Huang Ju, Liu Zanqun, Cui Yu, Yuan Qiang, Deng Dehua
School of Civil Engineering, Central South University Changsha Hunan 410075 China
RSC Adv. 2024 Apr 9;14(16):11358-11367. doi: 10.1039/d4ra01341g. eCollection 2024 Apr 3.
Half-calcined dolomites (HCDs) have been widely used in environmental remediation, medicine, and construction. However, advanced calcination technologies are required to modify their microstructure and thus improve their working performance. Herein, we investigated the effects of a variety of inorganic salts on the decomposition of dolomite based on thermogravimetric, compositional, and morphological analysis. The thermogravimetric data showed that certain salts significantly lowered the half-decomposition temperature of dolomite, which included LiCl, CaCl, MgCl, AlCl, LiNO, KNO, KCO, LiCO, LiSO, NaPO, and KPO. Compositional analysis demonstrated that only half-decomposition occurred when salt-bearing dolomite was calcined at a temperature of 723-923 K, leading to the formation of CaO-free HCDs composed of periclase and Mg-calcite having a Mg level of 2.0-10.5 mol%. Morphological analysis showed that porous HCDs were feasibly obtained by calcining salt-bearing dolomite at 723-923 K. MgO coarsening occurred at a temperature above 873 K, but it could be avoided by controlling the calcination time. The mechanism of salts may be related to the heterovalent doping effect, which may lead to an increase in the concentration of vacancies in the dolomite lattice.
半煅烧白云石（HCDs）已广泛应用于环境修复、医学和建筑领域。然而，需要先进的煅烧技术来改变其微观结构，从而提高其工作性能。在此，我们基于热重、成分和形态分析，研究了多种无机盐对白云石分解的影响。热重数据表明，某些盐显著降低了白云石的半分解温度，这些盐包括LiCl、CaCl、MgCl、AlCl、LiNO、KNO、KCO、LiCO、LiSO、NaPO和KPO。成分分析表明，含盐水白云石在723-923K温度下煅烧时仅发生半分解，导致形成由方镁石和Mg含量为2.0-10.5mol%的Mg-方解石组成的无CaO的HCDs。形态分析表明，通过在723-923K温度下煅烧含盐水白云石可获得多孔HCDs。在高于873K的温度下会发生MgO粗化，但可通过控制煅烧时间来避免。盐的作用机制可能与异价掺杂效应有关，这可能导致白云石晶格中空位浓度增加。
