@article{
author = "Kuzmanović, Predrag and Filipović Petrović, Leposava and Petrović, Jelena and Forkapić, Sofija and Hansman, Jan and Velimirović, Danijel and Knežević Radić, Jovana",
year = "2024",
abstract = "In the ceramic industry, the quality of the final ceramic tile as well as the possibility of its use depends on the quality and characteristics of the starting raw materials. One of the potential raw materials that can be used in the production of ceramic tiles is kaolinized granite, and it is necessary to examine its characteristics. In this research, the kaolinized granite of the Jadar block, northwestern Serbia, from the Beli Majdan surface mine, Jadranska Lešnica, was examined. Chemical analysis, X-ray diffraction analysis (XRD), and differential thermal analysis (DTA) were carried out. Ignition tests of the prepared composites were also conducted at three selected temperatures (1000, 1100, and 1250°C), where total linear shrinkage and water absorption were determined. The activity concentrations of natural radionuclides and the artificial radionuclide 137Cs were determined using the gamma spectrometry method, and then the radiation risk for the external exposure of workers when working with this raw material was assessed. For the samples with the highest content of 226Ra, radon exhalation measurements were performed with the RAD7 device, and the values of the radon emanation coefficient were determined, as well as the values of alpha dose equivalents, which quantified the potential internal exposure of workers. The results of the chemical analysis showed that the content of Al2O3 in the examined composites ranged from 19.11-21.00%, and the content of Fe2O3 from 1.53-1.72%. Additionally, the K2O content in the tested composites ranges from 4.01-5.46%, which indicates the presence of K-feldspar and muscovite, and the Na2O content from 1.82-2.61%. Based on XRD analysis, it was established that the mineral composition of kaolinized granite includes quartz, feldspar, mica, calcite/dolomite, and kaolinite minerals. DTA analysis indicates the occurrence of minor endothermic processes at 488.05°C and 558.12°C, as well as an exothermic process at 980.8°C. The color of the ignition is brick red to dark brown red. A trend of increasing linear shrinkage and decreasing water absorption with increasing ignition temperature was observed with the normal appearance of the samples. The average activity concentration of natural radionuclides are around and below the average values for building materials, expect for 40K. The values for 137Cs are below the values measured in soil. Annual effective doses estimated for external exposure are below 1 mSv y-1, which indicates that there is no increased radiation risk when working with this raw material. The values of the radon mass exhalation rate are in the range of 61-113 mBq kg-1 h-1, and the values of the radon emanation coefficient are 6.3-8.4%. The average value of the alpha dose equivalent is 1mSvy-1, which indicates a potential exposure to radon below 100 Bq m-3. Based on the obtained results, it can be concluded that kaolinized granite is a high-quality and radiologically safe raw material for making ceramic composites in the production of ceramic tiles. It has all the necessary characteristics to partially or completely replace feldspar in ceramic composites.",
publisher = "Elsevier",
journal = "Radiation Physics and Chemistry",
title = "Physico-chemical, technological and radiological characteristics of kaolinized granite from Northwestern Serbia",
number = "111885",
volume = "222",
doi = "10.1016/j.radphyschem.2024.111885"
}
