Analysis of cement raw materials radioactivity in Chongqing

Under the guidance of national energy-saving and environmental protection policies, the addition of high-radioactivity waste materials to cement may lead to the accumulation of various radioactive elements, potentially harming human health if not properly controlled. This study selected three representative cement production companies in Chongqing for sampling based on their production line processes. The activities of the radionuclides ²²⁶Ra, ²³²Th, and ⁴⁰K in raw materials, fuels, additives, and final products were measured using a low-background high-purity germanium spectrometer. Additionally, the internal and external exposure indices, radium equivalent activity, and annual effective dose were calculated. A curve illustrating the changes in radioactivity was put forward, and the variations in radioactivity during the process from raw materials to final products were analyzed. The main reasons for the changes in radioactivity during cement production were found to be the proportion of raw materials, the addition of high-radioactivity additives, and the accumulation from kiln calcination processes. Based on these findings, recommendations for controlling radioactivity during cement production were provided.