Kljajević Ljiljana, Nenadović Miloš, Ivanović Marija, Bučevac Dušan, Mirković Miljana, Mladenović Nikolić Nataša, Nenadović Snežana
Department of Materials, "Vinča" Institute of Nuclear Sciences-National Institute of the Republic of Serbia, University of Belgrade, Mike Petrovića Alasa 12-14, 11000 Belgrade, Serbia.
Department of Atomic Physics, "Vinča" Institute of Nuclear Sciences-National Institute of the Republic of Serbia, University of Belgrade, Mike Petrovića Alasa 12-14, 11000 Belgrade, Serbia.
Gels. 2022 May 26;8(6):333. doi: 10.3390/gels8060333.
In this paper, raw natural metakaolin (MK, Serbia) clay was used as a starting material for the synthesis of geopolymers for thermal treatment. Metakaolin was obtained by calcination of kaolin at 750 °C for 1 h while geopolymer samples were calcined at 900 °C, which is the key transition temperature. Metakaolin was activated by a solution of NaOH of various concentrations and sodium silicate. During the controlled heat treatment, the geopolymer samples began to melt slightly and coagulate locally. The high-temperature exposure of geopolymer samples (900 °C) caused a significant reduction in oxygen, and even more sodium, which led to the formation of a complex porous structure. As the concentration of NaOH (6 mol dm and 8 mol dm) increased, new semi-crystalline phases of nepheline and sanidine were formed. Thermal properties were increasingly used to better understand and improve the properties of geopolymers at high temperatures. Temperature changes were monitored by simultaneous use of thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The loss of mass of the investigated samples at 900 °C was in the range of 8-16%. Thermal treatment of geopolymers at 900 °C did not have much effect on the change in compressive strength of investigated samples. The results of thermal treatment of geopolymers at 900 °C showed that this is approximately the temperature at which the structure of the geopolymer turns into a ceramic-like structure. All investigated properties of the geopolymers are closely connected to the precursors and the constituents of the geopolymers.
在本文中，天然偏高岭土（MK，塞尔维亚）原土被用作合成用于热处理的地质聚合物的起始原料。偏高岭土是通过将高岭土在750℃下煅烧1小时获得的，而地质聚合物样品在900℃下煅烧，这是关键的转变温度。偏高岭土由不同浓度的NaOH溶液和硅酸钠活化。在受控热处理过程中，地质聚合物样品开始轻微熔化并局部凝结。地质聚合物样品在900℃下的高温暴露导致氧气显著减少，甚至钠含量减少更多，这导致形成复杂的多孔结构。随着NaOH浓度（6 mol dm和8 mol dm）的增加，形成了霞石和透长石的新半晶相。热性能越来越多地被用于更好地理解和改善地质聚合物在高温下的性能。通过同时使用热重分析（TGA）和差示热分析（DTA）来监测温度变化。所研究样品在900℃下的质量损失在8 - 16%范围内。地质聚合物在900℃下的热处理对所研究样品的抗压强度变化影响不大。地质聚合物在900℃下的热处理结果表明，这大约是地质聚合物结构转变为类陶瓷结构的温度。地质聚合物的所有研究性能都与地质聚合物的前驱体和成分密切相关。
