Assessment of the radiation exposures during separation of rare earth elements from monazite mineral

Through the separation of rare earths elements REEs from monazite mineral, radiation exposures occur. This study estimated the values of these radiation exposures. The study was occurred through two different treatments of monazite, 10kg of monazite and 10kg of monazite with adding BaCl at the digestion stage. The activity concentration of radon gas varied between 0.81 and 14.4 (Bq/m3) with an average of 8.72 (Bq/m3) while the activity concentration of thoron gas varied between 56.88 and 114.7 (Bq/m3) with an average of 76.14 (Bq/m3). Uranium concentration values in the air of the various areas changed from 0.29 to 0.88 (Bq/m3) with an average of 0.39 (Bq/m3). The gamma equivalent dose rates varied from 0.11 to 0.21 (µSv/h) with average 0.15 (µSv/h). The total annual effective dose received by the workers at the the REES project has values from 0.46 to 12.46 (mSv) with average values of 3.21 (mSv). It was concluded that the values of the occupational effective doses are within the dose limits at the different stages of chemical processing of monazite. However, it is recommended to make technical enhancement to reduce the U-content in the air of the REEs hanger.