COMPARATIVE INVESTIGATIONS INTO THE SEDIM ENTATION AND RHEOLOGY OF NON-FORMULATED MULTIPHASE GYPSUM PLASTERS MADE FROM NATURAL AND FGD GYPSUM

The behaviour of industrial multiphase gypsum plasters in aqueous susp ensions was investigated. The particle disintegration of the gypsum pl aster grains in water was clearly established, and was particularly dr amatic for the larger grains. The ''sinking'' of finely divided FGD gy psum is attributable to the lack of a very fine particle fraction. In essence, the rheological differences between FGD gypsum and natural gy psum can be attributed to differences in particle size distribution. T his underlines the outstanding importance of particle size distributio n for the application properties of gypsum plasters.