EXPERIMENTAL INVESTIGATION IN THE VARIATION OF SOAPSTONE AND GRANITE ROCKS AS THERMAL ENERGY STORAGE MATERIALS

To determine the suitability of granite and soapstone rocks as materials for thermal energy storage in solar drying and concentrated solar power generation experimental investigation was conducted. Characterization experiments on thermal chemical, thermophysical and mechanical properties were conducted. Whereby, thermal stability was determined using the thermal gravimetric analyzer (TGA); crystalline phases were studied using the X-ray diffraction (XRD); structural analysis was studied through the petrographic imaging. Moreover, chemical composition was determined using the X-ray fluorescence (XRF) and; high temperature test was done in the high temperature furnace. The thermo-physical properties included density and porosity studied using the displacement method; specific and thermal capacity experimented using the differential scanning calorimetry (DSC) and; thermal diffusivity and conductivities determined through the laser flash apparatus (LFA). The thermo-mechanical properties studied were the Young’s modulus obtained using the nano-indentation method. Sample codes depending on rock type and geotectonic setting of origin - Soapstone from Craton geotectonic setting CS - Soapstone from Usagaran geotectonic setting US - Granite from Craton geotectonic setting CG - Granite from Usagaran geotectonic setting UG为评估花岗岩与皂石作为太阳能干燥及聚光太阳能发电领域储热材料的适用性，本研究开展了相关实验探究。针对两类岩石的热化学、热物理及力学性能，开展了系列表征实验：其中，采用热重分析仪（TGA）测试热稳定性；利用X射线衍射（XRD）分析晶体相组成；通过岩相成像开展结构表征。此外，采用X射线荧光光谱（XRF）测定化学成分，并在高温炉中完成高温性能测试。热物理性能涵盖采用置换法测试的密度与孔隙率；利用差示扫描量热法（DSC）测定的比热容与热容量；以及通过激光闪射仪（LFA）获取的热扩散率与导热系数。热机械性能方面，采用纳米压痕法测试得到杨氏模量。样品编码依据岩石类型及其产出的大地构造背景制定：克拉通大地构造背景皂石（CS）、乌萨加拉造山带大地构造背景皂石（US）、克拉通大地构造背景花岗岩（CG）、乌萨加拉造山带大地构造背景花岗岩（UG）