APPLICATION OF IR-SPECTROSCOPY FOR STUDY OF ALUMOSILICATE RAW MATERIALS

IR-spectroscopy is an essential tool for the study of the structural features of the material, regardless of its state (amorphous or crystalline). It allows accurately explain the type and character of structural bonds, the presence of certain molecular groups in the material. For the construction material science, this analytic method helps to study raw materials and composite materials, binders, etc. In this paper, using infrared spectroscopy silicate rocks consisting of the most common minerals in the Earth. The variety of species and types of bonds in the structural units of silicates influent on the energy of the molecular groups, the differences of which are reflected as certain absorption band in IR-spectra of these compounds. Sedimentary aluminosilicate rocks investigated in, silicon were divided into two groups according to the chemical composition and the numerical aluminum-silica oxides ratio. According to XRD-analysis it is polymineral advantageously silicate systems, consisting of both crystalline phases (quartz, clay minerals (kaolinite, montmorillonite, illite), mica, and feldspar) and X-ray amorphous ones. The main differences between these groups in the mineral composition are reflected in the clay phase composition and the presence of impurities. First group of the rocks (with a high Al2O3/SiO2) is characterized by the predominance of layered aluminosilicate kaolinite, the second one is presented by montmorillonite and cristobalite-tridimite opals from the remains of ancient algae. The goal of the research was to study the composition, type and type of the structural bonds in the studied rocks with IR-spectroscopy as well as comparison of data obtained by different analytic methods and the establishment of the relationship/ A similar mineral composition of the study rocks determines the presence in the IR-spectra of the same absorption bands. However, the form of profiles, the width of the bonds and their intensities indicate the presence of various silicate and aluminosilicate molecular groups, as well as water in different states. Found that the different chemical and mineral composition of the materials have a significant impact on the type of the lift-spectra. Predominantly kaolinite-bearing rocks are characterized by the predominance of layered aluminosilicate structural groupings Q(3). The second group of studied materials is different, the first, in the displacement of vibration frequency of bridge bond for layered anions to the region of larger wave numbers and secondly, in the increase in the intensity of the absorption bands of frame groups Si-O-Si (Q(4)). This is consistent with the decrease of aluminum structures and in the prevalence of frame structure (quartz and cristobalite-tridimite-opals). Interpretation of the others absorption bands in the "fingerprint" region of IR-spectra confirm the differences and diversity of composition. Analysis of the spectra showed the presence of water attributed to its presence in adsorbed form, as well as in form of OH-groups on tops of silicon tetrahedra in the structure of aluminum-oxygen octahedra. On the OH- groups of layered silicates according to mechanism of the formation of hydrogen bonds the adsorption of water or other substances with the oxygen atoms on the surface is possible.