Technological Potentials of Using a Rotary Vortex Unit for Obtaining Gypsum Binder.

It is shown that a rotary vortex thermal unit can be used in order to produce a high quality gypsum binder (fast-setting A grade gypsum) including the utilization of gypsum-containing wastes taken from gas cleaning facilities, with obtaining a marketable product and reducing the accumulation of solid wastes, which should promote solving economic and environmental problems. By varying the maximum roasting temperature and the holding time, controlling both the binding properties of gypsum and its strength has been achieved. These properties are inversely related: as the roasting temperature increases, the binding properties get improved, whereas the strength of the hardened mortar exhibit a decrease. Increasing high-temperature exposure time, on the contrary, leads to worsening gypsum binding properties and improving gypsum strength properties. [ABSTRACT FROM AUTHOR]