Ceramics-Silikáty 54, (2) 152 - 159 (2010)

The phosphogypsum – dihydrate calcium sulphate is waste material of phosphoric acid production from the Kola apatites. The possibility of applying lime neutralized phosphogypsum as a raw material for obtaining anhydrite binder was investigated in this paper. The effect of the calcination temperature and of following additives: dust from a cupola furnace, ground glass and clay on the properties of obtained product was studied. The products were characterized by X–ray diffraction analysis, simultaneous thermal analysis, Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) analysis. It was determined that the phosphogypsum with additives calcined at the temperature 900°C, and the following grinding of it to the specific surface area 600 ± 10 m²/kg allow obtaining the fast setting anhydrite binder. The anhydrite binder calcined with the addition of 5% ground glass exposes the best physical and mechanical properties: the setting duration up to 13-38 min, the compressive strength of the dry samples is 30.74 MPa.