Separation and identification of minerals composing the Tunisian silica sands have been conducted by acid etching and hot filtration/sedimentation (HFS) without affecting the quartz component. It was found that the hot acid etching process is an effective method to separate quartz and clay minerals in the silica sand. The SEM micrographs of the silica sand show rough surface and some cracks with irregular shapes. The surface becomes clean and smooth after acid etching process. After chemical dissolution, the clay minerals were recovered by hot filtration following by sedimentation at low temperature. FT-IR, EDS maps, and secondary electron (SE) analyses of separated clay minerals reveal the presence of Fe2O3, montmorillonite, and kaolinite minerals. The LIBS analysis of clay minerals shows the presence of Al, Fe, Ca, Al, and Mg. The sequential etching process can be introduced in the purification methods as an effective way to separate quartz from clay minerals.

中文翻译：

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组成硅砂的矿物的分离和鉴定（突尼斯西南部）

组成突尼斯硅砂的矿物的分离和鉴定是通过酸蚀刻和热过滤/沉淀 (HFS) 进行的，而不会影响石英成分。结果表明，热酸蚀刻工艺是分离硅砂中石英和粘土矿物的有效方法。硅砂的SEM显微照片显示出粗糙的表面和一些形状不规则的裂缝。酸蚀处理后表面变得干净光滑。化学溶解后，粘土矿物通过热过滤和低温沉淀回收。FT-IR、EDS 图和分离出的粘土矿物的二次电子 (SE) 分析揭示了 Fe2O3、蒙脱石和高岭石矿物的存在。粘土矿物的 LIBS 分析表明存在 Al、Fe、Ca、Al 和 Mg。