Airborne Radioactive Pollution Research On Rare Earth Mining In The Region Of Panxi

Rare earth mine is one of the associated radioactive minerals, In addition to containing the necessary elements outside of rare earth mining, At the same time, associated with higher levels of the mineral resources of natural radioactive substances.Scale to measure the production of rare earth industry that is a large industry on environmental pollution in China. Because there is no feature for the rare earth industry standards for pollutants discharge and rare earth emissions of industrial enterprises management and environmental impact assessment of construction projects, design and completion of the acceptance and so on.Has been implementing an integrated class emission standards it is In the application of rare earth industry is gradually show less.With the rapid development of China's rare earth industry, the rare earth mine and production plant is fairly well distributed throughout the country.Because the emission characteristics of the production of pollutants such as ammonia, thorium dust and other dust can not be effectively controlled, therefore, needed according to the inherent characteristics of rare earth industry to apply to the emission standards of the industry.At the present, rare earth emissions of industrial enterprises management and environmental impact assessment of construction projects, design and completion of the acceptance, only reference to the above and non-ferrous metal industry-related pollutants emission standards.But with the rapid development of China's rare earth industry and the rare earth mine and production plant is fairly well distributed throughout the country.So the production of pollution control there are some problems, more serious environmental pollution, especially the environmental quality requirements in the case of the increasingly stringent, universal lack of specific pollution control standards.In the application of rare earth industry is gradually show less. Therefore, according to the inherent characteristics of rare earth industry, development apply to this industry the《Rare earth industry emission standards》is very urgent and necessary.This paper is to Sichuan "rare earth industry, industrial pollution discharge standards of" sub-project on "rare earth production of radioactive pollution and the emission limits" relying on such projects undertaken. The rare earth minerals in Panxi area in Sichuan Mianning County as study referent. To study Enterprises generated airborne waste as the core of. By CIF-3000F that is low backgroundγspectrometry analysis of radionuclides measured in which content and specific activity, then estimate the atmospheric dispersion model introduced in the waste gas containing thorium radionuclide emission limits.Root with the public health risk assessment method of assessing degree of harm to human body. Finally, mine last for many enterprises of a situation to optimize the emission limits for planning and application life cycle assessment methods to control rare earth industry "three wastes" pollution.By rare earth mining enterprises in Panxi typical sampling, measurement, analysis concludes:1. Fluorocarbon rare earth ore miners at the Panxi in Sichuan that is the second largest bastnaesite in China. That reserves of 1 million tons, accounting for 1.02% of proved reserves and have the large, the high grade and easy to pollution of those toxic, hazardous characteristics of low impurity content. Ore in the natural radionuclides of natural thorium-based.2. Rare-earth ore mining to produce the airborne main sources of radioactive waste in Panxi: Dust generated by mining, dust,and concentrate produced by smelting mixed with HCl and CO₂ gas, Wet separation with the emission of HCl, ammonia and organic extractant and boilers burning coal emissions containing SO₂, smoke dust. Dust containing thorium has led to 0+ of the trend of pneumoconiosis.3. Typical rare earth mine in Panxi radioactive dust in the air data, the results show that only the dose caused by inhalation of the 232Th, and the 232Th is continue decaying. It's a series of daughter nuclides in radiation hazards can not be ignored. Therefore, controlling the emissions of dust containing thorium should be strict limits to the general particulate matter. If it is determined the existing enterprises with thorium dust emission concentration limit of 20mg/m³, new enterprises with thorium dust emission concentration limit of 15mg/m³ is appropriate.4. Health risk assessment is an internationally developed 80s of the 20th century a new research field: The use of uniform hazard indicators, quantitative description of various pollutants (such as radioactive pollutants, chemical carcinogens and non-carcinogenic pollutants) on the risk of harm to human health. According to this evaluation model, calculated on the week of airborne radioactive materials within 80 km radius of the public resulting normalized collective effective dose, and normalized health risks were 1.19×10² bodies·Sv/a and 8.69 bodies·Sv/a. Due to certain conditions, this article Panxi get airborne emissions of rare earth ore due to the size of the public health risk is only in rare earth mining of radioactive dust in the Th was calculated and obtained, not consider the different levels of other harmful substances, the distribution of the population in recent and relevant information, uncertainty and other factors. Therefore, this paper derived the value of the 8.7 bodies·Sv /a is the only rare earth mine Panxi airborne emissions endanger public health due to a preliminary estimate. It can be that rare earth ore by the airborne hazards to public health caused by emissions of about 10 bodies·Sv / a.5. The life cycle assessment (LCA) for pollution prevention measures in the decision making process of environmental impact throughout the system to provide information helpful in choosing the ideal of pollution prevention.6. Specified for the radioactive waste management: every practice or facility should determine the limit emissions to the environment. Determine emission limits should be the optimization analysis, at the same time as leaving room for future development.Considering only the radiation safety, emission limits to meet the dose constraint value and optimization required results, the dose to critical population group should not exceed the value of the corresponding dose constraint.At the same time, this view of the current status of rare earth ores, and radioactive pollution indiscriminate exploitation of more and more serious, put forward some suggestions are:1. Strengthen supervision and management of rare-earth ore. Environmental protection departments at all levels of radiation to the environment of rare earth mine management into their work schedule, Strict enforcement and implementation of the《People's Republic of Radioactive Pollution Control Act》. Full use of existing pollution control facilities, play its role in pollution prevention and control of radioactive rare earth ore.2. Scientific planning and rational set the mineral rights and the exploitation of scientific method. Relevant departments at all levels, according to rare earth in Mining Maoniuping in Mianning the actual situation, on the rare earth mining and mine to make a scientific plan, and submit the provincial environmental protection department approval.Recommended the rare earth in Mianning County Maoniuping and the amount of resources approved by the state mining in total. Reasonable to set the mining right to alter the existing mining area "small, scattered, rotten" the status to save rare earth resources and to achieve sound and rapid development.To scientific proof and reasonable implementation of rare earth mining method is difficult to restore the ecological, heavy metals and radioactive substances exposed serious regional, to consider changes,"stripping"to"hole" between ecological destruction and the prevention of water pollution.3. Environmental awareness and actively implement environmental management systems in time to re-submit the environmental impact assessment approval process. The "three simultaneous" acceptance procedures, prevention and control of radioactive pollution of their explicit requirements. On the mining of ore, ore and tailings in the selection of the radionuclide content of the necessary follow-up analysis, understanding and knowledge of rare earth mine in the change of radionuclides. To urge enterprises to prevent pollution.4. Sound rules and regulations, strict internal management. Should strictly require the disposal of mine tailings enterprise examination and approval system, pollution control facilities, operation and management system. Strengthen the management of tailings should be kept dam, without the management agreement, not to exceed the national requirements of radionuclide content in the tailings material for civilian use.5. Mining and production process control of air pollution. Most of all-mechanized mining of rare earth mining, a large number of processes in the open pit mining operations such as wet, so as to effectively control the amount of dust generated. Most of the production process for the wet concentration plant operations and laboratory operations, less dust production points, there is no organized emission sources. Outdoor loading and unloading, transportation, broken, etc. The dust generated in the process, an unorganized emission source, by spray, water spray dust suppression measures.