中国海水提铀研究进展

Research advances on extracting uranium from seawater in China

铀资源是核工业赖以发展的基础资源,是国家核能发展的战略资源,是实现核电可持续发展的重要因素.随着陆地铀矿资源的日益匮乏,开发非常规铀资源势在必行.海水提铀是最有潜力、最切实可行地获取大量铀资源的途径.但是海水提铀面临着海水中铀浓度极低(3.3μg/L)、多种共存离子浓度远高于铀酰离子等严峻的挑战,因此寻找高效率、高选择性的提铀方法成为解决问题的关键.海水提铀作为一项综合性极强的应用研究项目,近年来受到了全世界科学家的关注.本文从各类吸附材料及其吸附机理等方面介绍了近年来中国海水提铀的研究进展,并结合我国海水提铀研究的发展现状对未来的研究方向进行了展望.

Uranium resource is the basic resources for the development of nuclear industry and strategic resources for the development of nuclear energy, which is also an important factor to realize the sustainable development of nuclear power. More than 1000× uranium resource exists in seawater than in terrestrial ores. With the demand on nuclear electricity increasing in the coming decades, extracting uranium from seawater is the most promising and feasible solution to the shortage of conventional uranium resources. Extracting uranium from seawater, as a comprehensive and practical event, meet several great challenges. Firstly, the uranyl ions concentration in seawater is ultralow （3.3 μg/L）, and the concentration of coexisting ions is much higher than uranyl ions. Secondly, the high salinity or ionic strength, the temperature and the specific pH value in seawater is usually stable. Thirdly, biofouling and flowing water may influence the physical and chemical properties of the adsorbents, which also reduces the reusing rate of the adsorbents. So the core of research on extracting uranium from seawater is searching and preparation for adsorbents with high efficiency, selectivity, durability and reusa- bility. The adsorbents contains inorganic adsorbents and polymeric adsorbents. Inorganic adsorbents like metal oxides and MOFs, perform high surface area and adsorption rate in low pH value, but cannot be widely used in real seawater. Polymeric adsorbents like poly（amidoxime） is widely used in recent researches, they perform well in selectivity, adsorption capacity and durability. Polymeric adsorbents are mainly prepared by radiation-induced graft polymerization （RIGP） and atom transfer radical polymerization （ATRP）. In this paper, the research advances on extracting uranium from sea- water in China is introduced on uranium adsorbents, adsorption mechanism and marine tests. Although extracting uranium from seawater is widely paid attention to since 1960s, there are still countless problems to solve. Firstly, the mechanism research on extracting uranium from seawater is usually simplified because there are too many complex factors in seawater. Secondly, the current preparation methods are still much too complicated, so the ma- terials＇ costs are still very high. Thirdly, there is no specific standard for the evaluation of the adsorbents, which is bad for the optimization of uranium adsorbents. Fourthly, the marine environment factors, like seawater temperature and seawater velocity, may influence the adsorption process. Finally, the engineering of marine tests needs more experience to reduce the cost and improve the efficiency. Only by solving the above problems, can the goal of extracting uranium from seawater be achieved. Firstly, establish a database to improve the depth and systematic of theoretical research, so that we can grasp the methods to design a new adsorbent with high properties. Secondly, introduce new preparation methods, new device and new materials to the extracting uranium from seawater area. Thirdly, build a public testing platform and develop standardized methods to evaluate the performance of the uranium adsorbents. Fourthly, investigate the influence of marine environment factors on adsorbents performance in real seawater. Finally, attempt more marine tests for the optimization of the adsorbents and extracting devices to reduce the costs. So that the engineering of extracting uranium from seawater can finally achieved in the future.