Iranian Journal of Crystallography and Mineralogy
Year:2001 | Volume:8 | Issue:2|Papers Count:5

Crystal size and morphology of zeolite NaA have an important role in its specific use in the industries. Thus, investigation of parameters which influence crystal size and morphology of this compound during the synthesis is very important. Parameters such as intensity of mixing, temperature and aging time of the gel preparation, crystallization temperature and composition ratios are Important in this case. In this study, the influences of SiO2/Al2O3, Na2O/Al2O3 and H2O/Al2O3 ratios and impurity in the gel composition on zeolite NaA crystal size and morphology are investigated. Characterization techniques such as X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) have been used for phase identification, particle size and morphology of crystals throughout this work.

During the excavations of Tappeh Ghalaychi near the city of Bukan in west Azerbaijan province, a number of iron and bronze objects were found that are belonged to the 8th century RC. The corrosion of iron objects were studied after chemical analysis. As these objects have a very high cultural value, chemical analysis by using destructive methods is not possible, therefore scanning electron microscope with energy dispersive X-ray microanalysis (SEM-EDX), which allows analysis without any damaging the objects, was used. Likewise for analyzing the corrosion area of the metal objects, Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) were also used. The results of this research showed that a layer of magnetite which is covered with a layer of hematite exists at the surface of the iron objects. In addition, wuestite and goethite were identified in the corrosion products layers.

The protons on a silica or alumina surface can be replaced by manganese(III) porphyrin cations, Mp(TPP+). Manganese(III) porphyrin supported on silica and alumina can activate dioxygen in the presence of additional NaBH4 or [NBu4][BH4] as an electron source and styrene, affording 1-phenyl ethanol and acetophenone in a 4:1 ratio. When oxidation was applied in a mixture of benzene/ethanol, Mn(TPP+) heterogeneous catalyst was deserted from silica and alumina surface. The oxidation of styrene has also been studied in two phases systems H2O/CH2Cl2 in the presence of NaBH4 and tetra-n-butyl ammonium bromide as a phase transfer catalyst. Manganese(III) porphyrin remained stable and major product was 1-phenyl ethanol, when. dichloromethane used in the presence of catalyst supported on alumina, the only product was 1-phenyl ethanol.

Zonous Kaolinite bearing clay deposit is made by hydrothermal alteration of volcanic rocks mainaly of andesite and dacite. Kaolinite, quartz and calcite are the main mineral compositions. As quartz in the volcanic rocks is cryptocrystalline, it is too difficult to separate it from kaolinite. The physical properties and chemical composition of Zonous ceramic grade kaolinite bearing clay are directly related to its nature and geological formation.The percentage of SiO2 in Zonous clay is higher but the amount of Al2O3 is lower than Diamond kaolinte. For this reason the ceramic products of zonous clays have lower resistance to thermal shocks and module of rupture. High roughness, low plsticity and possible greater deformation during firing (Production of Ceramics) are other reasons for limiting the use of Zonous ceramic grade clays. The percentage of calcium oxide (CaO) in Zonous clay is higher in comparison with Diamond Kaolin but potassium oxide (K2O) which plays as a flux in ceramic products is lower in zonous. The high pereentage of CaO which has a high melting point can raise the viscosity as a result lead to Crack in ceramic products. Finally with these colour properties, the Zonous ceramic grade kaolinite bearing clays, can be used as a filler in paper, paint and rubber industries.

In this research, poly halogene-chalcogene SeCl2ICl was synthesized and the crystal structure was determined by a single crystal X-ray diffraction method. This compound formed at temperature ranges from 70-150°C as ruby-red color and crystallizes in monoclinic crystal system, space group P21/c with 4 molecules per unit cell. Lattice parameters of the compound are: a = 6.088 oA        b = 6.555 oA       C = 16.032 oA              α = γ = 90°           β= 98.02°           V = 633.5 oA3 In addition, D.T.A analysis of SeCl2ICl crystals at temperature ranges from -70°C to 194°C and IR studies in the lower range of 700cm-1 and Raman studies in the lower range of 500cm-1 were also carried out.