Curing process method for radioactive nuclide polluted sandy soil

Abstract

The invention provides a curing process method for radioactive nuclide polluted sandy soil, which comprises the steps of thermite preparation and curing process. Aluminum powder, ferric oxide powder and auxiliaries 1 are weighed by mass ratio of 0.33-0.66:1.00-2.00:0.01-0.30 and sequentially placed in a blender mixer to be stirred for 30-60 minutes at the speed of 60-120 r/min under the normal temperature and the constant pressure till the mixing is even. The curing process comprises the steps of mixing, dumping and embedding, ignition and post-processing. The mixing step is that the sandy soil with grain size smaller than 1cm and with SiO2 as a main component, thermite, auxiliaries 2 and simulate radioactive nuclide are mixed by mass ratio of 1.0:1.6-3.0-0.01-0.35:0.01-0.20 and stirred for 90-120 minutes at the speed of 45-60 r/min under the normal temperature and the constant pressure till the mixing is even. The dumping and embedding step is that a mixture obtained in the mixing step are dumped and embedded in a steel container or a cement pool with a cover plate and a gas filtering device at the top, dry sand with the depth of 15-50cm is dumped and embedded around the mixture, and dry sand with the depth of 50-100cm is covered on the mixture and then covered by the cover. The ignition step is that an ignition device is installed at the upper portion or the lower portion of the mixture, is powered on to perform ignition and is powered off to measure resistance and confirm the igniting effect. The post-processing step is that a cured body is taken out or embedded on the spot when cools to the environmental temperature.

Description

technical field [0001] The invention relates to the treatment of radioactive waste, especially for the sandy soil polluted by radionuclides, and the solidification treatment method adopted has important application value. Background technique [0002] At present, the solidification technology of radioactive waste, especially high-level radioactive waste, is mainly vitrification and artificial rock solidification. These two solidification methods use an external heating source to heat the waste and additives to a molten state, and then cool them to form a glass or ceramic body. Heating and melting radioactive waste to form low-melting glass requires a temperature of 800°C, while artificial rock must reach 1300°C-1500°C for solidification. produce secondary pollution. Self-propagating high-temperature synthesis is a new technology that uses the self-exothermic chemical reaction to continue the reaction and finally synthesize the desired material or product. It can be applie...

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Problems solved by technology

[0003] Literature retrieval disclosure: 1. Lu Xin et al. published the article "Self-propagating high-temperature synthesis of fixed radioactive waste" in 2003, 31 (2): 205-208, "Journal of Silicates", using chromium trioxide, titanium powder, oxidation Calcium and titanium dioxide were used as raw materials, and a calcium titanate solidified body was synthesized by a self-propagating high-temperature synthesis quasi-isostatic reactor device, which was used to fix the nuclide Sr; ② Zhang Ruizhu et al. The article "Self-propagating high-temperature synthesis of perovskite-type artificial rock solidified body" published in the Journal of University of Science and Technology revealed that the self-propagating high-temperature synthesis quasi-isostatic reactor device can handle a small amount of high-level radioactive waste after sorting and purification, but The batch size is small, the cost is too high, it is not suitable for large-scale engineering applications, and it is not realistic to deal with a large amount of soil that is difficult to sort and clean

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