以承德铁矿矿集区不同类型的典型代表性铁矿原矿石、磁选尾矿、废石为对象进行放射性水平研究,研究发现承德地区各类型铁矿典型矿区铁矿石、尾矿、废石中238 U含量最大分别达到 320 Bq∕kg、290 Bq∕kg、390 Bq∕kg,为接触交代型矿区;232 Th含量最大分别达到 130 Bq∕kg、143 Bq∕kg、54 Bq∕kg;226 Ra含量最大分别达到 97 Bq∕kg、80 Bq∕kg、45 Bq∕kg,为沉积变质型矿区、接触交代型矿区;铀(钍)系单个核素活度浓度均小于 1000 Bq∕kg,建议可简化建设项目环境影响评价管理要求,豁免该地区铁矿开采、磁选项目环境影响评价书(表)开展铀(钍)系单个核素活度浓度检测.该地区铁矿石加工过程中的废石、尾砂放射性活度发生富集效应,产生的核素水平要大于原始伴生放射性矿.
In this paper,raw ore,magnetic separation tailings and waste rock of the typical mines of different types of iron ore in Chengde iron ore concentration area are selected as objects to research the radioactivity level.It is found that the maximum 238U content of iron ore,tailings and waste rock in the typical mining areas of various types of iron ore in Chengde area reaches 320 Bq∕kg,290 Bq∕kg and 390 Bq∕kg respectively,which are contact metasomatic mining areas.The maximum 232Th content is 130 Bq∕kg,143 Bq∕kg and 54 Bq∕kg respectively.The maximum content of 226Ra reaches 97 Bq∕kg,80 Bq∕kg and 45 Bq∕kg respectively,which are depositional metamorphic mining area and contact metasomatic mining area.The activity concentration of single uranium(thorium)series nuclide is less than 1 000 Bq∕kg.It is suggested that the environmental impact assessment management requirements of construction projects can be simplified,and the detection of single uranium(thorium)series nuclide activity concentration can be exempted from the environmental impact assessment(table)of iron mining and magnetic separation projects in this area.In the process of iron ore processing in this area,the radioactive activity of waste rock and tailings is enriched,and the level of nuclide produced is higher than that of the original associated radioactive ore.