Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Inorganic Chemistry

Sinai basaltic rocks and by-pass cement dust from Misr Beni{u2013}Suef plant in Egypt were examined for use in preparation of technical glass-ceramic materials. Six base glass batches were studied from these basaltic rocks and cement waste materials. The compositions studied were designated G0, G10, G20, G30, G40 and G50, where the number indicated the wt% content of cement waste component and the rest being basaltic rocks. These batches were melted in alumina crucibles in an electrically heated globar furnace at temperatures ranging from 1400 - 1450{u00B0}C and then casted into rod and disc shapes and subjected to heat- treatment. Many important techniques were used in the present study including differential thermal analysis (DTA), X- ray diffraction, scanning electron microscope, indentation micro hardness, thermal expansion, bending strength etc. The obtained glass ceramic materials were mainly composed of diopside, gehlenite, magnetite and anorthite with uniform crystal size is below 150 nm as shown by SEM. The effect of some selected nucleant agents on the mineralogical constituents and microstructures of the studied glasses were carried out in the batch G30, the nucleating agents used in that study are Cr₂O₃, ZrO₂ and CaF₂. The presence of Cr₂O₃, ZrO₂ and CaF₂was found to enhance the crystallizability and favored wollastonite and quartz formation and retarded the formation of gehlenite. Cr2O₃ and ZrO₂ are much better than CaF₂ in promoting homogeneous nucleation and growth of extremely fine-grained microstructure of aluminous pyroxene, wollastonite, quartz and magnetite with uniform crystal size is below 50 nm in glass containing Cr₂O₃. The final materials possessed high values of mechanical properties, hardness ranging from 4077 to 6791 MPa, bending strength values ranging from 75 and 141 MPa, with high chemical durability and zero water absorption, which allow them to be convenient for many useful applications, such as building materials, ceramic tiles, etc.

Issued also as CD