FLUOROHYDRITE COMPOSITIONS WITH DISPERSED FILLERS

The article explores physical and mechanical properties of a structural and thermal insulation composition based on a high–strength anhydrite binder prepared on the basis of fluorohydrite, waste from the production of hydrofluoric acid, ex-panded perlite sand and chrysotile asbestos fiber of 7-370 grade from the Bazhenov deposit. 3% aqueous solution of sodi-um phosphate Na3PO4 was used to activate the processes of anhydrite binder structure formation. Expanded perlite sand with average grain size of up to 1 mm was used as an ultralight filler. The microstructure studies and X-ray diffraction analysis showed the presence of a physical and chemical interaction between two-water calcium sulfate and particles of expanded perlite sand, which provides an increase in the physical and mechanical characteristics of the developed material due to the formation of a dense structure of the anhydrite matrix. Crystalline hydrates in the interphase zone at the bounda-ry of the anhydrite binder and particles of expanded perlite sand, in combination with short-fiber asbestos, additionally provide improved physico-mechanical properties of the composition. The applied methods of physico-chemical analysis, including thermal analysis, IR spectroscopy, scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS), identified the structure and interphase interactions between the components of the fluorohydrite composition. The developed composition can serve as a cheap substitute for gypsum in the production of "warm plaster", plasterboard, partition blocks, wall blocks, in the manufacture of architectural details by mold casting, as well as performing thermal insulation of walls in frame construction, including filling for cavity wall construction.