钢铁冶炼的放射性排放及其辐射安全监管

中国钢铁行业发展迅速,2014年的粗钢产量已达到世界总量的49.5%。钢铁冶炼的原料包括铁矿石、煤、石灰石等,均含有天然放射性核素(U系、Th系、40 K等)。在烧结、焦化、高炉炼铁和转炉炼钢的高温冶炼过程中,~(238)U的子体~(210)Po和~(210)Pb达到熔点和沸点后挥发,扩散吸附到大气颗粒物上随其他气态污染物排放,增加了公众照射剂量。本文阐述了德国、意大利、英国、荷兰、澳大利亚、埃及等国、欧盟和IAEA等国际组织对钢铁冶炼中天然放射性排放的研究进展,发现烧结和炼铁是天然放射性排放的两个主要工艺,部分国家和组织制定了针对天然放射性物质照射的审管政策。烟囱烟气中~(222)Rn、~(210)Pb、~(210)Po的测量方法和辐射影响评价需进行深入研究。

Radiological Emissions and Radiation Safety Supervision of Iron and Steel Production

Iron and steel industry in China developed fast with a crude steel production of 49.5% in the world in 2014. The raw materials used in iron and steel production are iron ore, coal and limestone, which all contain low levels of naturally occurring radioactive materials (NORM) in the U and Th decay chains and ⁴⁰K. Due to high temperature in the process of sintering, coking, iron and steel making, ²¹⁰Pb and ²¹⁰Po in ²³⁸U series volatile after reaching their melting points and boiling points, and then condense on the atmospheric particles and release with other air pollutants so as to increase the public exposure. This paper demonstrated the recent research progress of NORM emissions from iron and steel making in Germany, Italy, the United Kingdom, the Netherlands, Australia and Egypt, as well as the reports from European Commission and IAEA. Sintering and iron making are the main processes that release naturally occurring radioactive materials. Some countries and organizations have developed management policies on NORM radiation. Measurements and radiological impact assessment of ²²²Rn, ²¹⁰Pb and ²¹⁰Po in stack effluents should be intensively studied.