Study On Immobilization Method Of Nuclide Uranium In Uranium Tailings Pond

The waste residue produced during the process of uranium mining is usually lime and neutral before entering the tailings reservoir,so that the nuclide is deposited in the alkaline environment without diffusion,and then transported to the tailings storage,At the present the widely used lime alkalization method,although the cost is low,but the effect is poor.Uranium tailings reservoir in the long-term open-air stacking process,uranium prone to acid reflux phenomenon and separate out.In this study,the field investigation and the laboratory simulation research experiment combined to a uranium tailings in Hunan Province as the research object.In particular,the effects of different fixatives on the vertical migration,existence of morphology and precipitation mechanism of nuclides in uranium tailings soils were investigated.The fixation effect of different fixed additives was analyzed by kinetic analysis.And provide reference for radioactive pollution control of uranium tailings in China.The following results are obtained:The effects of immobilized additives on uranium in tailings during acid rain leaching were analyzed by laboratory simulation.The results show: 1)50 days leaching experiments were carried out on the uranium tailings sampled soil by the intermittent semi-dynamic leaching experimental apparatus under the self-made open system.The vertical migration of the uranium precipitation in the tailings soil was not regular,but at 60 ~ 80 cm the precipitation is greatest.The uranium precipitation increased with the depth of the tailings increased,and the total amount of uranium precipitation at different depths is significantly lower than that of the direct leaching tailings soil.2)With lime as a fixed additive,uranium is re-precipitated after day 20,and uranium content increases with time.When lime and ammonium phosphate as immobilization additive,the fixation effect is better than the lime alone effect of the fixed effect,the precipitation concentration has been lower than the tailings of uranium concentration limit(50 ?g / L).According to Fick diffusion theory,the linear regression method is used to kinetic analyze the experimental data and determine the direct leaching of uranium tailings and the mechanism of uranium precipitation by surface elution The leaching mechanism of uranium tailings was covered with lime and ammonium phosphate,the precipitation mechanism was dominated by surface dissolution.