Abstract Thermo-oxidative degradation of mollusk shells to CaO through intermediate phase of CaCO3 has been investigated using various analytical techniques. Powders of shells species (Dosinia exoleta and Ostrea edulis), with particle size fractions of 0.045 – 0.125 mm, 0.125–0.2 mm, and 0.2–1 mm, were subjected to degradation at the various heating rates (5, 10, 15 and 20 °C min−1). Degradation pathway of this carbonate-rich waste material has not yet been analyzed in detail at particulate level. Understanding transformation process in air should lead to control over yield and morphology of final product. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) techniques were used to benchmark transformation steps at different heating rates and final decarbonation temperatures, while scanning electron microscope (SEM) was used to analyze the effect of temperature on evolution of morphological changes for particles of different fractions. It was found that sintering in the presence of carbon dioxide (CO2) could be triggered by agglomeration of CaO crystals, enhanced by CO2 adsorption that increases surface energy.

中文翻译：

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用于商业部门的贝壳废物的热氧化演化和物理化学表征

摘要 已经使用各种分析技术研究了软体动物壳通过 CaCO3 中间相的热氧化降解为 CaO。贝壳物种（Dosinia exoleta 和 Ostrea edulis）的粉末，其粒度分数为 0.045 – 0.125 mm、0.125–0.2 mm 和 0.2–1 mm，在不同的加热速率（5、10、15 和 20 °C min−1)。这种富含碳酸盐的废物的降解途径尚未在颗粒水平上进行详细分析。了解空气中的转化过程应该可以控制最终产品的产量和形态。使用热重分析 (TGA) 和 X 射线衍射 (XRD) 技术对不同加热速率和最终脱碳温度下的转化步骤进行基准测试，而扫描电子显微镜（SEM）则用于分析温度对不同组分颗粒形态变化演变的影响。发现在二氧化碳 (CO2) 存在下的烧结可以通过 CaO 晶体的团聚触发，通过增加表面能的 CO2 吸附增强。