Most carbonation reactions are characterized by products encasing unreacted particles, leading to incomplete reactions and consequently lower material utilization efficiency. This study introduces a novel approach for preparing gradient carbonated materials by partially calcined limestone (PCL), which is calcined below full calcination temperatures to maintain some original limestone while partially transforming into lime. The mechanical strength, phases evolution and microstructure were investigated. The results indicated that the mechanical properties of the materials improve continuously and porosity markedly decreases as the calcination degree of PCL increases, peaking at around 35 %. However, excessive calcination degree impedes the formation of a compact structure. Simultaneously, the carbonation process yields CaCO with a lower decomposition temperature, exhibiting two distinctive microstructural features: an encapsulating layer on the surface of unreacted limestone and the tiny particles (<5 μm) scattered between the layers. This study presents a promising approach to carbonated material design, demonstrating that through controlled partial calcination of limestone, opening avenues for more efficient material utilization.

中文翻译：

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部分石灰石煅烧在碳酸石灰基粘合剂中的作用


大多数碳酸化反应的特点是产物包裹着未反应的颗粒，导致反应不完全，从而降低材料利用率。这项研究介绍了一种通过部分煅烧石灰石（PCL）制备梯度碳化材料的新方法，该方法在低于完全煅烧温度下进行煅烧，以保持一些原始石灰石，同时部分转化为石灰。研究了机械强度、相演变和微观结构。结果表明，随着 PCL 煅烧程度的增加，材料的力学性能不断提高，孔隙率显着降低，峰值在 35% 左右。然而，过度的煅烧程度阻碍了致密结构的形成。同时，碳酸化过程产生的 CaCO 具有较低的分解温度，表现出两种独特的微观结构特征：未反应的石灰石表面上的封装层和散布在各层之间的微小颗粒 (<5 μm)。这项研究提出了一种有前途的碳酸材料设计方法，证明通过石灰石的受控部分煅烧，为更有效地利用材料开辟了途径。