Abstract:
Two Sudanese mica samples were collected from Shereik, River Nile State and Red Sea State. A systematic series of analysis were performed to characterize the micas and to study effects of impurities on physical, mechanical, thermal, and electrical properties.
The classical methods namely gravimetric and volumetric analysis were used for the determination of the major and impurities constituents, SiO2 was 40.03% - 39.02%, Al2O3 was 35.54% - 36.01%, K2O was 18.16% - 18.05% , Na2O was 0.37% - 0.54%, while by Inductively, Coupled Plasma Optical Emission Spectroscopy (ICPOES) SiO2 was 40.49% - 39.90%, Al2O3 was 37.53% - 35.78%, K2O was 19.51% - 20.09%, Na2O was 0.50% - 0.38%. Using Flame Photometry Emission (FE) K2O was 16.76% - 18.00%, Na2O was 0.40% - 0.34% and Atomic Absorption Spectroscopy (AAS) K2O was 31.06% - 29.24%, Na2O was 0.55% - 0.61%.
The supplementary techniques, Energy Dispersive X–ray Fluorescence (EDXRF) SiO2 was 36.01% - 35.49%, Al2O3was 33.79% - 35.97%, K2O was 27.93% - 26.40%.
The X – ray diffraction (XRD) revealed that mica samples were composed of mica minerals in addition to quartz and kaolin impurities.
Thermogravimetry (TG) curves evident that a slight loss of weight (0.15%) was observed at temperature range 1000C– 1050C.
Infrared technique showed very strong absorption band at 3622 cm-1 is an indication of free hydroxyl water , strong band at 762 cm-1 most of the frequencies assigned to the Si – O vibration.
Mechanical studies, showed that mica samples had hardness between gypsum and calcite (2 – 3 Mohs), tensile strength 1734 Kg/cm2 and 1718 Kg/cm2, for samples Modulus of elasticity were between 1380x10-3 – 2015x10-3 Kg/cm2, and between 1392x10-3 – 2070x10-3 Kg/cm2, respectively.
Electrical study showed that mica samples had dielectric constant 2.8 – 4.7 kV/mm.
