Study of the Physical and Structural Properties of Some Local Mineral Clays and Effect of Doping with Chromium Oxide

Abstract

Chemical composition, physical properties andstructural characterization of local natural clays which have been collectedfrom Aski Mosul village, area around Mosul city/ Iraq, were studied. The studyapproach is based on using x-ray diffraction, x-ray florescence, atomicabsorption, thermal gravimetric analysis, differential scanning calorimetry,infrared spectroscopy, instrumental and classical chemical analysis techniques.Chemical composition studies of the natural sample clearly indicating the presenceof large amounts of silica and calcium oxide in addition to aluminum oxide andother minor oxides. Moreover, it is shown that such sample yields (⁓5%)amorphous silica on treating with basic medium. The results were compared withthose obtained from acidicaly treated and chromium oxide doped clay samples. Oncomparison the physical properties (e.g density, porosity, water absorption,pore size, and capillary action), it seems that the treated clay sample has lowdensity and high porosity and permeability. Moreover, the doped samples aremore dens than others. Such variation because of the elimination of carbonatecompounds on treating and doping processes. Four samples were prepared in order to be more active and selectiveadsorbent materials. Soxhlate fractionating techniques were set for all theabove types of adsorbents using four eluants gradually increased in polarity.The fractionation results showed significant variations in the fractionsisolated according to their polarities as indicated by percentage results.