Study On Microwave Sintering And Stability Of Simulated Nuclide Sand

In this paper,the microwave sintering glass curing treatment of uranium tailings beach sand was taken as the core,and Na₂CO₃cosolvent was added to test and evaluate the solid solubility and stability of uranium tailings vitreous with simulated nuclides.The specific content is as follows:Firstly,this paper introduces the harmfulness of uranium tailings pond in detail,and microwave curing method,etc.In addition,the standards and measures for decommissioning uranium tailings pond are summarized.The advantages of microwave glass curing technology in the treatment of uranium tailings beach surface are put forward.Secondly,the dense glass matrix of uranium tailings was successfully prepared by microwave sintering with Na₂CO₃as a sintering aid.Based on the study of microstructure and mechanical properties of sintered solid,the effects of Na₂CO₃additives and sintering temperature were analyzed.XRD results show that the glass can be glassed at 1200?within 30min after adding 20wt.%Na₂CO₃.FTIR analysis shows that the main characteristic peaks of sintered samples are caused by Si-O-Si vibration.Microstructure studies show that the glassy phase is uniformly distributed.The mechanical properties of sintered solids showed that with the increase of Na₂CO₃content and sintering temperature,the highest volume density(2.45±0.01 g/cm³)and Vickers hardness(823±25 HV)were obtained by adding 20 wt.%Na₂CO₃at 1300?and holding for 30min.Finally,the solid solubility and stability of uranium tailings glass-cured radionuclides were studied.A series of solidified radionuclides with different contents were prepared by microwave sintering technology.The solid solution ranges of Ce O₂and Nd₂O₃for uranium tailings glass solidified body are 0wt.%-5 wt.%and 5 wt.%-10 wt.%,respectively.Normalized leaching rate experiments were carried out for the solidified body,and the leaching rates of simulated elements Ce and Nd decreased rapidly first and then slowly with the increase of time.After 42 days,the leaching rates of simulated elements Ce and Nd were both lower than 1×10^-5g.m^-2.d^-1.The results show that the combination of microwave sintering and proper addition of sodium carbonate will provide an effective method to fix the radionuclides in uranium tailings.After a series of tests and analysis,the physical,mechanical and chemical properties of the solidified body of uranium tailings sintered by microwave are stable.