The industry devoted to the production of phosphoric acid by using as raw material sedimentary phosphate rock (PR) is considered as a NORM activity (Naturally Occurring Radioactive Materials), due to the high levels of U-series radionuclides contained in this ore, which are 1-2 orders of magnitude higher than those in unperturbed soils. This fact allowed us to develop a deep characterization of the raw materials, wastes, main intermediate materials, and final products obtained at a typical phosphoric acid factory. The elemental composition (major, minor and trace elements), radionuclide concentrations, grain size distribution, mineralogy and micro-structural composition were analyzed. The aim of this characterization was to obtain information for operators and maintenance personnel involved in clean-up and waste management operations. The highest concentrations of some heavy metals and radionuclide activity concentrations were found in the "scales" (or internal incrustations)from the pipes that carry either phosphoric acid (PA) or the phosphogypsum waste (PG). The highest concentrations where found for 226Ra and 40K,with values up to 9 and 5 Bq g-1, respectively. In addition, high concentrations of many toxic heavy metals and trace elements, such as Cd, Cr, Ni, Sr, Y, V, Zn, Th, and U, were found in some sludge samples. The shielding effect of the containers/vessels/pipes has an essential role in the measured external dose in the intermediate products. The radiological implications of natural radionuclides with higher activity showed that if the maximum particulate matter concentration established in the Spanish regulation is verified, and taking into account the most conservative scenario, the annual limit of 1 mSv y-1 is not exceeded.

中文翻译：

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对磷酸生产厂的材料进行放射和理化表征，以评估工人的放射风险。

由于矿石中所含的U系列放射性核素含量很高，因此致力于将磷酸沉淀岩（PR）用作原料生产磷酸的行业被视为NORM活性（天然放射性物质）。比未受干扰的土壤高1-2个数量级。这一事实使我们能够对典型的磷酸工厂获得的原材料，废物，主要中间材料和最终产品进行深入的表征。分析了元素组成（主要，次要和痕量元素），放射性核素浓度，晶粒尺寸分布，矿物学和微观结构组成。此特征的目的是为参与清理和废物管理操作的操作员和维护人员获取信息。在载有磷酸（PA）或磷石膏废料（PG）的管道的“水垢”（或内部结垢）中发现了一些重金属和放射性核素活性最高的浓度。最高浓度为226Ra和40K，分别高达9和5 Bq g-1。此外，在一些污泥样品中还发现了高浓度的许多有毒重金属和微量元素，例如Cd，Cr，Ni，Sr，Y，V，Zn，Th和U。容器/容器/管道的屏蔽作用在中间产品的外部剂量测量中起着至关重要的作用。具有较高活性的天然放射性核素的放射学意义表明，如果西班牙法规中规定的最大颗粒物浓度得到验证，