| Rhenium is one of the most scattered metal elements in the world due to its excellent physical-chemical properties.It has been widely used in chemical industry,metallurgy,aerospace and defense advanced scientific fields.Rhenium does not exist as an independent mineral which is usually associated with copper,molybdenum and other metal elements.Meanwhile,rhenium is regarded as one of the most important associated elements in sandstone-type uranium ores as well.By far,the industrial applications of recovering rhenium from uranium minerals has not been seen in the domestic reports.Therefore,the development of separation and the enrichment technology for trace rhenium in solution is a great significance for the recovery of associated rhenium resources in uranium hydrometallurgy process.This paper describes the separation and enrichment of uranium and thorium with a new type of resin synthesized by special anion exchange resin and irradiation grafting method,and the microstructure of resins was characterized by SEM and FT-IR;The adsorption conditions of resins were explored by static adsorption experiment,and the adsorption mechanism was analyzed from the perspective of adsorption kinetics and thermodynamics;The application research of thorium recovery process was carried out with dynamic adsorption-desorption experiments on the column,and the following conclusions were obtained:Through the static adsorption experiment,three anion exchange resins which are LA3100H,D231YT and D314 were selected.Their impacts of solution acidity,contact time,initial concentration and test temperature on the adsorption would be investigated.The results showed that under acidic environment,LA3100H resin has a good adsorption capacity for rhenium,with a saturated adsorption capacity of 129.4 mg·g-1;At p H=1.5,the separation coefficient of rhenium and uranium can reach the maximum,βRe/U=41.68.The adsorption process conforms to the quasi-second-order kinetic model and the Langmuirisothermal model,and is an endothermic,entropy-increasing and spontaneous reaction.The dynamic adsorption-desorption experiment showed that the dynamic saturated adsorption capacity of the resin was 91.98 g·L-1,the saturation-penetration ratio（V）=2.35;After the adsorption was saturated,the resin was desorbed by 1 mol·L-1 NH3·H2O as the desorption reagent,rhenium was completely desorbed by 7 bed volume solutions.Through the static adsorption experiment,the new resins synthesized by the 2-AMPR,Hust-N and Hust-S irradiation grafting methods were selected,and the influences of solution acidity,contact time,initial concentration and test temperature on the adsorption would be investigated.The results showed that the saturated adsorption capacity of rhenium by 2-AMPR resin is 68.8 mg·g-1at p H=3.5;At p H=3.0,the separation coefficient of rhenium and uranium can reach 204.47,which can be used for the recover the associated rhenium resources in the acid uranium mining process.The adsorption process conforms to the quasi-second-order kinetic model and the Langmuir isothermal model,and is an endothermic,entropy-increasing and spontaneous reaction.The dynamic adsorption-desorption experiment showed that the dynamic saturated adsorption capacity of the 2-AMPR resin was 14.28 g·L-1,the saturation-penetration ratio（V）=1.83;After the adsorption was saturated,the resin was desorbed by 1 mol·L-1 NH3·H2O as the desorption reagent,rhenium was completely desorbed by 5 bed volume solutions.In conclusion,this paper confirmed the best conditions for the separation of plutonium and the uranium from LA3100H and 2-AMPR resins through static experimental research on the resin.Moreover,the preliminary dynamic adsorption-desorption test of the resin provided data for further research in the field of the resin expansion test and industrial application.This paper also laid the foundation of the associated plutonium resource recovery technology in the uranium hydrometallurgy process. |
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