Climate change is such an urgent problem that despite the difficulties with radioactive waste, nuclear power is once again in high demand. At least until the moment when renewable energy sources, such as solar or wind, will be more widely used. The world ocean is a good source of enriched uranium, but uranium is stored on its bottom in such small quantities that its extraction is economically unprofitable. Nevertheless, scientists at their Stanford University (USA) have developed a new method that can triple the volume of uranium mining. This means that we can get a new source of uranium, which will allow us to control the level of carbon dioxide in the atmosphere.
A surprisingly large amount of uranium is in the ocean in the form of positively charged uranyl ions. Its total quantity is about 4.5 billion tons, which is enough to feed all existing plants for about six millennia in advance. However, until now, mining of uranium was too expensive and took a lot of time.
The best way to get uranium from seawater is to dip into it polymer fibers coated with an organic chemical amidoxime. The uranyl ions are attached to the amidoxime, and later can be extracted and processed into uranium fuel. The key questions to the effectiveness of this method are the following: how quickly the ions attach to the amidoxime, how many ions will attach and how many times the polymer fibers can be used again.
A team of Stanford scientists came up with a conductive hybrid of carbon fiber and amixodymium. It is able to absorb nine times more uranium than the previous models of fiber. During the 11-hour test, the team managed to extract three times more uranium, and the hybrid of carbon fiber and amixodyma served three times longer than usual amixodyma.
In 2012, Japan estimated that using a conventional uranium mining method, its price would be $ 300 per kilogram. This is about three times the commercial value, but right now the price has almost halved. “We still have a lot of work, but these are big steps towards practicality,” said co-author Li Cui.