Study On Radioactive Environmental Impact Evaluation Of Rare Earth Tailings And The Construction Of Disposal Technology Evaluation System In China

China has the world’s largest rare earth resources, the processes of rare earth smelting and producing have accumulated a large amount of tailings, which brings the problems of ecological environment destruction and wasting resources. The Chinese government paid great attention on this situation. The distribution of the pollutants and the pollution situation caused by rare earth tailings is still not clear. It is difficult to accurately evaluate the environmental impact of rare earth tailings disposal process, so selecting a typical area and carrying out an environmental impact survey about rare earth tailings disposal technology are urgently needed.In this thesis, the present conditions of the rare earth tailings disposal in our country was investigated, the results show that processes of rare earth ore mining and smelting have produced a large amount of tailings. The tailings piled up take a lot of land resources and their recycling utilization rate is low, which caused the ecological environment pollution and soil erosion.In this thesis, Baotou rare earth industry area, Inner Mongolia, was regarded as a typical investigating area in our country. The environmental impact investigation and technology evaluation on the rare earth tailings disposal technology were done surround Baotou rare earth tailings reservoir and Bayan Obo mining area. The analysis results of environment radiation influence show that the tailings discharged by processes of Baotou rare earth produceing and Bayan Obo mining have lead to the Th pollution in soils. Th in soil surrounding Baotou rare earth tailings reservoir spread mainly by Baotou wind field, the total land area influenced by Th is about87.58km2. Main sources of Th in Bayan Obo mine soils were rare earth tailing heaps, distribution of Th in soils affected by wind, human activities, et al. Analysis on the soil profile indicated that Th in the region’s soil derived from exogenous contribution. Baotou water alpha and beta specific activity results show that the sum of the radioactive level in the surface water and groundwater surrounding Baotou tailings was safe to use as living water.Analytic hierarchy process (ahp) was used to construct the evaluation system of rare earth tailings disposal technology, the expert scoring method was used to determine index weight.Rare earth tailings disposal technology evaluation system is built with technology, pollution emissions, economic benefits and complexity of operation and management, a total of26index layers. Using rare earth tailings disposal technology evalutaion system, Baotou rare earth tailings wet disposal technology status scored47.58, Baotou rare earth tailings dry disposal technology scored47.75. Results indicated that the present status of Baotou rare earth tailings is poor, the reason is that Baotou rare earth tailings wet and dry disposal technology is simply using the liquid seal and dehydration methods for closed or semi-closed tailings, could not efficiently control the spread of the pollutants in tailings in the environment. Tailings disposal technology should be updated as soon as possible, and the corresponding environmental protection measures should be done in existing tailings disposal area to effective control of tailings pollution.