Mineralogical and geochemical indicators to determine the usage of Abbasabad bentonite, Saveh, Iran

Bentonite is a rock type primarily composed of the clay mineral montmorillonite. Due to its unique properties, bentonite has a wide range of applications across various industries. The Abbasabad bentonite deposit is located within the Urmia-Dokhtar volcanic belt, and its parent rock is Eocene andesite. A total of ۲۹ samples were analyzed for their major oxides using the X-ray fluorescence (XRF) method, and ۲۵ samples were subjected to qualitative and quantitative mineralogical analysis via X-ray diffraction (XRD). The mineralogical composition of Abbasabad bentonite consists of ۱۹% quartz, ۱۶% plagioclase, ۶% potassium feldspar, ۱۶% calcite, ۱۷% cristobalite, ۲۱% clay minerals, with the remaining ۵% comprising other minerals. Additionally, ۴۴% of the bentonite samples demonstrated an enrichment in quartz and clay minerals, while ۱۰۰% of the samples exhibited a depletion of plagioclase and potassium feldspar compared to the parent andesite rock. Approximately ۸۶% of the original andesite rock has undergone alteration into dacite, rhyolite, and trachyte rocks due to the process of chemical weathering. Based on the ratio of CaO to Na۲O (equal to ۳.۷۹), Abbasabad Bentonite is classified as a calcium-type bentonite. The comparison of the chemical weathering index suggests that the bentonite is a result of intense weathering processes. Furthermore, the results of a student’s t-test comparing the chemical composition of Abbasabad bentonite to that used in agriculture, livestock, poultry, drilling, and ceramic industries indicate that Abbasabad bentonite is suitable for agricultural applications.

کلیدواژه ها:

Geochemistry ، Bentonite ، Mineralogical index ، Enrichment index ، Abbasabad Saveh