Chromatic Classification of Ouargla (Algeria) Dunes Sand: Determination of Main Compositions and Color Causes, by Using XRD, FTIR and XRF

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• 作者：Naouia Mahdadi ; Smaïl Chihi ; Hamza Bouguettaia ; Samiha Beddiaf…
• 关键词：Dunes sand ; Chromatic classification ; XRD ; FTIR ; XRF ; Quartz ; Calcite
• 刊名：Silicon
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：9
• 期：2
• 页码：211-221
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Inorganic Chemistry; Materials Science, general; Optics, Lasers, Photonics, Optical Devices; Environmental Chemistry;
• 出版者：Springer Netherlands
• ISSN：1876-9918
• 卷排序：9

文摘

In the present work, a manually chromatic classification of Ouargla dunes sand has been carried out. According to its visual color, eight chromatic types of sand have been obtained: transparent (yellow, orange and red), and opaque (white, milky, gray, black and red). According to the main chemical compositions of sand, both XRD and FTIR have divided the chromatically sorted sand into three groups: quartzite (transparent samples), calcareous (milky, gray and black opaque samples) and calcareous quartzite (white and red opaque samples), without possibility of distinguishing between the sorted samples. FTIR spectroscopy has shown all functional groups and vibration modes in these samples. XRF spectroscopy has shown that sand grain colors are closely related to the main compositions as well as the impurities. It has also been shown that transparent samples contain more than 92 % of quartz (SiO ₂). The redness of transparent samples is proportional to iron (Fe) impurities. It has also been shown that milky, gray and black opaque samples contain more than 55 % of calcium oxide (CaO). The milky color is due to magnesium (Mg) and sulfur (S), whereas the blackness is due to iron (Fe) and manganese (Mn). Both white and red opaque samples contain approximately equal concentrations of quartz and calcite, whilst the redness refers to the high concentration of iron (Fe), whereas the whiteness is due to the presence of magnesium (Mg).