Chanyotha S, Kranrod C, Chankow N, Kritsananuwat R, Sriploy P, Pangza K
Department of Nuclear Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand.
Radiat Prot Dosimetry. 2012 Nov;152(1-3):71-5. doi: 10.1093/rpd/ncs185. Epub 2012 Aug 19.
The naturally occurring radioactive materials (NORMs) distributed in products, by-products and waste produced from Thai mineral industries were investigated. Samples were analysed for radioactivity concentrations of two principal NORM isotopes: (226)Ra and (228)Ra. The enrichment of NORM was found to occur during the treatment process of some minerals. The highest activity of (226)Ra (7 × 10(7) Bq kg(-1)) was in the scale from tantalum processing. The radium concentration in the discarded by-product material from metal ore dressing was also enriched by 3-10 times. Phosphogypsum, a waste produced from the production of phosphate fertilisers, contained 700 times the level of (226)Ra concentration found in phosphate ore. Hence, these residues were also sources of exposure to workers and the public, which needed to be controlled.
对泰国矿业生产的产品、副产品和废物中分布的天然放射性物质（NORMs）进行了调查。分析了样品中两种主要NORM同位素（226）镭和（228）镭的放射性浓度。发现某些矿物的处理过程中会出现NORM富集现象。钽加工产生的垢中（226）镭的活度最高（7×10⁷贝克勒尔/千克）。金属选矿废弃副产品中的镭浓度也富集了3至10倍。磷肥生产产生的废物磷石膏中（226）镭的浓度是磷矿石中该浓度的700倍。因此，这些残留物也是工人和公众的暴露源，需要加以控制。
