Abstract The present study aims to evaluate the potentiality of 7 selected structural highly ordered kaolinite-rich samples from Egyptian Carboniferous sedimentary deposits (located at Abu Zenima district, west central Sinai peninsula) to use them in medicinal semisolid formulations as peloids. The effect of particle geometry and kaolinite crystallite size are studied to check their influence on thermal dosage performance. The studied samples exhibit a variable mineralogy. Kaolinite is the main constituent (ranging from 81 to 94%), followed by quartz (up to 14%), lesser amounts of anatase and halite, and traces of hematite, magnetite, alunite and gypsum. The kaolinite order “Hinckley Index” varies from 1.28 to 1.50. 1:1 (w/w) kaolin mud pastes were prepared with purified water in Eppendorf tubes using a touch vibration vortex mixer for 2 min. The cooling kinetics of pastes were measured by using a differential scanning calorimetry equipment (Shimadzu DSC-50Q). Specific heats were calculated, following Cara et al. (2000). The granulometry and geometric surface area were measured by laser diffraction (Mastersizer 2000LF, Malvern Instruments) in the range 0.02 and 1500 μm. All analyzed samples showed a clear predominance of particles under 4 μm (ranging from 82 to 94%), with median size (D50) ranging from 0.93 to 1.35 μm. The heat retention time during cooling from 50 °C to 32 °C reached up to 30.82 min, oscillating around an average of 28.72 min, and the temperature corresponding to the minimal dosage time (T20) was not exceed below 34.7 °C. A good correlation (R2 = 0.875) was found between heat retention time and specific heats. There is no correlation between kaolinite content and thermal properties, but R2 values around 0.6 are found with granulometry (finer the particles, greater the heat retention time t32 and the specific heat). Even if sample H5 (Gabal Hazbar deposit) is not the richest in kaolinite, it exhibits the best thermal dosage performance, in accordance with the granulometry (D50 = 0.93 μm), and geometric surface area (3.73 m2/g).

中文翻译：

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一些埃及高岭土糊剂用于骨疗应用的热特性：颗粒几何形状对热剂量释放的影响

摘要 本研究旨在评估来自埃及石炭纪沉积矿床（位于西奈半岛中西部的阿布泽尼马区）的 7 个选定的结构高度有序的富含高岭石的样品在药用半固体制剂中用作药丸的潜力。研究了颗粒几何形状和高岭石微晶尺寸的影响，以检查它们对热剂量性能的影响。研究的样品表现出不同的矿物学。高岭石是主要成分（范围为 81% 至 94%），其次是石英（高达 14%）、少量锐钛矿和岩盐，以及痕量的赤铁矿、磁铁矿、明矾石和石膏。高岭石阶“欣克利指数”从 1.28 到 1.50 不等。1:1 (w/w) 高岭土泥浆用纯净水在 Eppendorf 管中使用触摸振动涡旋混合器制备 2 分钟。通过使用差示扫描量热设备（Shimadzu DSC-50Q）测量糊剂的冷却动力学。按照 Cara 等人计算比热。(2000)。粒度和几何表面积通过激光衍射（Mastersizer 2000LF，Malvern Instruments）在 0.02 和 1500 μm 范围内测量。所有分析的样品都显示出 4 μm 以下颗粒的明显优势（范围为 82% 至 94%），中值粒径 (D50) 范围为 0.93 至 1.35 μm。从50℃冷却到32℃的保温时间达到30.82min，平均在28.72min左右振荡，最小投加时间（T20）对应的温度不超过34.7℃以下。在保温时间和比热之间发现了良好的相关性 (R2 = 0.875)。高岭石含量与热性能之间没有相关性，但通过粒度测定发现 R2 值约为 0.6（颗粒越细，保温时间 t32 和比热越大）。即使样品 H5（Gabal Hazbar 矿床）的高岭石含量不高，根据粒度（D50 = 0.93 μm）和几何表面积（3.73 m2/g），它也表现出最佳的热剂量性能。