed. Dust handling is therefore excellent and the entire system remains significantly cleaner.

Screening of building products containing gypsum

After burning the gypsum, it is often mixed with other building materials. The grain size of the gypsum must be classified accordingly. For this purpose, the burnt plaster is ground and sifted. Coarse-grained material is not desired in building products, because it reduces the processability. It must therefore be removed from the building material by fine screening. Thereby high specific screening capacities with fine separation and small machine sizes are required. These requirements in combination with the low bulk density of the fine gypsum powder are challenging for the screening technology. RHEWUM screening machines achieve highest accelerations directly at the screen mesh and can therefore reliably separate even finest gypsum powder at high throughputs. This is exactly why our high-performance screening machines are used by all major gypsum manufacturers in Europe.

If space is limited in a production plant RHEWUM's model RHEsonox^® is a good option. With a flat design, a  RHEsonox^® produces excellent screening results and offers all the advantages of direct screen excitation.