Study on the characteristics of radon exhalation from rocks in coal fire area based on the evolution of pore structure

• Published in: The Science of the total environment Vol. 862; p. 160865
• Main Authors: Li, Pengfei, Sun, Qiang, Geng, Jishi, Jing, Xudong, Tang, Liyun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2023
• Subjects: Air Pollutants, Radioactive - analysis; Construction Materials; Exhalation; Fractal dimension; High temperature; Hot Temperature; Limestone; NMR; Pore structure; Radiation Monitoring; Radon - analysis; Radon exhalation; Limestone; NMR; High temperature; Fractal dimension; Pore structure; Radon exhalation
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.160865

Radon is of great significance as a tracer for the detection of coal fires due to its distinct variations in radon exhalation properties while heating. The research on radon exhalation performance through pore structure is still in its early stages. In this paper, the pore structure and radon exhalation characteristics of heat-treated limestone are studied using indoor tests such as nuclear magnetic and radon measurements. The study's results demonstrate that the radon exhalation rate of limestone initially increases gradually, followed by a steady decline and subsequent increase with the increase in temperature. The radon exhalation rate at 800 °C reaches 2.42 times that at room temperature. The pore structure change within limestone strongly correlates with the radon exhalation rate. The pore volume of micropores (<0.1 μm) plays an essential role in the radon exhalation capacity, which is directly related to the fractal dimension of micropore structure in the heated limestone. The study's findings can be used to identify coal fires. [Display omitted] •Radon exhalation rate of high temperature limestone was studied in detail.•High temperature affects the internal pore structure and radon exhalation.•Microporous structure of limestone affects the exhalation rate of radon.•Radon exhalation rate at 800 °C is 2.42 times higher than that at 25 °C.