Innovative separation of Caesium and Strontium using flotation and magnetic particles, to convert large waste volumes into small waste packages

英国和韩国政府都有一项战略，以维持(在英国)或提高(在韩国，计划到2022年增加59%的装机容量)核能发电水平，以提供“低碳”能源。这两个国家拥有悠久而成熟的民用核工业；生产需要管理的遗产地和材料。鉴于新建造的反应堆和遗留废物的需要，显然必须制定废物管理和退役的创新办法，以安全和具有成本效益的办法解决储存和处置问题。放射性流出物的处理是几乎所有核设施面临的共同但具有挑战性的任务之一，无论是现役工厂还是退役地点。从冷却池到燃料后处理的各种液体需要立即处理，以减少安全排放的活动。虽然正在进行的工厂运行中的低效率去除路线可能导致陆地和海洋中的长期环境积累，但可移动放射性离子的突然释放可能会导致严重的环境污染。福岛等重大核事故后处理大量污水的严重困难，突显了对新的灵活技术的要求。铯-137(~(137)Cs)和锶-90(~(90)Sr)的释放由于其高的裂变产额和显著的半衰期(t1/2~29年)而引起了极大的安全和环境关注。一旦被释放到生物圈，裂变产物很有可能经历一系列化学和地球化学过程，最终影响人类健康。协助补救的方法面临着重大的科学和工程挑战，这些挑战涉及：i)裂变产物与环境之间复杂的相互作用；ii)处理大量废物的要求。在这个英国-韩国项目中，将研究一种基于双泡浮选和磁选的新概念来处理放射性(Cs和Sr)污染的环境。三阶段流程：I)Cs+和Sr2+吸附，II)异相气泡成核和浮选，III)磁选和体积减小将串联进行，将大容量的垃圾转化为适合临时储存的小垃圾包。基于表面润湿性的浮选方法因其通用性和对处理大量废物的适用性而被选为最合适的修复方法。与水力空化相结合，该工艺将能够将受污染的颗粒(细粘土和磁性载体)从不需要的煤矸石中分离出来，产生泡沫，可以通过应用磁场控制泡沫失稳的速度进一步处理，但也可以控制废物包装的总体积，这一点非常重要。这项研究将为开发革命性的技术来处理环境污染的土地(水和土壤)奠定科学基础。科学/工程办法有可能在全球退役方案和修复遗留核设施方面向前迈出技术一步，从而使核电的足迹不会对环境产生长期影响。

Both the UK and Republic of Korea governments have a strategy to maintain (in the UK) or increase (in the ROK where capacity is planned to increase by 59% by 2022) the level of nuclear power generation in order to provide "low-carbon" energy. The two countries have a long and established civil nuclear industry; producing legacy sites and materials which will need to be managed. There is a clear imperative, given the needs of both new build reactors and legacy wastes, to develop innovative approaches to waste management and decommissioning for safe and cost effective answers to storage and disposal issues. The treatment of radioactive effluent streams is one of the common yet challenging tasks facing almost all nuclear facilities, whether active plants or decommissioning sites. Various liquid streams from cooling ponds to fuel reprocessing require immediate processing to reduce the activity for safe discharge. While low efficiency removal routes in on-going plant operations can lead to long term environmental accumulation in land and sea, the sudden release of mobile radioactive ions can lead to severe environmental contamination. The acute difficulties of treating large volumes of effluent following major nuclear incidents such as Fukushima, highlights the requirements for new flexible technology. The release of cesium-137 (137Cs) and strontium-90 (90Sr) in particular pose substantial safety and environmental concern due to their high fission yield and significant half-lives (t1/2 ~ 29 years). Once released into the biosphere there is a high potential for the fission products to undergo a series of chemical and geochemical processes that ultimately impact human health. Methods to assist in remediation face substantial scientific and engineering challenges associated with: i) complex interactions between the fission products and the environment, and ii) the requirement to process large volumes of waste. In this UK-Republic of Korea project, a new concept based on dual-bubble flotation and magnetic separation will be studied to treat radioactively (Cs and Sr) contaminated environments. The 3-stage process: i) Cs+ and Sr2+ adsorption, ii) heterogeneous-bubble nucleation and flotation, and iii) magnetic separation and volume reduction will proceed in series to transform large waste volumes into small waste packages suitable for interim storage. Surface wettability-based flotation is chosen as the most appropriate method for remediation due to its versatility and applicability for processing large waste volumes. In combination with hydrodynamic cavitation, the process will be capable of separating contaminated particles (fine clays and magnetic carriers) from the unwanted gangue to produce a froth that can be further treated by applying a magnetic field to control the rate of froth destabilization, but also and quite importantly control the overall volume of the waste package. The research will lay scientific foundation for developing revolutionary technology to treat environmentally contaminated land (aqueous and soils). The scientific/engineering approach has the potential to develop a technological step-forward for global decommissioning programmes and the remediation of legacy nuclear sites, such that the footprint of nuclear power has no long lasting impact on the environment.