Nanoparticle manufacturing device and nanoparticle manufacturing method and method of manufacturing nanoparticle-dispersed liquid alkali metal

Abstract

A nanoparticle manufacturing device capable of particle size control of nanoparticles made of a raw material metal powder and control of the occurrence condition of chaining of nanoparticles and of necking. The device 1 is provided for manufacturing nanoparticles by heating and melting a mixture of a raw material metal powder and a carrier gas in a heating space, cooling the mixture in a cooling space and collecting the mixture in a collection space. The heating space, the cooling space and the collection space form a continuous flow path without a back flow, and the cross-sectional area of the collection space is set at a large value compared to the cross-sectional area of the heating space and the cooling space. Further, there is provided a method of manufacturing a nanoparticle-dispersed liquid alkali metal by dispersing nanoparticles in a liquid alkali metal. A liquid alkali metal obtained by dispersing nanoparticles in the liquid alkali metal is manufactured by performing a rough dispersion step of stirring nanoparticles in the liquid alkali metal by a physical effect and a dispersion step of dispersing nanoparticles in the liquid alkali metal by irradiating the liquid alkali metal with ultrasonic waves after the rough dispersion step.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to. (A) a nanoparticle manufacturing device and a nanoparticle manufacturing method which are suitable for manufacturing nanoparticles of single metals, alloys and the like.[0003]Further, the present invention relates to (B) a method of manufacturing a nanoparticle-dispersed liquid alkali metal which is used to manufacture a liquid metal obtained by uniformly dispersing nanoparticles in a liquid alkali metal, such as reactor-cooling liquid sodium.[0004]2. Description of the Related Art[0005]Regarding (A) described above, particles having sizes of the order of nanometers, what is called nanoparticles, have unique properties which manifest themselves due to the size effect or have a large specific surface area and, therefore, in recent years studies aimed at applying nanoparticles have been carried out actively in many fields.[0006]Various manufacturing methods of such nanoparticles as descri...

AI Technical Summary

Benefits of technology

[0023]In conventional manufacturing methods, as described in the summary above, because of the occurrence of “re-reaggregation behavior”, the ratio in which coarse particles having particle diameters of not less than 20 nm are produced is very high, thereby posing a problem. According to the nanoparticle manufacturing device and nanoparticle manufacturing method of the present invention, because the heating space, the cooling space and the collection space form a continuous flow path without a back flow, and because the cross-sectional area of the collection space is set at a large value compared to the cross-sectional area of the heating space and the cooling space, it is possible to substantially reduce the possibility that the above-described “reaggregation behavior” occur and it becomes possible to perform the manufacture of nanoparticles composed of single metals having particle diameters of the order of 5 nm to 10 nm.(B) Nanoparticle-dispersed liquid alkali metal

[0027]According to the method of manufacturing a nanoparticle-dispersed liquid alkali metal of the present invention, even by using nanoparticles aggregating together and nanoparticles having necking, it is possible to manufacture a nanoparticle-dispersed liquid alkali metal which has good dispersibility of nanoparticles and can maintain the state of dispersion even after a lapse of time.

[0028]As a result of this, by uniformly dispersing nanoparticles in a liquid alkali metal, it is possible to improve the suppression of the thermal conductivity and chemical activity (reactions to water and the like) of the liquid alkali metal. Furthermore, it is possible to stably maintain the fluidity and the like which liquid alkali metals essentially have.

Problems solved by technology

Because of the occurrence of these behavior, the ratio in which coarse particles having particle diameters of not less than 20 nm are produced is very high, thereby posing a problem.

On the other hand, however, liquid alkali metals of sodium or the like have high chemical activity and provide such properties that they can cause severe chemical reactions leading to explosions when they come into contact with air and water.

However, this poses the problems that high-level technologies are required and that the construction cost is high.

That is, there are various kinds of nanoparticles to be input, and for example, in the case of a particle whose primary particle diameter is not more than several tens of nanometers, because of the small particle diameter, the proportion of the number of atoms on the surface to the number of atoms forming a nanoparticle increases and the surface energy increases, causing secondary aggregation, with the result that the dispersibility to liquid sodium worsens.

Also, in the case of nanoparticles whose primary particles are chained to generate the necking behavior, secondary aggregation occurs due to tangling and the like and the dispersibility to liquid sodium tends to worsen.

In handling such nanoparticles, simply putting nanoparticles into liquid sodium and stirring the nanoparticles posed the problem that many particles settle although part of the particles are dispersed, resulting in low dispersibility to liquid sodium.

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